|
|
Cisco's implementation of the Internet Protocol (IP) suite provides all major services contained in the TCP/IP specifications.
Use the commands in this chapter to configure and monitor the IP routing protocols. For IP routing protocol configuration information and examples, refer to the "Configuring IP Routing Protocols" chapter of the Access and Communication Servers Configuration Guide.
Use the aggregate-address router configuration command to create an aggregate entry in a BGP routing table. Use the no form of this command to disable this feature.
aggregate-address address mask [as-set] [summary-only] [suppress-map map-name]| address | Aggregate address. |
| mask | Aggregate mask. |
| as-set | (Optional) Generates autonomous system set path information. |
| summary-only | (Optional) Filters more specific routes from updates. |
| suppress-map map-name | (Optional) Name of route-map to suppress. |
Disabled
Router configuration
You can implement aggregate routing in BGP either by redistributing an aggregate route into BGP or by using this conditional aggregate routing feature.
Using the aggregate-address command with no arguments will create an aggregate entry in the BGP routing table if there are any more-specific routes available that fall in the specified range. The aggregate route will be advertised as coming from your autonomous system and has the atomic aggregate attribute set to show that information might be missing. (By default, the atomic aggregate attribute is set unless you specify the as-set keyword in the aggregate-address command.)
Using the as-set keyword creates an aggregate entry using the same rules that the command follows without this keyword, but the path advertised for this route will be an AS_SET consisting of all elements contained in all paths that are being summarized. Do not use this form of aggregate-address when aggregating many paths, because this route must be continually withdrawn and re-updated as autonomous system path reachability information for the summarized routes changes.
Using the summary-only keyword not only creates the aggregate route (for example, 193.*.*.*) but will also suppress advertisements of more specific routes to all neighbors. If you only want to suppress advertisements to certain neighbors, you may use the neighbor distribute-list command, with caution. If a more-specific route leaks out, all BGP speakers will prefer that route over the less- specific aggregate you are generating (using longest-match routing).
Using the suppress-map keyword creates the aggregate route but suppresses advertisement of specified route maps. You can use the match clauses of route maps to selectively suppress some more specific routes of the aggregate and leave others unsuppressed. IP access lists and autonomous system path access lists match clauses are supported.
In the following example, an aggregate address is created. The path advertised for this route will be an AS_SET consisting of all elements contained in all paths that are being summarized.
router bgp 5
aggregate-address 193.0.0.0 255.0.0.0 as-set
match as-path
match ip address
route-map
Use the area authentication router configuration command to enable authentication for an OSPF area. Use the no form of this command with the authentication keyword to remove the area's authentication specification. Use the command no area area-id (with no other keywords) to remove the specified area from the communication server's configuration.
area area-id authentication| area-id | Identifier of the area for which authentication is to be enabled. The identifier can be specified as either a decimal value or an IP address. |
Type 0 authentication (no authentication)
Router configuration
Specifying authentication for an area sets the authentication to Type 1 (simple password) as specified in RFC 1247. If this command is not included in the configuration file, authentication of Type 0 (no authentication) is assumed.
The authentication type must be the same for all communication servers in an area. The authentication password for all OSPF communication servers on a network must be the same if they are to communicate with each other via OSPF. Use the ip ospf authentication-key interface configuration command to specify this password.
The following example mandates authentication for areas 0 and 36.0.0.0 of OSPF routing process 201. Authentication keys are also provided.
interface ethernet 0
ip address 131.119.251.201 255.255.255.0
ip ospf authentication-key adcdefgh
!
interface ethernet 1
ip address 36.56.0.201 255.255.0.0
ip ospf authentication-key ijklmnop
!
router ospf 201
network 36.0.0.0 0.255.255.255 area 36.0.0.0
network 131.119.0.0 0.0.255.255 area 0
area 36.0.0.0 authentication
area 0 authentication
area default-cost
area stub
ip ospf authentication-key
Use the area default-cost router configuration command to specify a cost for the default summary route sent into a stub area. Use the no form of this command to remove the assigned default route cost.
area area-id default-cost cost| area-id | Identifier for the stub area. The identifier can be specified as either a decimal value or as an IP address. |
| cost | Cost for the default summary route used for a stub area. The acceptable value is a 24-bit number. |
Cost of 1
Router configuration
This command is used only on an Area Border Router (ABR) attached to a stub area.
There are two stub area router configuration commands: the stub and default-cost options of the area command. In all communication servers attached to the stub area, the area should be configured as a stub area using the stub option of the area command. Use the default-cost option only on an ABR attached to the stub area. The default-cost option provides the metric for the summary default route generated by the ABR into the stub area.
The following example assigns a default-cost of 20 to stub network 36.0.0.0:
interface ethernet 0
ip address 36.56.0.201 255.255.0.0
!
router ospf 201
network 36.0.0.0 0.255.255.255 area 36.0.0.0
area 36.0.0.0 stub
area 36.0.0.0 default-cost 20
area authentication
area stub
Use the area range router configuration command to consolidate and summarize routes at an area boundary. Use the no form of this command to disable this function for the specified area.
area area-id range address mask| area-id | Identifier of the area about which routes are to be summarized. It can be specified as either a decimal value or as an IP address. |
| address | IP address. |
| mask | IP mask. |
Disabled
Router configuration
This command is only used with communication servers acting as Area Border Routers (ABRs). It is used to consolidate or summarize routes for an area. The result is that a single summary route is advertised to other areas by the ABR. Routing information is condensed at area boundaries. External to the area, a single route is advertised for each address range. This is called route summarization.
Multiple area router configuration commands specifying the range option can be configured. Thus, OSPF can summarize addresses for many different sets of address ranges.
The following example specifies one summary route to be advertised by the communication server acting as an ABR to other areas for all subnets on network 36.0.0.0 and for all hosts on network 192.42.110.0:
interface ethernet 0
ip address 192.42.110.201 255.255.255.0
!
interface ethernet 1
ip address 36.56.0.201 255.255.0.0
!
router ospf 201
network 36.0.0.0 0.255.255.255 area 36.0.0.0
network 192.42.110.0 0.0.0.255 area 0
area 36.0.0.0 range 36.0.0.0 255.0.0.0
area 0 range 192.42.110.0 255.255.255.0
Use the area stub router configuration command to define an area as a stub area. Use the no form of this command to disable this function for the specified area.
area area-id stub| area-id | Identifier for the stub area. The identifier can be either a decimal value or an IP address. |
No stub area is defined.
Router configuration
This command must be configured on all communication servers in the stub area. Use the area router configuration command with the default-cost option to specify the cost of a default internal communication server sent into a stub area by a communication server acting as an Area Border Router (ABR).
There are two stub area router configuration commands: the stub and default-cost options of the area router configuration command. In all communication servers attached to the stub area, the area should be configured as a stub area using the stub option of the area command. Use the default-cost option only on an ABR attached to the stub area. The default-cost option provides the metric for the summary default route generated by the ABR into the stub area.
The following example assigns a default cost of 20 to stub network 36.0.0.0:
interface ethernet 0
ip address 36.56.0.201 255.255.0.0
!
router ospf 201
network 36.0.0.0 0.255.255.255 area 36.0.0.0
area 36.0.0.0 stub
area 36.0.0.0 default-cost 20
area authentication
area default-cost
To define an OSPF virtual link, use the area virtual-link router configuration command with the optional parameters. To remove a virtual link, use the no form of this command.
area area-id virtual-link router-id [hello-interval seconds] [retransmit-interval seconds]| area-id | Area ID assigned to the transit area for the virtual link. This can be either a decimal value or a valid IP address. There is no default. |
| router-id | Router ID associated with the virtual link neighbor. The router ID appears in the show ip ospf display. It is internally derived by each communication server from the communication server's interface IP addresses. This value must be entered in the format of an IP address. There is no default. |
| hello-interval | (Optional) Time in seconds between the Hello packets that the communication server sends on an interface. |
| seconds | (Optional) Unsigned integer value to be advertised in the communication server's Hello packets. The value must be the same for all communication servers attached to a common network. The default is 10 seconds. |
| retransmit-interval | (Optional) Time in seconds between link state advertisement retransmissions for adjacencies belonging to the interface. |
| seconds | (Optional) Expected round-trip delay between any two communication servers on the attached network. The value must be greater than the expected round-trip delay. The default is 5 seconds. |
| transmit-delay | (Optional) Estimated time in seconds it takes to transmit a link state update packet on the interface. |
| seconds | (Optional) Integer value that must be greater than zero. Link state advertisements in the update packet have their age incremented by this amount before transmission. The default value is 1 second. |
| dead-interval | (Optional) Time in seconds that a communication server's Hello packets are not seen before its neighbors declare the communication server down. |
| seconds | (Optional) Unsigned integer value. The default is four times the Hello interval, or 40 seconds. As with the Hello interval, this value must be the same for all communication servers attached to a common network. |
| authentication-key | (Optional) Password to be used by neighboring communication servers. |
| password | (Optional) Any continuous string of characters that you can enter from the keyboard up to 8 bytes in length. This string acts as a key that will allow the authentication procedure to generate or verify the authentication field in the OSPF header. This key is inserted directly into the OSPF header when originating routing protocol packets. A separate password can be assigned to each network on a per-interface basis. All neighboring communication servers on the same network must have the same password to be able to route OSPF traffic. The password is encrypted in the configuration file if the service password-encryption command is enabled. There is no default value. |
area-id: No area ID is predefined.
router-id: No router ID is predefined.
hello-interval seconds: 10 seconds
retransmit-interval seconds: 10 seconds
transmit-delay seconds: 1 second
dead-interval seconds: 40 seconds
authentication-key password: No password is predefined.
Router configuration
In OSPF, all areas must be connected to a backbone area. If the connection to the backbone is lost, it can be repaired by establishing a virtual link.
The smaller the Hello interval, the faster topological changes will be detected, but more routing traffic will ensue.
The setting of the retransmit interval should be conservative, or needless retransmissions will result. The value should be larger for serial lines and virtual links.
The transmit delay value should take into account the transmission and propagation delays for the interface.
A communication server will use the specified authentication key only when authentication is enabled for the backbone with the area area-id authentication router configuration command.
Any keywords and arguments you specify after the authentication-key password keyword-argument pair are ignored. Therefore, specify any optional arguments before this keyword-argument pair.
The following example establishes a virtual link with default values for all optional parameters:
router ospf 201
network 36.0.0.0 0.255.255.255 area 36.0.0.0
area 36.0.0.0 virtual-link 36.3.4.5
A dagger (+) indicates that the command is documented in another chapter.
area authentication
service password-encryption +
show ip ospf
Use the autonomous-system global configuration command to specify the local autonomous system that the communication server resides in for EGP. Use the no form of this command to remove the autonomous system number.
autonomous-system local-as| local-as | Local autonomous system number to which the communication server belongs |
No local autonomous system is specified.
Global configuration
Before you can set up EGP routing, you must specify an autonomous system number. The local autonomous system number will be included in EGP messages sent by the communication server.
The following sample configuration specifies an autonomous system number of 110:
autonomous-system 110
router egp
To restore the default behavior of automatic summarization of subnet routes into network-level routes, use the use the auto-summary router configuration command. To disable this feature, use the no form of this command.
auto-summaryThis command has no arguments or keywords.
Enabled
Router configuration
By default, BGP does not accept subnets redistributed from IGP. To advertise and carry subnet routes in BGP, use an explicit network command or the no auto-summary command. If you disable auto-summarization and have not entered a network command, you will not advertise network routes for networks with subnet routes unless they contain a summary route.
IP Enhanced IGRP summary routes are given an administrative distance value of 5. You cannot configure this value.
In the following example, network numbers are not summarized automatically:
router bgp 6
no auto-summary
The following example disables automatic summarization for router process eigrp 109:
router eigrp 109
no auto-summary
ip summary-address eigrp
Use the bgp default local-preference router configuration command to change the default local preference value of 100. Use the no form of this command to revert to the default setting.
bgp default local-preference value| value | Local preference value. Higher is more preferred. Integer from 0 through 4294967295. |
Local preference value of 100
Router configuration
Generally, the default value of 100 allows you to easily define a particular path as less preferable than paths with no local preference attribute. The preference is sent to all communication servers in the local autonomous system.
In the following example, the default local preference value is raised from the default of 100 to 200:
router bgp 200
bgp default local-preference 200
set local-preference
Use the bgp fast-external-fallover router configuration command to immediately reset the BGP sessions of any directly adjacent external peers if the link used to reach them goes down. Use the no form of this command to disable this feature.
bgp fast-external-falloverThis command has no arguments or keywords.
Enabled
Router configuration
In the following example, the automatic resetting of BGP sessions is disabled:
router bgp 109
no bgp fast-external-fallover
Use the clear arp-cache EXEC command to remove all dynamic entries from the ARP cache and to clear the fast-switching cache.
clear arp-cacheThis command has no arguments or keywords.
EXEC
The following example removes all dynamic entries from the ARP cache and clears the fast-switching cache:
clear arp-cache
To reset a BGP connection, use the clear ip bgp EXEC command at the system prompt.
clear ip bgp {* | address}| * | Resets all current BGP sessions. |
| address | Resets only the identified BGP neighbor. |
EXEC
Use this command whenever any of the following changes occur:
The following example resets all current BGP sessions:
clear ip bgp *
show ip bgp
timers bgp
To delete entries from the neighbor table, use the clear ip eigrp neighbors EXEC command.
clear ip eigrp neighbors [ip-address | type number]| ip-address | (Optional) Address of the neighbor. |
| type | (Optional) Interface type. |
| number | (Optional) Interface number. |
EXEC
The following example removes the neighbor whose address is 160.20.8.3:
clear ip eigrp neighbors 160.20.8.3
show ip eigrp neighbors
To delete entries from the IGMP cache, use the clear ip igmp group EXEC command.
clear ip igmp group [group-name | group-address | type number]| group-name | (Optional) Name of the multicast group, as defined in the DNS hosts table or with the ip host command. |
| group-address | (Optional) Address of the multicast group. This is a multicast IP address in four-part dotted notation. |
| type | (Optional) Interface type. |
| number | (Optional) Interface number. |
EXEC
The IGMP cache contains a list of the multicast groups of which hosts on the directly connected LAN are members. If the communication server has joined a group, it is also listed in the cache.
To delete all entries from the IGMP cache, specify the clear ip igmp group command with no arguments.
The following example clears entries for the multicast group 224.0.255.1 from the IGMP cache:
clear ip igmp group 224.0.255.1
A dagger (+) indicates that the command is documented in another chapter.
ip host +
show ip igmp groups
show ip igmp interface
To delete entries from the IP multicast routing table, use the clear ip mroute EXEC command.
clear ip mroute * | {group-name [source-address] | group-address [source-address]}| * | Deletes all entries from the IP multicast routing table. |
| group-name | Name of the multicast group, as defined in the DNS hosts table or with the ip host command. |
| group-address | Address of the multicast group. This is a multicast IP address in four-part dotted notation. |
| source-address | (Optional) Address of a multicast source that is transmitting to the group. A source does not need to be a member of the group. If you specify source-address, you must specify either group-name or group-address. |
EXEC
The following example deletes all entries from the IP multicast routing table:
clear ip mroute *
The following example deletes from the IP multicast routing table all sources on the 10.3.0.0 subnet that are transmitting to the multicast group 224.2.205.42. Note that this example deletes all sources on network 10.3, not individual sources.
clear ip mroute 224.2.205.42 10.3.0.0
A dagger (+) indicates that the command is documented in another chapter.
ip host +
show ip mroute
Use the clear ip route EXEC command to remove one or more routes from the IP routing table.
clear ip route {network [mask] | *}| network | Network or subnet address to remove. |
| mask | (Optional) Network mask associated with the IP address you wish to remove. |
| * | Removes all entries. |
EXEC
The following example removes a route to network 132.5.0.0 from the IP routing table:
clear ip route 132.5.0.0
show ip route
To control the redistribution of routing information between IGRP or Enhanced IGRP processes, use the default-information allowed router configuration command. To suppress IGRP or Enhanced IGRP exterior or default routes when they are received by an Enhanced IGRP process, use the no default-information allowed in command. To suppress IGRP or Enhanced IGRP exterior routes in updates, use the no default-information allowed out command.
default-information allowed {in | out} [route-map map-tag]| in | Allows IGRP or Enhanced IGRP exterior or default routes to be received by an IGRP process. |
| out | Allows IGRP or Enhanced IGRP exterior routes to be advertised in updates. |
| route-map map-tag | (Optional) Indicates that the route map should be interrogated to filter the importation of routes from this source routing protocol to the current routing protocol. The argument map-tag is the identifier of a configured route map. If you specify route-map without specifying map-tag, no routes are imported. If you omit route-map, all routes are redistributed. |
Normally, exterior routes are always accepted and default information is passed between IGRP or Enhanced IGRP processes when doing redistribution.
Router configuration
The default network of 0.0.0.0 used by RIP cannot be redistributed by IGRP or Enhanced IGRP.
The no default-information allowed command filters candidate default information out of routing updates. It has no effect on redistribution.
The following example allows IGRP exterior or default routes to be received by the IGRP process in autonomous system 23:
router igrp 23
default-information allowed in
The following example allows IP Enhanced IGRP exterior or default routes to be received by the IP Enhanced IGRP process in autonomous system 23:
router eigrp 23
default-information allowed in
Use the default-information originate router configuration command to allow the redistribution of network 0.0.0.0 into BGP. Use the no form of this command to prevent the redistribution of network 0.0.0.0 into BGP.
default-information originateThis command has no arguments or keywords.
Disabled
Router configuration
The same functionality will result from the network 0.0.0.0 command, using the network router configuration command.
The following example configures BGP to redistribute network 0.0.0.0 into BGP:
router bgp 164
default-information originate
Use the default-information originate router configuration command to explicitly configure EGP to generate a default route. Use the no form of this command to disable this function.
default-information originateThis command has no arguments or keywords.
Disabled
Router configuration
Because EGP can use network 0.0.0.0 as a default route, EGP must be explicitly configured to generate a default route. If the next hop for the default route can be advertised as a third party, it will be included as a third party.
The following example configures EGP to generate a default route:
autonomous system 109
router egp 164
network 131.108.0.0
network 192.31.7.0
neighbor 10.2.0.2
default-information originate
Use the default-information originate router configuration command to generate a default route into an OSPF routing domain. Use the no form of this command to disable generation of a default route into the specified OSPF routing domain.
default-information originate [always] [metric metric-value] [metric-type type-value]| originate | For OSPF, causes the communication server to generate a default external route into an OSPF domain if the communication server already has a default route and you want to propagate to other communication servers. |
| always | (Optional) For OSPF, the default route always will be advertised whether or not the communication server has a default route. |
| metric metric-value | (Optional) Metric used for generating the default route. If a value is not specified for this option, and no value is specified using the default-metric router configuration command, the default metric value is 10. The value used is specific to the protocol. |
| metric-type type-value | (Optional) For OSPF, the external link type associated with the default route advertised into the OSPF routing domain. It can be one of two values:
1--Type 1 external route 2--Type 2 external route If a metric-type is not specified, the communication server adopts a Type 2 external route. |
| route-map map-name | (Optional) Routing process will generate the default route if the route-map is satisfied. |
Disabled
Router configuration
Whenever you use the redistribute or the default-information router configuration commands to redistribute routes into an OSPF routing domain, the communication server automatically becomes an Autonomous System Boundary Router. However, an Autonomous System Boundary Router does not, by default, generate a default route into the OSPF routing domain. The communication server still needs to have a default route for itself before it generates one, except when you have specified the always keyword.
When you use this command for the OSPF process, the default network must reside in the routing table and you must satisfy the route-map map-name keyword. Use the default-information originate always route-map map-name form of the command when you do not want the dependency on the default network in the routing table.
The following example specifies a metric of 100 for the default route redistributed into the OSPF routing domain and an external metric type of Type 1:
router ospf 109
redistribute igrp 108 metric 100 subnets
default-information originate metric 100 metric-type 1
redistribute
Use the default-metric router configuration command to set default metric values for the RIP, EGP, IGRP, Enhanced IGRP, and BGP routing protocols. Use the no form of this command to remove the metric value and return to the default state.
default-metric number| number | Default metric value appropriate for the specified routing protocol |
Built-in, automatic metric translations, as appropriate for each routing protocol
Router configuration
This command is used in conjunction with the redistribute router configuration command to cause the current routing protocol to use the same metric value for all redistributed routes. A default metric helps solve the problem of redistributing routes with incompatible metrics. Whenever metrics do not convert, using a default metric provides a reasonable substitute and enables the redistribution to proceed.
In BGP, this sets the MULTI_EXIT_DISC metric. (The name of this metric for BGP Versions 2 and 3 is INTER_AS.)
The following example shows a communication server in autonomous system 109 using both the RIP and the IGRP routing protocols. The example advertises IGRP-derived routes using the RIP protocol and assigns the IGRP-derived routes a RIP metric of 10.
router rip
default-metric 10
redistribute igrp 109
redistribute
Use this form of the default-metric router configuration command to set metrics for IGRP. Use the no form of this command to remove the metric value and return to the default state.
default-metric bandwidth delay reliability loading mtu| bandwidth | Minimum bandwidth of the route in kilobits per second |
| delay | Route delay in tens of microseconds |
| reliability | Likelihood of successful packet transmission expressed as a number between 0 and 255 (255 is 100 percent reliability) |
| loading | Effective bandwidth of the route expressed as a number between 0 and 255 (255 is 100 percent loading) |
| mtu | Minimum Maximum Transmission Unit (MTU) size for the route |
Built-in, automatic metric translations
Router configuration
IGRP metric defaults have been carefully set to work for a wide variety of networks. Take great care in changing these values.
Automatic metric translations for IGRP are only supported when redistributing from IGRP or static.
The following example takes redistributed RIP metrics and translates them into IGRP metrics with values as follows: bandwidth = 1000, delay = 100, reliability = 250, loading = 100, and mtu =1500.
router igrp 109
network 131.108.0.0
redistribute rip
default-metric 1000 100 250 100 1500
redistribute
To define an administrative distance, use the distance router configuration command. To remove a distance definition, use the no form of this command.
distance weight [address mask [access-list-number]] [ip]| weight | Administrative distance. This can be an integer from 10 to 255. (The values 0 through 9 are reserved for internal use.) Used alone, the argument weight specifies a default administrative distance that the communication server uses when no other specification exists for a routing information source. Routes with a distance of 255 are not installed in the routing table. |
| address | (Optional) IP address in four-part dotted notation. |
| mask | (Optional) IP address mask in four-part dotted-decimal format. A bit set to 1 in the mask argument instructs the communication server to ignore the corresponding bit in the address value. |
| access-list-number | (Optional) Number of a standard IP access list to be applied to incoming routing updates. |
| ip | (Optional) IP-derived routes for IS-IS. Can be applied independently for IP routes and ISO CLNS routes. |
Default administrative distances are shown in Table 18-1.
| Route Source | Default Distance |
|---|---|
| Connected interface | 0 |
| Static route | 1 |
| External BGP | 20 |
| IGRP | 100 |
| OSPF | 110 |
| RIP | 120 |
| EGP | 140 |
| Internal BGP | 200 |
| Unknown | 255 |
Router configuration
Numerically, an administrative distance is an integer between 0 and 255. In general, the higher the value, the lower the trust rating. An administrative distance of 255 means the routing information source cannot be trusted at all and should be ignored.
When the optional access list number is used with this command, it is applied when a network is being inserted into the routing table. This behavior allows filtering of networks according to the IP address of the communication server supplying the routing information. This could be used, as an example, to filter out possibly incorrect routing information from communication servers not under your administrative control.
The order in which you enter distance commands can affect the assigned administrative distances in unexpected ways (see "Example" for further clarification).
Weight values are also subjective; there is no quantitative method for choosing weight values.
For BGP, the distance command sets the administrative distance of the External BGP route.
The show ip protocols EXEC command displays the default administrative distance for a specified routing process.
In the following example, the router igrp global configuration command sets up IGRP routing in autonomous system number 109. The network router configuration commands specify IGRP routing on networks 192.31.7.0 and 128.88.0.0. The first distance router configuration command sets the default administrative distance to 255, which instructs the communication server to ignore all routing updates from communication servers for which an explicit distance has not been set. The second distance command sets the administrative distance for all communication servers on the Class C network 192.31.7.0 to 90. The third distance command sets the administrative distance for the communication server with the address 128.88.1.3 to 120.
router igrp 109
network 192.31.7.0
network 128.88.0.0
distance 255
distance 90 192.31.7.0 0.0.0.255
distance 120 128.88.1.3 0.0.0.0
distance bgp
To allow the use of external, internal, and local administrative distances that could be a better route to a node, use the distance bgp router configuration command. To return to the default values, use the no form of this command.
distance bgp external-distance internal-distance local-distance| external-distance | Administrative distance for BGP external routes. External routes are routes for which the best path is learned from a neighbor external to the autonomous system. Acceptable values are from 1 to 255. The default is 20. Routes with a distance of 255 are not installed in the routing table. |
| internal-distance | Administrative distance for BGP internal routes. Internal routes are those routes that are learned from another BGP entity within the same autonomous system. Acceptable values are from 1 to 255. The default is 200. Routes with a distance of 255 are not installed in the routing table. |
| local-distance | Administrative distance for BGP local routes. Local routes are those networks listed with a network router configuration command, often as back doors, for that communication server or for networks that are being redistributed from another process. Acceptable values are from 1 to 255. The default is 200. Routes with a distance of 255 are not installed in the routing table. |
external-distance = 20
internal-distance = 200
local-distance = 200
Router configuration
An administrative distance is a rating of the trustworthiness of a routing information source, such as an individual communication server or a group of communication servers. Numerically, an administrative distance is an integer between 0 and 255. In general, the higher the value, the lower the trust rating. An administrative distance of 255 means the routing information source cannot be trusted at all and should be ignored.
Use this command if another protocol is known to be able to provide a better route to a node than was actually learned via external BGP, or if some internal routes should really be preferred by BGP.
In the following example, internal routes are known to be preferable to those learned through the IGP, so the administrative distance values are set accordingly:
router bgp 109
network 131.108.0.0
neighbor 129.140.6.6 remote-as 123
neighbor 128.125.1.1 remote-as 47
distance bgp 20 20 200
distance
To allow the use of internal and external administrative distances that could be a better route to a node, use the distance eigrp router configuration command. To reset these values to their defaults, use the no form of this command.
distance eigrp internal-distance external-distance| internal-distance | Administrative distance for IP Enhanced IGRP internal routes. Internal routes are those that are learned from another entity within the same autonomous system. It can be a value from 1 to 255. The default is 90. |
| external-distance | Administrative distance for IP Enhanced IGRP external routes. External routes are those for which the best path is learned from a neighbor external to the autonomous system. It can be a value from 1 to 255. The default is 170. |
internal-distance: 90
external-distance: 170
Router configuration
An administrative distance is a rating of the trustworthiness of a routing information source, such as an individual communication server or a group of communication servers. Numerically, an administrative distance is an integer between 0 and 255. In general, the higher the value, the lower the trust rating. An administrative distance of 255 means the routing information source cannot be trusted at all and should be ignored.
Use the distance eigrp command if another protocol is known to be able to provide a better route to a node than was actually learned via external IP Enhanced IGRP or if some internal routes should really be preferred by IP Enhanced IGRP.
Table 18-2 lists the default administrative distances.
| Route Source | Default Distance |
|---|---|
| Connected interface | 0 |
| Static route | 1 |
| Enhanced IGRP summary route | 5 |
| External BGP | 20 |
| Internal Enhanced IGRP | 90 |
| IGRP | 100 |
| OSPF | 110 |
| IS-IS | 115 |
| RIP | 120 |
| EGP | 140 |
| External Enhanced IGRP | 170 |
| Internal BGP | 200 |
| Unknown | 255 |
To display the default administrative distance for a specified routing process, use the show ip protocols EXEC command.
In the following example, the router eigrp global configuration command sets up IP Enhanced IGRP routing in autonomous system number 109. The network router configuration commands specify IP Enhanced IGRP routing on networks 192.31.7.0 and 128.88.0.0. The first distance router configuration command sets the default administrative distance to 255, which instructs the communication server to ignore all routing updates from communication servers for which an explicit distance has not been set. The second distance router configuration command sets the administrative distance for all communication servers on the Class C network 192.31.7.0 to 90. The third distance router configuration command sets the administrative distance for the communication server with the address 128.88.1.3 to 120.
router eigrp 109
network 192.31.7.0
network 128.88.0.0
distance 255
!
! use caution when executing the next two commands!
!
distance 90 192.31.7.0 0.0.0.255
distance 120 128.88.1.3 0.0.0.0
show ip protocols
To filter networks received in updates, use the distribute-list in router configuration command. To change or cancel the filter, use the no form of this command.
distribute-list access-list-number in [type number]| access-list-number | Standard IP access list number. The list defines which networks are to be received and which are to be suppressed in routing updates. |
| type | (Optional) Interface type. |
| number | (Optional) Interface number. |
Disabled
Router configuration
If no interface is specified, the access list will be applied to all incoming updates.
The following example causes only two networks to be accepted by a RIP routing process: network 0.0.0.0 (the RIP default) and network 131.108.0.0.
access-list 1 permit 0.0.0.0
access-list 1 permit 131.108.0.0
access-list 1 deny 0.0.0.0 255.255.255.255
router rip
network 131.108.0.0
distribute-list 1 in
A dagger (+) indicates that the command is documented in another chapter.
access-list +
distribute-list out
redistribute
To suppress networks from being advertised in updates, use the distribute-list out router configuration command. To cancel this function, use the no form of this command.
distribute-list access-list-number out [interface-name | routing-process || access-list-number | Standard IP access list number. The list defines which networks are to be sent and which are to be suppressed in routing updates. |
| interface-name | (Optional) Name of a particular interface. Does not apply to OSPF. |
| routing-process | (Optional) Name of a particular routing process, or the keyword static or connected. |
| autonomous-system-number | A decimal number between 1 and 65535. |
Disabled
Router configuration
When redistributing networks, a routing process name can be specified as an optional trailing argument to the distribute-list command. This causes the access list to be applied to only those routes derived from the specified routing process. After the process-specific access list is applied, any access list specified by a distribute-list command without a process name argument will be applied. Addresses not specified in the distribute-list command will not be advertised in outgoing routing updates.
The following example would cause only one network to be advertised by a RIP routing process: network 131.108.0.0.
access-list 1 permit 131.108.0.0
access-list 1 deny 0.0.0.0 255.255.255.255
router rip
network 131.108.0.0
distribute-list 1 out
A dagger (+) indicates that the command is documented in another chapter.
access-list +
distribute-list in
redistribute
Use the ip address interface configuration command to specify the IP address on an interface. Use the no form of this command to remove the specified secondary address.
ip address address mask [secondary]| address | IP address |
| mask | IP address mask |
| secondary | (Optional) Address to be added as a secondary address |
Disabled
Interface configuration
The optional keyword secondary allows an unlimited number of secondary addresses to be specified. Secondary addresses are treated like primary addresses, except that the system never generates datagrams other than routing updates with secondary source addresses. IP broadcasts and ARP requests are handled properly, as are interface routes in the IP routing table.
Secondary IP addresses can be used in a variety of situations. The following are the most common applications:
The following example specifies 131.108.1.27 as the primary address and 192.31.7.17 as a secondary address for Ethernet interface 0:
interface ethernet 0
ip address 131.108.1.27 255.255.255.0
ip address 192.31.7.17 255.255.255.0 secondary
Use the ip as-path access-list global configuration command to define a BGP-related access list. Use the no form of this command to disable use of the access list.
ip as-path access-list access-list-number {permit | deny} as-regular-expression| access-list-number | Integer from 1 to 199 that indicates the regular expression access list number. |
| permit | Permits access for matching conditions. |
| deny | Denies access to matching conditions. |
| as-regular-expression | Autonomous system in the access list using a regular expression. See the "Regular Expressions" appendix for information on forming regular expressions. |
No access lists are defined.
Global configuration
You can specify an access list filter on both inbound and outbound BGP routes. In addition, you can assign weights based on a set of filters. Each filter is an access list based on regular expressions. If the regular expression matches the representation of the autonomous system path of the route as an ASCII string, then the permit or deny condition applies. The autonomous system path does not contain the local autonomous system number. Use the ip as-path access-list global configuration command to define an BGP access list, and the neighbor router configuration command to apply a specific access list.
See the "Regular Expressions" appendix for information on forming regular expressions.
The following example specifies that the BGP neighbor with IP address 128.125.1.1 is not sent advertisements about any path through or from the adjacent autonomous system 123:
ip as-path access-list 1 deny _123_
ip as-path access-list 1 deny ^123 .*
! The space in the above expression (^123.*) is required.
router bgp 109
network 131.108.0.0
neighbor 129.140.6.6 remote-as 123
neighbor 128.125.1.1 remote-as 47
neighbor 128.125.1.1 filter-list 1 out
neighbor distribute-list
neighbor filter-list
Use the ip default-network global configuration command to select a network as a candidate route for computing the gateway of last resort. Use the no form of this command to remove the route.
ip default-network network-number| network-number | Number of the network |
If the communication server has a directly connected interface onto the specified network, the dynamic routing protocols running on that communication server will generate (or source) a default route. For RIP, this is flagged as the pseudonetwork 0.0.0.0; for IGRP, it is the network itself, flagged as an exterior route.
Global configuration
The communication server uses both administrative distance and metric information to determine the default route. Multiple ip default-network commands can be given. All candidate default routes, both static (that is, flagged by ip default-network) and dynamic, appear in the routing table preceded by an asterisk.
If the IP routing table indicates that the specified network number is subnetted and a non-zero subnet number is specified, then the system will automatically configure a static summary route. This static summary route is configured instead of a default network. The effect of the static summary route is to cause traffic destined for subnets that are not explicitly listed in the IP routing table to be routed using the specified subnet.
The following example defines a static route to network 10.0.0.0 as the static default route:
ip route 10.0.0.0 255.0.0.0 131.108.3.4
ip default-network 10.0.0.0
If the following command was issued on a communication server not connected to network 129.140.0.0, the communication server might choose the path to that network as a default route when the network appeared in the routing table:
ip default-network 129.140.0.0
show ip route
To configure an acceptance filter for incoming DVMRP reports, use the ip dvmrp accept-filter interface configuration command. To disable this feature, use the no form of this command.
ip dvmrp accept-filter access-list-number [distance]| access-list-number | Number of a standard IP access list. This can be a number from 1 to 99. A value of 0 means that all sources are accepted with the configured distance. |
| distance | (Optional) Administrative distance to the destination. |
All destinations are accepted with a distance of 0.
Interface configuration
Any sources that match the access list are stored in the DVMRP routing table.
The route with the lower distance (either the route in the unicast routing table or that in the DVMRP routing table) takes precedence when computing the Reverse Path Forwarding (RPF) interface for a source of a multicast packet.
By default, the administrative distance for DVMRP routes is 0. This means that they always take precedence over unicast routing table routes. If you have two paths to a source, one through unicast routing (using PIM as the multicast routing protocol) and another path using DVMRP (unicast and multicast routing), and if you want to use the PIM path, use the ip dvmrp accept-filter command to increase the administrative distance for DVMRP routes. For example, if the unicast routing protocol is Enhanced IGRP, which has a default administrative distance of 90, you could define and apply the following access list so the RPF interface used to accept multicast packets will be through the Enhanced IGRP/PIM path:
ip dvmrp accept-filter 1 100
access-list 1 permit 0.0.0.0 255.255.255.255
The following example applies access list 57 to the interface and sets a distance of 4:
access-list 57 permit 131.108.0.0 0.0.255.255
access-list 57 permit 198.92.37.0 0.0.0.255
access-list 57 deny 0.0.0.0 255.255.255.255
ip dvmrp accept-filter 57 4
distance
ip dvmrp metric
show ip dvmrp route
tunnel mode
To configure the metric associated with a set of destinations for DVMRP reports, use the ip dvmrp metric interface configuration command. To disable this function, use the no form of this command.
ip dvmrp metric metric [access-list-number] [protocol process-id]| metric | Metric associated with a set of destinations for DVMRP reports. It can be a value from 0 to 32. A value of 0 means that the route is not advertised. A value of 32 is equivalent to infinity (unreachable). |
| access-list-number | (Optional) Number of an access list. If you specify this argument, only the multicast destinations that match the access list are reported with the configured metric. Any destinations not advertised because of split horizon do not use the configured metric. |
| protocol | (Optional) Name of unicast routing protocol. It can be bgp, egp, eigrp, igrp, isis, ospf, rip, or static. (Note that these are the protocol names you can specify with a router protocol command.)
If you specify these arguments, only routes learned by the specified routing protocol are advertised in DVMRP report messages. |
| process-id | (Optional) Process ID number of the unicast routing protocol. |
No metric is preconfigured. Only directly connected subnets and networks are advertised to neighboring DVMRP communication servers.
Interface configuration
When PIM is configured on an interface and DVMRP neighbors are discovered, the communication server sends DVMRP report messages for directly connected networks. The ip dvmrp metric command enables DVMRP report messages for multicast destinations that match the access list. Usually, the metric for these routes is 1. Under certain circumstances, it may be desirable to tailor the metric used for various unicast routes.
Use the access-list-number argument in conjunction with the protocol process-id arguments to selectively list the destinations learned from a given routing protocol.
If you do not specify this command, only directly connected subnets are advertised via DVMRP.
To display DVMRP activity, use the debug ip dvmrp command.
The following example connects a PIM cloud to a DVMRP cloud. Access list 1 permits the sending of DVMRP reports to the DVMRP communication servers advertising all sources in the 198.92.35.0 network with a metric of 1. Access list 2 permits all other destinations, but the metric of 0 means that no DVMRP reports are sent for these destinations.
access-list 1 permit 198.92.35.0 0.0.0.255
access-list 1 deny 0.0.0.0 255.255.255.255
access-list 2 permit 0.0.0.0 255.255.255.255
interface tunnel 0
ip dvmrp metric 1 1
ip dvmrp metric 0 2
A dagger (+) indicates that the command is documented in the Debug Command Reference publication.
debug ip dvmrp +
ip dvmrp accept-filter
Use the ip gdp interface configuration command to enable GDP routing on an interface. Use the no form of this command to disable GDP routing, with all default parameters.
ip gdp [priority number | reporttime seconds | holdtime seconds]| priority number | (Optional) Alters the GDP priority; default is a priority of 100. A larger number indicates a higher priority. |
| reporttime seconds | (Optional) Alters the GDP reporting interval; the default is 5 seconds for broadcast media such as Ethernets, and never for nonbroadcast media such as X.25. |
| holdtime seconds | (Optional) Alters the GDP default hold time of 15 seconds. |
priority = 100
reporttime = 5 seconds for broadcast media; 0 for nonbroadcast media
holdtime = 15 seconds
Interface configuration
When enabled on an interface, GDP updates report the primary and secondary IP addresses of that interface.
In the following example, GDP is enabled on Ethernet interface 1 with a report time of 10 seconds, and priority and hold time set to their defaults (because none are specified):
interface ethernet 1
ip gdp reporttime 10
To configure the hello interval for the IP Enhanced IGRP routing process designated by an autonomous system number, use the ip hello-interval eigrp interface configuration command. To restore the default value, use the no form of this command.
ip hello-interval eigrp autonomous-system-number seconds| autonomous-system-number | A decimal number between 1 and 65535. |
| seconds | Hello interval, in seconds |
5 seconds
Interface configuration
The following example sets the hello interval for Ethernet interface 0 to 10 seconds:
interface ethernet 0
ip hello-interval eigrp 109 10
ip hold-time eigrp
To configure the hold time for the IP Enhanced IGRP routing process designated by the autonomous system number, use the ip hold-time eigrp interface configuration command. To restore the default value, use the no form of this command.
ip hold-time eigrp autonomous-system-number seconds| autonomous-system-number | A decimal number between 1 and 65535. |
| seconds | Hold time, in seconds |
15 seconds
Interface configuration
The hold time is three times the hello interval. If the current value for the hold time is less than two times the hello interval, the hold time is reset.
If a communication server does not receive a hello packet within the specified hold time, routes through the communication server are considered available.
Increasing the hold time delays route convergence across the network.
The following example sets the hold time for Ethernet interface 0 to 40 seconds:
interface ethernet 0
ip hold-time eigrp 109 40
ip hello-interval eigrp
To control the multicast groups that hosts on the subnet serviced on an interface can join, use the ip igmp access-group interface configuration command. To disable groups on an interface, use the no form of this command.
ip igmp access-group access-list-number| access-list-number | Number of a standard IP access list. This can be a number from 1 to 99. |
All groups are allowed on an interface.
Interface configuration
In the following example, host services by Ethernet interface 0 can join the group 225.2.2.2 only:
access-list 1 225.2.2.2 0.0.0.0
interface ethernet 0
ip igmp access-group 1
ip igmp join-group
To have the communication server join a multicast group, use the ip igmp join-group interface configuration command. To cancel membership in a multicast group, use the no form of this command.
ip igmp join-group group-address| group-address | Address of the multicast group. This is a multicast IP address in four-part dotted notation. |
No multicast group memberships are predefined.
Interface configuration
IP packets that are addressed to the group address are passed to the IP client process in the communication server.
If all the multicast-capable communication servers that you administer are members of a multicast group, pinging that group causes all communication servers to respond. This can be a useful administrative and debugging tool.
Another reason to have a communication server join a multicast group is when other hosts on the network have a bug in IGRP that prevents them from correctly answering IGMP queries. Having the communication server join the multicast group causes upstream communication servers to maintain multicast routing table information for that group and keeps the paths for that group active.
In the following example, the communication server joins multicast group 225.2.2.2:
ip igmp join-group 225.2.2.2
ip igmp access-group
ping
To configure the frequency at which the communication server sends IGMP host-query messages, use the ip igmp query-interval interface configuration command. To return to the default frequency, use the no form of this command.
ip igmp query-interval seconds| seconds | Frequency, in seconds, at which to transmit IGMP host-query messages. The can be a value from 0 to 65535. The default is 60 seconds. |
60 seconds
Interface configuration
Multicast communication servers send host membership query messages (referred to as host-query messages) to discover which multicast groups have members on the communication server's attached networks. Hosts respond with IGMP report messages indicating that they wish to receive multicast packets for specific groups (that is, indicating that the host wants to become a member of the group). Host-query messages are addresses to the all-hosts multicast group, which has the address 224.0.0.1, and have an IP TTL value of 1.
The designated router for a LAN is the only communication server that sends IGMP host-query messages. The designated router is elected according to the multicast routing protocol that runs on the LAN.
The following example changes the frequency at which the designated router sends IGMP host-query messages to 2 minutes:
interface tunnel 0
ip igmp query-interval 120
ip pim query-interval
show ip igmp groups
Use the ip irdp interface configuration command to enable ICMP Router Discovery Protocol (IRDP) processing on an interface. Use the no form of this command to disable IRDP routing on the specified interface.
ip irdp [multicast | holdtime seconds | maxadvertinterval seconds | minadvertinterval| multicast | (Optional) Use the multicast address (224.0.0.1) instead of IP broadcasts. |
| holdtime seconds | (Optional) Length of time in seconds advertisements are held valid. Default is three times the maxadvertinterval value. Must be greater than maxadvertinterval and cannot be greater than 9000 seconds. |
| maxadvertinterval seconds | (Optional) Maximum interval in seconds between advertisements. The default is 600 seconds. |
| minadvertinterval seconds | (Optional) Minimum interval in seconds between advertisements. The default is 0.75 times the maxadvertinterval. If you change the maxadvertinterval value, this value defaults to three-quarters of the new value. |
| preference number | (Optional) Communication server's preference value. The allowed range is -231 to 231. The default is 0. A higher value increases the communication server's preference level. You can modify a particular communication server so that it will be the preferred communication server to which others home. |
| address address [number] | (Optional) IP address (address) to proxy advertise, and optionally, its preference value (number). |
Disabled.
When enabled, IRDP uses these defaults:
Interface configuration
If you change maxadvertinterval, the other two values also change, so it is important to change maxadvertinterval first before changing either holdtime or minadvertinterval.
The ip irdp multicast command allows for compatibility with Sun Microsystems Solaris, which requires IRDP packets to be sent out as multicasts. Many implementations cannot receive these multicasts; ensure end host ability before using this command.
The following example illustrates how to set the various IRDP processes:
! enable irdp on interface Ethernet 0
interface ethernet 0
ip irdp
! send IRDP advertisements to the multicast address
ip irdp multicast
! increase communication server preference from 100 to 50
ip irdp preference 50
! set maximum time between advertisements to 400 secs
ip irdp maxadvertinterval 400
! set minimum time between advertisements to 100 secs
ip irdp minadvertinterval 100
! advertisements are good for 6000 seconds
ip irdp holdtime 6000
! proxy-advertise 131.108.14.5 with default communication server preference
ip irdp address 131.108.14.5
! proxy-advertise 131.108.14.6 with preference of 50
ip irdp address 131.108.14.6 50
To enable IP multicast routing on the communication server, use the ip multicast-routing global configuration command. To disable IP multicast routing, use the no form of this command.
ip multicast-routingThis command has no keywords or arguments.
IP multicast routing is disabled.
Global configuration
When IP multicast routing is disabled, the communication server does not forward any multicast packets.
The following example enables IP multicast routing on the communication server:
ip multicast-routing
ip pim
To configure the time-to-live (TTL) threshold of packets being forwarded out an interface, use the ip multicast-threshold interface configuration command. To return to the default TTL threshold, use the no form of this command.
ip multicast-threshold ttl| ttl | Time-to-live value, in hops. It can be a value from 0 to 255. The default value is 0, which means that all multicast packets are forwarded out the interface. |
0, which means that all multicast packets are forwarded on the interface.
Interface configuration
Any multicast packets with a TTL value less than the threshold are not forwarded out the interface.
You should configure the TTL threshold only on border routers. Conversely, communication servers on which you configure a TTL threshold value automatically become border routers.
In the following example, you set the TTL threshold on a border router to 200, which is a very high value. This means that multicast packets must have a TTL greater than 200 in order to be forwarded out this interface. Multicast applications generally set this value well below 200. Therefore, setting a value of 200 means that no packets will be forwarded out the interface.
interface tunnel 0
ip multicast-threshold 200
Use the ip ospf authentication-key interface configuration command to assign a password to be used by neighboring communication servers that are using OSPF's simple password authentication. Use the no form of this command to remove any previously assigned OSPF password.
ip ospf authentication-key password| password | Any continuous string of characters that can be entered from the keyboard up to 8 bytes in length. |
No password is specified.
Interface configuration
The password created by this command is used as a "key" that is inserted directly into the OSPF header when the communication server originates routing protocol packets. A separate password can be assigned to each network on a per-interface basis. All neighboring communication servers on the same network must have the same password to be able to exchange OSPF information.
In the following example, the authentication key is enabled with the string yourpass:
ip ospf authentication-key yourpass
area authentication
To explicitly specify the cost of sending a packet on an interface, use the ip ospf cost interface configuration command. To reset the path cost to the default value, use the no form of this command.
ip ospf cost cost| cost | Unsigned integer value expressed as the link state metric. It can be a value in the range 1 to 65535. |
No default cost is predefined.
Interface configuration
Unlike IGRP, you must set this metric manually using this command, if you need to change the default. Changing the bandwidth does not change the link cost.
The link state metric is advertised as the link cost in the communication server's router link advertisement. We do not support Type of Service (TOS), so you can assign only one cost per interface.
In general, the path cost is calculated as follows:
108 ÷ Bandwidth
Using the above formula, the default path costs were calculated as noted in the following list. If these values do not suit your network, you can use your own method of calculating path costs.
The following example sets the interface cost value to 65:
ip ospf cost 65
Use the ip ospf dead-interval interface configuration command to set the number of seconds that a communication server's Hello packets must not have been seen before its neighbors declare the communication server down. Use the no form of this command to reset the length of time to the default value.
ip ospf dead-interval seconds| seconds | Unsigned integer that specifies the interval in seconds; the value must be the same for all nodes on the network. |
Four times the interval set for the ip ospf hello-interval command
Interface configuration
The interval is advertised in the communication server's Hello packets. This value must be the same for all communication servers on a specific network.
The following example sets the OSPF dead interval to 60 seconds:
interface ethernet 1
ip ospf dead-interval 60
ip ospf hello-interval
Use the ip ospf hello-interval interface configuration command to specify the interval between Hello packets that the communication server sends on the interface. Use the no form of this command to reset the interval to the default value.
ip ospf hello-interval seconds| seconds | Unsigned integer that specifies the interval in seconds. The value must be the same for all nodes on a specific network. |
10 seconds
Interface configuration
This value is advertised in the communication server's Hello packets. The smaller the Hello interval, the faster topological changes will be detected, but more routing traffic will ensue. This value must be the same for all communication servers on a specific network.
The following example sets the interval between Hello packets to 15 seconds:
interface ethernet 1
ip ospf hello-interval 15
ip ospf dead-interval
Use the ip ospf network interface configuration command to configure the OSPF network type to a type other than the default for a given media. Use the no form of this command to restore the default.
ip ospf network {broadcast | non-broadcast}| broadcast | Sets the network type to broadcast. |
| non-broadcast | Sets the network type to nonbroadcast. |
Depends on the network type
Interface configuration
Using this feature, you can configure broadcast networks as nonbroadcast multiaccess networks when, for example, you have communication servers in your network that do not support multicast addressing. You can also configure nonbroadcast multiaccess networks, such as X.25, Frame Relay, and SMDS, as broadcast networks. This feature saves you from having to configure neighbors.
If this command is issued on an interface that does not allow it, it will be ignored.
The following example sets your OSPF network as a broadcast network:
interface serial 0
ip address 160.89.77.17 255.255.255.0
ip ospf network broadcast
encapsulation frame-relay
frame-relay map
neighbor (OSPF)
x25-map
Use the ip ospf priority interface configuration command to set the communication server's priority, which helps determine the designated communication server for this network. Use the no form of this command to reset the communication server priority to the default value.
ip ospf priority number| number | 8-bit unsigned integer that specifies the priority. The range is from 0 to 255. |
Priority of 1
Interface configuration
When two communication servers attached to a network both attempt to become the designated communication server; the one with the higher priority takes precedence. If there is a tie, the communication server with the higher ID takes precedence. A communication server with a priority set to zero is ineligible to become the designated communication server or backup designated communication server. Communication server priority is only configured for interfaces to multiaccess networks (in other words, not point-to-point networks).
This priority value is used when you configure OSPF for nonbroadcast networks using the neighbor router configuration command for OSPF.
The following example sets the communication server priority value to 4:
interface ethernet 0
ip ospf priority 4
ip ospf network
neighbor (OSPF)
To specify the number of seconds between link state advertisement retransmissions for adjacencies belonging to the interface, use the ip ospf retransmit-interval interface configuration command. Use the no form of this command to reset the link state advertisement retransmission interval to the default value.
ip ospf retransmit-interval seconds| seconds | Number of seconds between retransmissions; it must be greater than the expected round-trip delay between any two communication servers on the attached network. The range is 1 to 65535 seconds. The default is 5 seconds. |
5 seconds
Interface configuration
When a communication server sends a link state advertisement (LSA) to its neighbor, it keeps the LSA until it receives back the acknowledgment. If it receives no acknowledgment in seconds, it will retransmit the LSA.
The setting of this parameter should be conservative, or needless retransmission will result. The value should be larger for serial lines and virtual links.
The following example sets the retransmit-interval value to 8 seconds:
interface ethernet 2
ip ospf retransmit-interval 8
Use the ip ospf transmit-delay interface configuration command to set the estimated number of seconds it takes to transmit a link state update packet on the interface. Use the no form of this command to reset the estimated transmission time to the default value.
ip ospf transmit-delay seconds| seconds | Integer that specifies the number of seconds it takes to transmit a link state update. The range is 1 to 65535 seconds. |
1 second
Interface configuration
Link state advertisements in the update packet must have their age incremented by the amount specified in the seconds argument before transmission. The value assigned should take into account the transmission and propagation delays for the interface.
If the delay is not added before transmission over a link, the time in which the LSA propagates over the link is not considered. This setting has more significance on very low speed links.
The following example sets the retransmit-delay value to 3 seconds:
interface ethernet 0
ip ospf transmit-delay 3
Use the ip ospf-name-lookup global configuration command to configure OSPF to look up Domain Name System (DNS) names for use in all OSPF show EXEC command displays. Use the no form of this command to disable the feature.
ip ospf-name-lookupThis command has no arguments or keywords.
Disabled
Global configuration
This feature makes it easier to identify a communication server because it is displayed by name rather than by its communication server ID or neighbor ID.
The following example configures OSPF to look up DNS names for use in all OSPF show EXEC command displays:
ip ospf-name-lookup
The following is sample output of the show ip ospf database EXEC command, for example, once you have enabled the DNS name lookup feature.
cs# show ip ospf database
OSPF Router with id (160.89.41.1) (Autonomous system 109)
Router Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum Link count
160.89.41.1 cs 381 0x80000003 0x93BB 4
160.89.34.2 neon 380 0x80000003 0xD5C8 2
Net Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
160.89.32.1 cs 381 0x80000001 0xC117
To enable PIM on an interface, use the ip pim interface configuration command. To disable PIM on the interface, use the no form of this command.
ip pim [dense-mode | sparse-mode]| dense-mode | (Optional) Enables dense mode of operation. |
| sparse-mode | (Optional) Enables sparse mode of operation. |
IP multicast routing is disabled on all interfaces.
There is no default mode setting.
Interface configuration
Enabling PIM on an interface also enables IGMP operation on that interface. An interface can be configured to be in dense mode or sparse mode. The mode describes how the communication server populates its multicast routing table and how the communication server forwards multicast packets it receives from its directly connected LANs. In populating the multicast routing table, dense-mode interfaces are always added to the table. Sparse-mode interfaces are added to the table only when periodic join messages are received from downstream communication servers or there is a directly connected member on the interface.
Initially, a dense-mode interface forwards multicast packets until the communication server determines that there are group members or downstream communication servers, or until a prune message is received from a downstream communication server. Then, the dense-mode interface will periodically forward multicast packets out the interface until the same conditions occur. Dense mode assumes that there are multicast group members present. Dense-mode communication servers never send a join message. They do send prune messages as soon as they determine they have no members or downstream PIM communication servers.
A sparse-mode interface is used only for multicast forwarding if a join message is received from a downstream communication server or if there are group members directly connected to the interface. Sparse mode assumes that there are no other multicast group members present. When sparse-mode communication servers want to join the shared path, they periodically send join messages toward the RP. When sparse-mode communication servers want to join the source path, they periodically send join messages toward the source; they also send periodic prune messages toward to RP to prune the shared path.
The following command enables sparse-mode PIM on tunnel interface 0 and sets the address of the RP communication server to 226.0.0.8:
interface tunnel 0
ip pim sparse-mode
ip pim rp-address 226.0.0.8
The following commands enable dense-mode PIM multicast routing on Ethernet interface 1:
interface ethernet 1
ip pim dense-mode
ip multicast-routing
ip pim rp-address
show ip igmp interface
To configure the frequency at which a sparse-mode PIM communication server sends periodic sparse-mode
join/prune PIM messages, use the ip pim message-interval global configuration command. To return to the default interval, use the no form of this command.
| seconds | Interval, in seconds, at which periodic sparse-mode join and prune PIM messages are sent. It can be a number from 1 to 65535. The default is 60 seconds. |
60 seconds
Global configuration
The join-and-prune message interval should be the same for all communication servers in the internetwork.
A communication server is pruned from a group if a join message is not heard from it in three times the message interval specified by the seconds argument. By default, this is 3 minutes.
The following example changes the PIM message interval to 90 seconds:
ip pim message-interval 90
ip igmp query-interval
ip pim query-interval
To configure the frequency of PIM router-query messages, use the ip pim query-interval interface configuration command. To return to the default interval, use the no form of this command.
ip pim query-interval seconds| seconds | Interval, in seconds, at which periodic PIM router-query messages are sent. It can be a number from 1 to 65535. The default is 30 seconds. |
30 seconds
Interface configuration
Routers that are configured for IP multicast send PIM router-query messages to determine which communication server will be the designated router for each LAN segment (subnet). The designated router is responsible for sending IGMP host-query messages to all hosts on the directly connected LAN. When operating in sparse mode, the designated router is responsible for sending source registration messages to the RP. The designated router is the communication server with the largest IP address.
The following example changes the PIM router-query message interval to 45 seconds:
interface tunnel 0
ip pim query-interval 45
ip igmp query-interval
ip pim message-interval
To configure the address of a PIM rendezvous point (RP), use the ip pim rp-address global configuration command. To remove an RP address, use the no form of this command.
ip pim rp-address ip-address [access-list-number]| ip-address | IP address of a communication server to be a PIM RP. This is a unicast IP address in four-part dotted notation. |
| access-list-number | (Optional) Number of an access list that defines which multicast groups the RP should be used for. This is a standard IP access list. The number can be in the range 1 to 100. |
No PIM RPs are preconfigured.
Global configuration
You must configure the IP address of RPs in leaf routers only. Leaf routers are those communication servers that are directly connected either to a multicast group member or to a sender of multicast messages.
The RP address is used by first-hop communication servers to send register packets on behalf of source multicast hosts to the RP. This address is also used by communication servers on behalf of multicast hosts that want to become members of a group to send join messages towards the RP. The RP must be a PIM communication server; however, it does not require any special configuration to recognize that it is the RP. Also, RPs are not members of the multicast group; rather, they serve as a "meeting place" for multicast sources and group members.
Choosing the communication server that will be an RP requires prior coordination between the people who want to be members of the multicast group. You should examine the length of the paths between members and sources. Remember that most multicast members will eventually want to join to the source tree that is the shortest route between the source and the group member.
You can configure a communication server to use a single RP for more than one group. The conditions specified by the access list determine which groups the RP can be used for. If no access list is configured, the RP is used for all groups.
A PIM communication server can use multiple RPs.
First-hop communication servers for multicast sources send register packets to all configured RPs. First-hop communication servers for multicast group members send join packets to one RP at a time. Once this communication server begins receiving multicast packets for the group, it will have joined one RP tree. Because the communication server does not want to receive multiple copies of the same packet, it joins only one RP tree.
The following example sets the PIM RP address to 198.92.37.33 for all multicast groups:
ip pim rp-address 198.92.37.33
The following example sets the PIM RP address to 147.106.6.22 for the multicast group 225.2.2.2 only:
access list 1 225.2.2.2 0.0.0.0
pi pim rp-address 147.106.6.22 1
access-list
Use the ip route global configuration command to establish static routes. Use the no form of this command to remove the static routes.
ip route network [mask] {address | interface} [distance]| network | Internet address of the target network or subnet |
| mask | (Optional) Network mask that lets you mask network and subnetwork bits |
| address | Internet address of the next hop that can be used to reach that network |
| interface | Network interface to use |
| distance | (Optional) An administrative distance |
No static routes are established.
Global configuration
A static route is appropriate when the communication server cannot dynamically build a route to the destination.
If you specify an administrative distance, you are flagging a static route that can be overridden by dynamic information. For example, IGRP-derived routes have a default administrative distance of 100. To have a static route that would be overridden by an IGRP dynamic route, specify an administrative distance greater than 100. Static routes have a default administrative distance of 1.
Static routes that point to an interface will be advertised via RIP, IGRP, and other dynamic routing protocols, regardless of whether redistribute static commands were specified for those routing protocols. This is because static routes that point to an interface are considered in the routing table to be connected and hence lose their static nature. However, if you define a static route to an interface that is not one of the networks defined in a network command, no dynamic routing protocols will advertise the route unless a redistribute static command is specified for these protocols.
In the following example, an administrative distance of 110 was chosen. In this case, packets for network 10.0.0.0 will be routed through to the communication server at 131.108.3.4 if dynamic information with administrative distance less than 110 is not available.
ip route 10.0.0.0 255.0.0.0 131.108.3.4 110
In the following example, packets for network 131.108.0.0 will be routed to the communication server at 131.108.6.6:
ip route 131.108.0.0 255.255.0.0 131.108.6.6
Use the ip split-horizon interface configuration command to enable the split-horizon mechanism. Use the no form of this command to turn off the split-horizon mechanism.
ip split-horizonThis command has no arguments or keywords.
Varies with media
Interface configuration
For all interfaces except those for which either Frame Relay or SMDS encapsulation is enabled, the default condition for this command is ip split-horizon; in other words, the split horizon feature is active. If the interface configuration includes either the encapsulation frame-relay or encapsulation smds interface configuration commands, then the default is for split horizon to be disabled. Split horizon is not disabled by default for interfaces using any of the X.25 encapsulations.
If split horizon has been disabled on an interface and you wish to enable it, use the ip split-horizon command to restore the split horizon mechanism.
The following example illustrates a simple example of disabling split horizon on a serial link. In this example, the serial link is connected to an X.25 network:
interface serial 0
encapsulation x25
no ip split-horizon
To enable IP Enhanced IGRP split horizon, use the ip split-horizon eigrp interface configuration command. To disable split horizon, use the no form of this command.
ip split-horizon eigrp autonomous-system-number| autonomous-system-number | A decimal number between 1 and 65535. |
Enabled
Interface configuration
For networks that include links over X.25 PSNs, you can use the neighbor router configuration command to defeat the split horizon feature. As an alternative, you can explicitly specify the no ip split-horizon eigrp command in your configuration. However, if you do so, you must similarly disable split horizon for all communication servers in any relevant multicast groups on that network.
In general, it is recommended that you not change the default state of split horizon unless you are certain that your application requires the change in order to properly advertise routes. Remember that if split horizon is disabled on a serial interface and that interface is attached to a packet-switched network, you must disable split horizon for all communication servers in any relevant multicast groups on that network.
The following example disables split horizon on a serial link connected to an X.25 network:
interface serial 0
encapsulation x25
no ip split-horizon eigrp
ip split-horizon
neighbor
To configure a summary aggregate address for a specified interface, use the ip summary-address eigrp interface configuration command. To disable a configuration, use the no form of this command.
ip summary-address eigrp autonomous-system-number address mask| autonomous-system-number | A decimal number between 1 and 65535. |
| address | IP summary aggregate address to apply to an interface |
| mask | Subnet mask |
No summary aggregate addresses are predefined.
Interface configuration
IP Enhanced IGRP summary routes are given an administrative distance value of 5. You cannot configure this value.
The following example sets the IP summary aggregate address for Ethernet interface 0:
interface ethernet 0
ip summary-address eigrp 109 192.1.0.0 255.255.0.0
auto-summary
Use the match as-path route-map configuration command to match a BGP autonomous system path access list. Use the no form of this command to remove the path list entry.
match as-path path-list-number| path-list-number | Autonomous system path access list. An integer from 1 through 199. |
No path lists are defined.
Route-map configuration
The values set by the match and set commands override global values. For example, the weights assigned with the match as-path and set weight route-map commands override the weights assigned using the neighbor weight and neighbor filter-list commands.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want o modify only some data, you must configure second route-map section with an explicit match specified.
The implemented weight is based on the first matched autonomous system path.
In the following example, the autonomous system path is set to match BGP autonomous system path access list 20:
route-map igp2bgp
match as-path 20
route-map
set
To distribute any routes that have their next hop out one of the interfaces specified, use the match interface route-map configuration command. To remove the match interface entry, use the no form of this command.
match interface type number...type number| type | Interface type |
| number | Interface number |
No match interfaces are defined.
Route-map configuration
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands may be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want o modify only some data, you must configure second route-map section with an explicit match specified.
In the following example, routes that have their next hop out Ethernet interface 0 will be distributed:
route-map name
match interface ethernet 0
route-map
set
Use the match ip address route-map configuration command to distribute any routes that have a destination network number address that is permitted by a standard access list. Use the no form of this command to remove the match ip address entry.
match ip address access-list-number...access-list-number| access-list-number | One or more numeric identifiers of access lists. An integer from 1 through 99. |
No access list numbers are specified.
Route-map configuration
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands may be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want o modify only some data, you must configure second route-map section with an explicit match specified.
In the following example, routes that have addresses specified by access list numbers 5 and 80 will be distributed:
route-map name
match ip address 5 80
route-map
set
Use the match ip next-hop route-map configuration command to redistribute any routes that have a next-hop communication server address passed by one of the access lists specified. Use the no form of this command to remove the next-hop entry.
match ip next-hop access-list-number...access-list-number| access-list-number | Number of an access list. It can be an integer from 1 through 99. |
Routes are distributed freely, without being required to match a next-hop address.
Route-map configuration
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands may be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want o modify only some data, you must configure second route-map section with an explicit match specified.
In the following example, routes that have a next-hop communication server address passed by access list 5 or 80 will be distributed:
route-map name
match ip next-hop 5 80
route-map
set
Use the match ip route-source route-map configuration command for any routes that have been advertised by communication servers at the address specified by the access lists. Use the no form of this command to remove the route-source entry.
match ip route-source access-list-number...access-list-number| access-list-number | Number of an access list. It can be an integer from 1 through 99. |
No filtering on route source.
Route-map configuration
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria-- the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands may be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want o modify only some data, you must configure second route-map section with an explicit match specified.
There are situations in which a route's next hop and source communication server address are not the same.
In the following example, routes that have been advertised by communication servers at the addresses specified by access lists 5 and 80 will be distributed:
route-map name
match ip route-source 5 80
route-map
set
Use the match metric route-map configuration command for any routes with the metric specified. Use the no form of this command to remove the entry.
match metric metric-value| metric-value | Route metric. This may be an IGRP five-part metric. A metric value from 0 through 4294967295. |
No filtering on a metric value.
Route-map configuration
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands may be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want o modify only some data, you must configure second route-map section with an explicit match specified.
In the following example, routes with the metric 5 will be redistributed.
route-map name
match metric 5
route-map
set
Use the match route-type route-map configuration command for any routes that are of the specified type. Use the no form of this command to remove the route-type entry.
match route-type {internal | external}| internal | OSPF intra-area and interarea routes or Enhanced IGRP internal routes |
| external | OSPF external type-1 or type-2 routes, or Enhanced IGRP external routes |
Disabled
Route-map configuration
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands may be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure second route-map section with an explicit match specified.
In the following example, internal routes will be redistributed:
route-map name
match route-type internal
route-map
set
Use the match tag command for any routes stored in the routing table with one of the tags specified. Use the no form of this command to remove the tag entry.
match tag tag-value...tag-value| tag-value | List of one or more route tag values. An integer from 0 through 4294967295. |
No match tag values are defined.
Route-map configuration
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The match route-map configuration command has multiple formats. The match commands may be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want o modify only some data, you must configure second route-map section with an explicit match specified.
In the following example, routes stored in the routing table with tag 5 will be redistributed:
route-map name
match tag 5
route-map
set
To trace a branch of a multicast tree for a specific group, use the mbranch EXEC command.
mbranch {group-address | group-name} branch-address [ttl]| group-address | Address of the multicast group. This is a multicast IP address in four-part dotted notation. |
| group-name | Name of the multicast group, as defined in the DNS hosts table or with the ip host command. |
| branch-address | Address of a communication server that is on the tree branch. This is a unicast IP address in four-part dotted notation. |
| ttl | (Optional) Time-to-live value, in hops, that is used in trace request packets sent to the branch communication server. The default value is 30. |
EXEC
The mbranch command sends multicast IGMP trace request packets to the specified branch communication server. It displays information about the branch starting with the local (requesting) communication server and ending with the branch communication server. This is considered to be the forward direction.
The information returned shows how a multicast packet sourced by this communication server will be forwarded by each communication server on the path to the communication server with the branch address.
The communication server with the address branch-address is the only communication server that responds to the trace request packets. The response is unicast to the source.
It is important to specify a value for the ttl argument if you are tracing through a communication server on which a multicast threshold has been set with the ip multicast-threshold interface configuration command.
The following is sample output from the mbranch command. This trace is between the same communication servers as shown in the example for the mrbranch command. Note the order of responses. Also note that the outgoing interface list is the same.
PIM2# mbranch 224.0.255.2 198.92.118.2
Type escape sequence to abort.
Tracing route to group CBONE-WB (224.0.255.2) to 198.92.118.2
Response from 10.17.118.10, 76 msec
1 PIM9 (10.1.22.9) <- PIM2 (10.1.37.2)
Interface list: 131.108.62.0/24 131.108.22.0/24 10.7.0.0/16
2 PIM-CR (131.108.62.18) <- PIM9 (131.108.62.52)
Interface list: 131.108.20.0/24 131.108.53.0/24 131.108.50.0/24
10.16.0.0/16 10.17.0.0/16
3 10.17.118.10 <- 10.17.20.31
Interface list: 198.92.118.0/26 198.92.118.192/26
Table 18-3 describes the fields shown in the display.
| Field | Description |
|---|---|
| Response from 10.17.118.10 | Address of the communication server from which the response to the trace request packets came. This is a different interface on the communication server to which you sent the packet. |
| 76 msec | How long it took to receive the response. |
| 1 | Order number of communication servers in the trace path. In this example, the request went through 3 communication servers to reach the communication server that responded to the request. |
| PIM9 (10.1.22.9) <- PIM2 (10.1.37.2) | Route of the trace request. In this example, the request went from the communication server PIM2 to the communication server PIM9 (PIM2 is considered to be PIM9's RPF neighbor), then from PIM9 to PIM-CR, and finally to the communication server at 10.17.118.10. |
| Interface list: 131.108.62.0/24 131.108.22.0/24 10.7.0.0/16 | Interfaces out which a multicast packet forwarded by the communication server listed on the right side of the previous line (here, PIM2) will be forwarded. In this example, you interpret this line as follows: When the trace packet reached PIM9, it was replicated three times and one copy was sent out each of the three interfaces listed (131.108.62.0, 131.108.22.0, and 10.7.0.0). The interface list shows the subnet number and the mask rather than the interface name. This allows you to more easily figure out the packet's path because you can connect all like-numbered subnets together as a tree in order to detect loops. The source of the multicast packet is always the address of the communication server that started the mbranch (in this case, 10.1.37.2). The list does not include interfaces that failed access list conditions or TTL threshold criteria. |
ip multicast-threshold
mbranch
Use the metric holddown router configuration command to keep new IGRP routing information from being used for a certain period of time. Use the no form of this command to disable metric holddown.
metric holddownThis command has no arguments or keywords.
Disabled
Router configuration
Holddown keeps new routing information from being used for a certain period of time. This can prevent routing loops caused by slow convergence. It is sometimes advantageous to disable holddown to increase the network's ability to quickly respond to topology changes; this command provides this function.
Use the metric holddown command if other communication servers within the IGRP autonomous system are not configured with no metric holddown. If all communication servers are not configured the same way, you increase the possibility of routing loops.
The following example disables metric holddown:
router igrp 15
network 131.108.0.0
network 192.31.7.0
no metric holddown
metric maximum-hops
metric weights
timers basic
Use the metric maximum-hops router configuration command to cause the IP routing software to advertise as unreachable those routes with a hop count higher than is specified by the command (IGRP only). Use the no form of this command to reset the value to the default.
metric maximum-hops hops| hops | Maximum hop count (in decimal). The default value is 100 hops; the maximum number of hops that can be specified is 255. |
100 hops
Router configuration
This command provides a safety mechanism that breaks any potential count-to-infinity problems. It causes the IP routing software to advertise as unreachable routes with a hop count greater than the value assigned to the hops argument.
In the following example, a communication server in autonomous system 71 attached to network 15.0.0.0 wants a maximum hop count of 200, doubling the default. The network administrators decided to do this because they have a complex WAN that can generate a large hop count under normal (nonlooping) operations.
router igrp 71
network 15.0.0.0
metric maximum-hops 200
metric holddown
metric weights
Use the metric weights router configuration command to allow the tuning of the IGRP metric calculations. Use the no form of this command to reset the values to their defaults.
metric weights tos k1 k2 k3 k4 k5| tos | Type of service. Currently it must always be zero. |
| k1-k5 | Constants that convert an IGRP metric vector into a scalar quantity. |
tos=0
k1 = 1
k2 = 0
k3 = 1
k4 = 0
k5 = 0
Router configuration
Use this command to alter the default behavior of IGRP routing and metric computation and allow the tuning of the IGRP metric calculation for a particular type of service (TOS).
If k5 equals 0, the composite IGRP metric is computed according to the following formula:
metric = [k1 * bandwidth + (k2 * bandwidth)/(256 - load) + k3 * delay]
If k5 does not equal zero, an additional operation is done:
metric = metric * [k5 / (reliability + k4)]
Bandwidth is inverse minimum bandwidth of the path in bits per second scaled by a factor of 10*1010. The range is from a 1200 bps line to 10 Gbps.
Delay is in units of 10 microseconds. This gives a range of 10 microseconds to 168 seconds. A delay of all ones indicates that the network is unreachable.
The delay parameter is stored in a 24-bit field, in tens of microseconds. Hence, the delay can be from 1 (10 microseconds) to hex FFFFFF (decimal 16777215), which corresponds to 167.77215 seconds. A delay of all ones (that is, a delay of 16777215) indicates that the network is unreachable.
Table 18-4 lists the default values used for several common media.
| Media Type | Delay | Bandwidth |
|---|---|---|
| Satellite | 200,000 (2 sec) | 20 (500 Mbit) |
| Ethernet | 100 (1 ms) | 1,000 |
| 1.544 Mbps | 2000 (20 ms) | 6,476 |
| 64 kbps | 2000 | 156,250 |
| 56 kbps | 2000 | 178,571 |
| 10 kbps | 2000 | 1,000,000 |
| 1 kbps | 2000 | 10,000,000 |
Reliability is given as a fraction of 255. That is, 255 is 100 percent reliability or a perfectly stable link.
Load is given as a fraction of 255. A load of 255 indicates a completely saturated link.
The following example sets the metric weights to slightly different values than the defaults:
router igrp 109
network 131.108.0.0
metric weights 0 2 0 2 0 0
A dagger (+) indicates that the command is documented in another chapter.
bandwidth +
delay +
metric holddown
metric maximum-hops
To trace a branch of a multicast tree for a group in the reverse direction, use the mrbranch EXEC command.
mrbranch {group-address | group-name} branch-address [ttl]| group-address | Address of the multicast group. This is a multicast IP address in four-part dotted notation. |
| group-name | Name of the multicast group, as defined in the DNS hosts table or with the ip host command. |
| branch-address | Address of a communication server on the tree branch. This is a unicast IP address in four-part dotted notation. |
| ttl | (Optional) Time-to-live value, in hops, that is used in trace request packets sent to the branch communication server. The default value is 30. |
EXEC
The mrbranch command sends trace request packets to the specified branch communication server. Queries are sent recursively to all the communication servers in the branch. This command displays information about the branch starting with the communication server farthest away and working towards the requesting communication server. This is considered to be the reverse direction.
The information returned shows how a multicast packet sourced by this communication server will be forwarded by each communication server along the branch.
The communication server with the address branch-address responds to the trace request packets. The requesting communication server then sends a query to the communication server that is the first communication server's RPF neighbor. Both the request and response packets have unicast addresses.
The number of packets generated by this command is two times the number of communication servers between the source communication server and the specified branch communication server.
The following is sample output from the mrbranch command. This example is between the same communication server as shown in the mbranch command. Note the order of the responses. Also note that the outgoing interface list is the same.
PIM2# mrbranch 224.0.255.2 10.17.118.10
Type escape sequence to abort.
Tracing route to group CBONE-WB (224.0.255.2) from 10.17.118.10
Response from 10.17.118.10, 68 msec
1 10.17.118.10 <- 10.17.20.31
Interface list: 198.92.118.0/26 198.92.118.192/26
Response from PIM-CR (131.108.62.18), 12 msec
1 PIM-CR (131.108.62.18) <- PIM9 (131.108.62.52)
Interface list: 131.108.20.0/24 131.108.53.0/24 131.108.50.0/24
10.16.0.0/16 10.17.0.0/16
Response from PIM9 (131.108.62.52), 8 msec
1 PIM9 (131.108.62.52) <- PIM2 (10.1.37.2)
Interface list: 131.108.22.0/24 131.108.62.0/24 10.7.0.0/16
Table 18-5 describes the fields shown in the display.
| Field | Description |
|---|---|
| Tracing route to group CBONE-WB (224.0.255.2) from 10.17.118.10 | Route that is being traced. |
| 68 msec | How long it took to receive the response. |
| Response from 10.17.118.10 | Address of the communication server from which the response to the trace request packets came. |
| 1 | Order number of communication servers in the trace path. |
| 10.17.118.10 <- 10.17.20.31 | RPF (reverse path forwarding) neighbor information. The first response in this example indicates that a multicast packet sent from the communication server PIM2 will be received on interface 10.17.118.10. This multicast packet should have been forwarded from 10.17.20.31 because that is the address that this communication server would use as the next-hop communication server (found in the IP routing table) to send a unicast packet back to the original source (PIM2) of the multicast packet. |
| Interface list: 198.92.118.0/26 198.92.118.192/26 | Interfaces out which a multicast packet from the communication server listed on the right side of the previous line (here, for the group 224.0.255.2 that had been forwarded by 10.17.20.31) will be forwarded. The list does not include interfaces that failed access list conditions or TTL threshold criteria. |
mbranch
show ip mroute
To trace the entire multicast tree for the specified group, use the mtrace user EXEC command.
mtrace {group-address | group-name} [ttl]| group-address | Address of the multicast group. This is a multicast IP address in four-part dotted notation. |
| group-name | Name of the multicast group, as defined in the DNS hosts table or with the ip host command. |
| ttl | (Optional) Time-to-live value. Communication servers at a distance of ttl hops from the local communication server respond with a record of the path to each of them. The ttl argument can be a number from 0 to 32. The default value is 1, which generates responses from all communication servers directly connected to the local communication server. |
EXEC
The trace request generated by the mtrace command is multicast to the multicast group. Responses are unicast to the source communication server.
Responses are delayed by the responders.
The following is sample output from the mtrace command:
cs> mtrace 224.0.255.1
Type escape sequence to abort.
Tracing route to group CBONE-AUDIO (224.0.255.1)
Response from PIM4 (198.92.36.131), 7 msec
1 PIM4 (198.92.36.131) <- 0.0.0.0
Interface list: 198.92.37.0/24 10.20.0.0/16
Response from PIM3 (198.92.36.130), 4 msec
1 PIM3 (198.92.36.130) <- 0.0.0.0
Interface list: 198.92.35.160/27
Response from PIM4 (198.92.37.33), 2 msec
1 PIM4 (198.92.37.33) <- 0.0.0.0
Interface list: 10.20.0.0/16
Response from PIM9 (10.1.22.9), 20 msec
1 PIM9 (10.1.22.9) <- PIM2 (10.1.37.2)
Interface list: 131.108.62.0/24 131.108.22.0/24 10.7.0.0/16
Response from ITCHY (198.92.37.2), 3 msec
1 ITCHY (198.92.37.2) <- 0.0.0.0
Interface list: Null
Table 18-6 describes the fields shown in the display.
| Field | Description |
|---|---|
| Tracing route to group CBONE-AUDIO (224.0.255.1) | Name and address of group for which routes are being traced. |
| Response from PIM4 (198.92.37.33) | Address of the communication server from which the response to the trace request packets came. |
| 7msec | How long it took to receive the response. |
| Interface list: 198.92.37.0/24 10.20.0.0/16 | Interface out which a multicast packet from the communication server listed on the right side of the previous line will be forwarded. |
mbranch
mrbranch
Use this form of the neighbor router configuration command to define a neighboring communication server with which to exchange routing information. Use the no form of this command to remove an entry.
neighbor ip-address| ip-address | IP address of a peer communication server with which routing information will be exchanged |
No neighboring communication servers are defined.
Router configuration
For exterior routing protocol EGP, this command specifies routing peers. For normally broadcast protocols such as IGRP or RIP, this command permits the point-to-point (nonbroadcast) exchange of routing information. When used in combination with the passive-interface router configuration command, routing information can be exchanged between a subset of communication servers on a LAN.
Multiple neighbor commands can be used to specify additional neighbors or peers.
OSPF has its own version of the neighbor command. See the neighbor (OSPF) command page in this chapter.
The following example establishes an EGP neighbor:
autonomous-system 109
router egp 110
neighbor 131.108.1.1
In the following example, IGRP updates are sent to all interfaces on network 131.108.0.0 except Ethernet interface 1. However, in this case a neighbor router configuration command is included. This command permits the sending of routing updates to specific neighbors. One copy of the routing update is generated per neighbor.
router igrp 109
network 131.108.0.0
passive-interface ethernet 1
neighbor 131.108.20.4
passive-interface
Use this form of the neighbor router configuration command to configure OSPF communication servers interconnecting to nonbroadcast networks. Use the no form of this command with the appropriate IP address and arguments to remove the configuration.
neighbor ip-address [priority number] [poll-interval seconds]| ip-address | Interface IP address of the neighbor. |
| priority number | (Optional) 8-bit number indicating the communication server priority value of the nonbroadcast neighbor associated with the IP address specified. The default is 0. |
| poll-interval seconds | (Optional) Unsigned integer value reflecting the poll interval. RFC 1247 recommends that this value should be much larger than the Hello interval. The default is 2 minutes (120 seconds). |
No configuration is specified.
Router configuration
X.25 and Frame Relay provide an optional broadcast capability that can be configured in the map to allow OSPF to run as a broadcast network. At the OSPF level you can configure the communication server as a broadcast network. See the x25 map and frame-relay map interface configuration command descriptions in "X.25 Commands" and "Frame Relay Commands" chapters, respectively, of this manual for more detail.
One neighbor entry must be included in the communication server's configuration for each known nonbroadcast network neighbor. The neighbor address has to be on the primary address of the interface.
If a neighboring communication server has become inactive (Hello packets have not been seen for the Router DeadInterval period), it may still be necessary to send Hello packets to the dead neighbor. These Hello packets will be sent at a reduced rate called Poll Interval.
When the communication server first starts up, it sends only Hello packets to those communication servers with non-zero priority, that is, communication servers that are eligible to become designated routers and backup designated routers. After designated routers and backup designated routers are selected, they will then start sending Hello packets to all neighbors in order to form adjacencies.
The following example declares a communication server at address 131.108.3.4 on a nonbroadcast network, with a priority of 1 and a poll-interval of 180:
router ospf
neighbor 131.108.3.4 priority 1 poll-interval 180
ip ospf priority
Use the neighbor advertisement-interval router configuration command to set the minimum interval between sending BGP routing updates. Use the no form of this command to remove an entry.
neighbor {address | tag} advertisement-interval seconds| address | Neighbor address. |
| tag | Neighbor tag. |
| seconds | Time in seconds. Integer from 0 through 600. |
30 seconds for external peers and 5 seconds for internal peers.
Router configuration
In the following example, the minimum time between sending BGP routing updates is set to
10 seconds:
router bgp 5
neighbor 4.4.4.4 advertisement-interval 10
Use the neighbor any router configuration command to control how neighbor entries are added to the routing table for both EGP and BGP. Use the no form of this command to remove the configuration.
neighbor any [access-list-number]| access-list-number | (Optional) Access list number the neighbor must be accepted by to be allowed to peer with the EGP or BGP process. If no list is specified, any neighbor will be allowed to peer with the communication server. |
No configuration is specified.
Router configuration
The following example configuration illustrates the use of the neighbor any command in conjunction with the access-list global configuration command:
access-list 1 permit 10.0.0.0 0.255.255.255
! global access list assignment
router egp 0
neighbor any 1
A dagger (+) indicates that the command is documented in another chapter.
access-list +
neighbor any third-party
router egp 0
Use the neighbor any third-party router configuration command to configure an EGP process that determine which neighbors will be treated as the next hop in EGP advertisements. Use the no form of this command to remove the configuration.
neighbor any third-party ip-address [internal | external]| ip-address | IP address of the third-party communication server that is to be the next hop in EGP advertisements. |
| internal | (Optional) Indicates that the third-party communication server should be listed in the internal section of the EGP update. |
| external | (Optional) Indicates that the third-party communication server should be listed in the external section of the EGP update. |
No EGP process is configured.
Router configuration
The following example specifies the particular neighbors that an EGP process will view as peers:
access-list 2 permit 10.0.0.0 0.255.255.255
! global access list assignment
router egp 0
neighbor any 2
neighbor any third-party 10.1.1.1
neighbor any
router egp 0
Use the neighbor configure-neighbors router configuration command to instruct the communication server to treat temporary neighbors that have been accepted by a template as if they had been configured by hand. The no form of this command causes any new neighbor accepted by the template to be treated as temporary.
neighbor template-name configure-neighbors| template-name | A user selectable designation that identifies a particular template (an arbitrary word) |
New neighbors are treated as temporary.
Router configuration
Under normal circumstances, neighbors that are allowed to connect to the communication server because you had configured a template are treated as temporary. When a temporary neighbor disconnects, the local communication server will not try to actively reestablish a connection with it. In addition, information about temporary neighbors will not show up in the communication server configuration (write terminal).
When configure-neighbors is enabled on a particular template, any neighbor accepted by that template will be treated as if it had been manually configured. These neighbors will show up in write terminal displays and will be written to the nonvolatile configuration if a write memory command is issued.
In the following example, any BGP speaker matching access-list 7 can connect to the communication server and exchange information. Any neighbor that connects will be treated as if it had been manually configured.
access-list 7 permit 168.89.3.0 0.0.0.255
neighbor internal-ethernet neighbor-list 7
neighbor internal-ethernet configure-neighbors
neighbor neighbor-list
Use the neighbor distribute-list router configuration command to distribute BGP neighbor information as specified in an access list. Use the no form of this command to remove an entry.
neighbor ip-address distribute-list access-list-number {in | out}| ip-address | Neighbor's IP address. |
| access-list-number | Predefined access list number. Only standard access lists can be used with this command. |
| in | Access list is applied to incoming advertisements to that neighbor. |
| out | Access list is applied to outgoing advertisements from that neighbor. |
No BGP neighbor is specified.
Router configuration
Using distribute lists is one of two ways to filter BGP advertisements. The other way is to use autonomous system-path filters, as with the ip as-path access-list global configuration command and the neighbor
filter-list command.
The following example applies list 39 to incoming advertisements to neighbor 120.23.4.1:
router bgp 109
network 131.108.0.0
neighbor 120.23.4.1 distribute-list 39 in
ip as-path access-list
neighbor filter-list
Use the neighbor ebgp-multihop router configuration command to accept and attempt BGP connections to external peers residing on networks that are not directly connected. Use the no form of this command to return to the default of allowing only directly connected neighbors.
neighbor ip-address ebgp-multihop| ip-address | IP address of the BGP-speaking neighbor. |
Only directly connected neighbors are allowed.
Router configuration
This feature should only be used under the guidance of technical support staff.
The following example allows connections to or from neighbor 131.108.1.1, which resides on a network that is not directly connected:
router bgp 109
neighbor 131.108.1.1 ebgp-multihop
Use the neighbor filter-list router configuration command to set up BGP filters, using access lists defined with the ip as-path access-list command. Use the no form of this command to disable this function.
neighbor ip-address filter-list access-list-number {in | out | weight weight}| ip-address | IP address of the neighbor. |
| access-list-number | Predefined autonomous system path access list number. |
| in | Access list to incoming routes. |
| out | Access list to outgoing routes. |
| weight weight | Assigns a relative importance to incoming routes matching autonomous system paths. Acceptable values are 0 to 65535. |
Disabled
Router configuration
This command establishes filters on both inbound and outbound BGP routes. Any number of weight filters are allowed on a per-neighbor basis, but only one in or out filter is allowed. The weight of a route affects BGP's route-selection rules.
The implemented weight is based on the first matched autonomous system path. Weights indicated when an autonomous system path is matched override the weights assigned by global neighbor commands. In other words, the weights assigned with the match as-path and set weight route-map commands override the weights assigned using the neighbor weight and neighbor filter-list commands.
See the "Regular Expressions" appendix for information on forming regular expressions.
In the following example, the BGP neighbor with IP address 128.125.1.1 is not sent advertisements about any path through or from the adjacent autonomous system 123:
ip as-path access-list 1 deny _123_
ip as-path access-list 1 deny ^123 .*
! The space in the above expression (^123 .*)is required.
router bgp 109
network 131.108.0.0
neighbor 129.140.6.6 remote-as 123
neighbor 128.125.1.1 remote-as 47
neighbor 128.125.1.1 filter-list 1 out
ip as-path access-list
neighbor distribute-list
neighbor weight
Use the neighbor neighbor-list router configuration command to configure BGP to support anonymous neighbor peers by configuring a neighbor template. Use the no form of this command to delete the template, and also cause any temporary neighbors accepted by the template to be shut down and removed.
neighbor template-name neighbor-list access-list-number| template-name | A user selectable designation that identifies a particular template (an arbitrary word). |
| access-list-number | An IP access list number in the range 1 through 99. |
No configuration is defined.
Router configuration
To specify a group of anonymous neighbors, configure a neighbor template rather than specifically configure each neighbor. The template allows you to specify an IP access list which defines remote systems that can establish a BGP connection to the communication server. External BGP peers must be on a directly connected Ethernet unless they are overridden by the neighbor ebgp-multihop command.
Once you specify a template, you configure the template as if it were a regular neighbor entry, such as setting the protocol version or filter lists, so that anonymous neighbors accepted by the template will receive the settings of the template.
These neighbors accepted by the template appear in the show ip bgp summary and show ip bgp neighbor displays, although they do not appear in the communication server configuration. When the session is disconnected, all knowledge about the neighbor is discarded and the communication server will not attempt to actively re-establish a connection.
You can use the neighbor configure-neighbors command to request that the communication server treat peers learned through a template as if they were manually configured neighbors. These peers will then show up in write terminal displays and can be stored as part of the nonvolatile configuration.
In the following example, any BGP speaker from 168.89.3.0 can connect to the communication server and exchange information:
access-list 7 permit 168.89.3.0 0.0.0.255
neighbor internal-ethernet neighbor-list 7
neighbor internal-ethernet configure-neighbors
In the following example, any BGP speaker in the connected internet can establish a BGP connection to the local communication server, and the local communication server will send them routing information. However, the distribute-list clause instructs the local communication server to ignore all information these remote BGP speakers send to it.
access-list 9 permit 0.0.0.0 255.255.255.255
access-list 10 deny 0.0.0.0 255.255.255.255
neighbor route-server-peers neighbor-list 9
neighbor route-server-peers distribute-list 10 in
access-list (standard)
neighbor configure-neighbors
neighbor ebgp-multihop
Use the neighbor next-hop-self router configuration command to configure the communication server to disable next-hop processing on BGP updates. Use the no form of this command to disable this feature.
neighbor ip-address next-hop-self| ip-address | IP address of the BGP-speaking neighbor |
Disabled
Router configuration
This command is useful in nonmeshed networks such as Frame Relay or X.25 where BGP neighbors may not have direct access to all other neighbors on the same IP subnet.
The following example forces all updates destined for 131.108.1.1 to advertise this communication server as the next hop:
router bgp 109
neighbor 131.108.1.1 next-hop-self
Use the neighbor remote-as router configuration command to add an entry to the BGP neighbor table. Use the no form of this command to remove a neighbor.
neighbor ip-address remote-as number| ip-address | Neighbor's IP address |
| number | Autonomous system to which the neighbor belongs |
There are no BGP neighbor peers.
Router configuration
Specifying a neighbor with an autonomous system number that matches the autonomous system number specified in the router bgp global configuration command identifies the neighbor as internal to the local autonomous system. Otherwise, the neighbor is considered external.
The following example specifies that the communication server at the address 131.108.1.2 is a neighbor in autonomous system number 109:
router bgp 110
network 131.108.0.0
neighbor 131.108.1.2 remote-as 109
In the following example, a BGP communication server is assigned to autonomous system 109, and two networks are listed as originating in the autonomous system. Then the addresses of three remote communication servers (and their autonomous systems) are listed. The communication server being configured will share information about networks 131.108.0.0 and 192.31.7.0 with the neighbor communication servers. The first communication server listed is in the same Class B network address space, but in a different autonomous system; the second neighbor command illustrates specification of an internal neighbor (with the same autonomous system number) at address 131.108.234.2; and the last neighbor command specifies a neighbor on a different network.
router bgp 109
network 131.108.0.0
network 192.31.7.0
neighbor 131.108.200.1 remote-as 167
neighbor 131.108.234.2 remote-as 109
neighbor 150.136.64.19 remote-as 99
Use the neighbor route-map router configuration command to apply a route map to incoming or outgoing routes. Use the no form of this command to remove the entry.
neighbor {address | tag} route-map route-map-name {in | out}| address | Neighbor's IP address |
| tag | Neighbor tag |
| route-map-name | Name of route map |
| in | Apply to incoming routes |
| out | Apply to outgoing routes |
No route maps are applied to a peer.
Router configuration
If an outbound route map is specified, it is proper behavior to only advertise routes that match at least one section of the route map.
In the following example, route map "internal-map" is applied to incoming route from 198.92.70.24:
router bgp 5
neighbor 198.92.70.24 route-map internal-map in
!
route-map internal-map
match as-path 1
set local-preference 100
Use the neighbor third-party router configuration command to send updates regarding EGP third-party communication servers. Use the no form of this command to disable these updates.
neighbor ip-address third-party third-party-ip-address [internal | external]| ip-address | IP address of the EGP peer. |
| third-party-ip-address | Address of the third-party communication server on the network shared by the Cisco communication server and the EGP peer specified by address. |
| internal | (Optional) Indicates that the third-party communication server should be listed in the internal section of the EGP update. This is the default. |
| external | (Optional) Indicates that the third-party communication server should be listed in the external section of the EGP update. |
Disabled
Router configuration
Using this third-party mechanism, EGP tells its peer that another communication server (the third party) on the shared network is the appropriate communication server for some set of destinations. If updates mentioning third-party communication servers are desired, use this command.
All networks reachable through the third-party communication server will be listed in the EGP updates as reachable by the communication server. The optional internal and external keywords indicate whether the third-party communication server should be listed in the internal or external section of the EGP update. Normally, all networks are mentioned in the internal section.
This command can be used multiple times to specify additional third-party communication servers.
In the following example, routes learned from communication server 131.108.6.99 will be advertised to 131.108.6.5 as third-party internal routes:
neighbor 131.108.6.5 third-party 131.108.6.99 internal
In the following example, routes learned from 131.108.6.100 will be advertised to 131.108.6.5 as third-party external routes:
neighbor 131.108.6.5 third-party 131.108.6.100 external
Use the neighbor update-source router configuration command to configure the communication server to allow internal BGP sessions to use any operational interface for TCP connections. Use the no form of this command to restore the interface assignment to the closest interface, also called the
best-local-address.
| ip-address | IP address of the BGP-speaking neighbor |
| interface | Loopback interface |
Best-local-address
Router configuration
This feature works in conjunction with the Loopback interface feature described in the "Configuring Interfaces" chapter of the Access and Communication Servers Configuration Guide.
In the following example, BGP TCP connections for the specified neighbor will be sourced with Loopback interface's IP address rather than the best-local-address:
router bgp 110
network 160.89.0.0
neighbor 160.89.2.3 remote-as 110
neighbor 160.89.2.3 update-source Loopback0
Use the neighbor version router configuration command to configure the communication server to accept only a particular version. Use the no form of this command to return the version to the default level of that neighbor.
neighbor ip-address version value| ip-address | IP address of the BGP-speaking neighbor. |
| value | Version number. The version can be set to 2 to force the communication server to only use Version 2 with the specified neighbor. The default is to use Version 4 of BGP and dynamically negotiate down to Version 2 if requested. |
Version 4
Router configuration
Entering this command disables dynamic version negotiation.
Our implementation of BGP supports Versions 2, 3, and 4 of BGP. If the neighbor does not accept default version 4, dynamic version negotiation is implemented to negotiate down to version 2.
The following example locks down to Version 4 of the BGP protocol:
router bgp 109
neighbor 131.104.27.2 version 4
Use the neighbor weight router configuration command to specify a weight to assign to a specific neighbor connection. Use the no form of this command to remove the assignment.
neighbor ip-address weight weight| ip-address | Neighbor's IP address. |
| weight weight | Weight to assign. Acceptable values are 0 to 65535. |
Routes learned through another BGP peer have a default weight of 0 and routes sourced by the local communication server have a default weight of 32768.
Router configuration
All routes learned from this neighbor will have the assigned weight initially. The route with the highest weight will be chosen as the preferred route when multiple routes are available to a particular network.
The weights assigned with the match as-path and set weight route-map commands override the weights assigned using the neighbor weight and neighbor filter-list commands.
The following example sets the weight of all routes learned via 151.23.12.1 to 50:
router bgp 109
neighbor 151.23.12.1 weight 50
neighbor distribute-list
neighbor filter-list
Use this form of the network router configuration command to specify the list of networks for the BGP routing process. Use the no form of this command to remove the entry.
network network-number mask network-mask| network-number | IP address of a peer communication server with which routing information will be exchanged |
| mask | Network or subnetwork mask |
| network-mask | Network mask address |
No networks are specified.
Router configuration
These types of networks can be learned from connected routes, dynamic routing, and from static route sources.
A maximum of 200 network commands may be specified for a single BGP process.
The following example sets up network 131.108.1.27 to be included in the communication server's BGP updates:
router bgp 120
network 131.108.1.27 mask 255.255.255.0
network backdoor
network mask
network weight
router bgp
Use this form of the network router configuration command to specify the list of networks for the EGP routing process. Use the no form of this command to remove a network from the list.
network network-number| network-number | IP address of a peer communication server with which routing information will be exchanged |
No networks are specified.
Router configuration
The networks to be advertised to the EGP peers of an EGP routing process are advertised with a distance of zero. The restrictions on the network you specify are that it must appear in the routing table, and the network number must not contain any subnet information. The network can be connected, statically configured, or redistributed into EGP from other routing protocols. Multiple commands can be used to specify additional networks.
The following example illustrates a typical configuration for an EGP communication server process. The communication server is in autonomous system 109 and is peering with communication servers in autonomous system 164. It will advertise the networks 131.108.0.0 and 192.31.7.0 to the communication server in autonomous system 164, 10.2.0.2. The information sent and received from peer communication servers can be filtered in various ways, including blocking information from certain communication servers and suppressing the advertisement of specific routes.
autonomous-system 109
router egp 164
network 131.108.0.0
network 192.31.7.0
neighbor 10.2.0.2
router egp
To specify a list of networks for the IP Enhanced IGRP routing process, use the network router configuration command. To remove a network from the list, use the no form of this command.
network network-number| network-number | IP address of the directly connected network |
Disabled
Router configuration
The network number must not contain any subnet information. You can specify multiple network commands.
IP Enhanced IGRP sends updates to the interfaces in the specified network(s). Also, if you do not specify an interface's network, it will not be advertised in any IP Enhanced IGRP updates.
The following example configures a communication server for IP Enhanced IGRP and assigns autonomous system number 109. The network commands indicate the networks directly connected to the communication server.
router eigrp 109
network 131.108.0.0
network 192.31.7.0
router eigrp
Use this form of the network router configuration command to specify a list of networks for the IGRP routing process. Use the no form of this command to remove a network from the list.
network network-number| network-number | IP address of the directly connected networks |
No networks are specified.
Router configuration
The network number specified must not contain any subnet information. You can specify multiple network commands.
IGRP sends updates to the interfaces in the specified network(s). Also, if an interface's network is not specified, it will not be advertised in any IGRP update.
The following example configures a communication server for IGRP and assigns autonomous system 109. The network commands indicate the networks directly connected to the communication server.
router igrp 109
network 131.108.0.0
network 192.31.7.0
router igrp
Use this form of the network router configuration command to specify a list of networks for the RIP routing process. Use the no form of this command to remove a network from the list.
network network-number| network-number | IP address of the network of directly connected networks. |
No networks are specified.
Router configuration
The network number specified must not contain any subnet information. You can specify multiple network commands. RIP routing updates will be sent and received only through interfaces on this network.
RIP sends updates to the interfaces in the specified networks. Also, if an interface's network is not specified, it will not be advertised in any RIP update.
The following example defines RIP as the routing protocol to be used on all interfaces connected to networks 128.99.0.0 and 192.31.7.0:
router rip
network 128.99.0.0
network 192.31.7.0
router rip
Use the network area router configuration command to define the interfaces on which OSPF runs and to define the area ID for those interfaces. Use the no form of this command to disable OSPF routing for interfaces defined with the address wildcard-mask pair; you must specify the complete address range and area ID.
network address wildcard-mask area area-id| address | IP address. |
| wildcard-mask | IP-address-type mask that includes "don't care" bits. |
| area-id | Area that is to be associated with the OSPF address range. It can be specified as either a decimal value or as an IP address. If you intend to associate areas with IP subnets, you can specify a subnet address as the area-id. |
Disabled
Router configuration
The address and wildcard-mask arguments together allow you to define one or multiple interfaces to be associated with a specific OSPF area using a single command. Using the wildcard-mask allows you to define one or multiple interfaces to be associated with a specific OSPF area using a single command. If you intend to associate areas with IP subnets, you can specify a subnet address as the area-id.
The communication server sequentially evaluates the address/wildcard-mask pair for each interface as follows:
In the following partial example, OSPF routing process 109 is initialized, and four OSPF areas are defined: 10.9.50.0, 2, 3, and 0. Areas 10.9.50.0, 2, and 3 mask specific address ranges, while Area 0 enables OSPF for all other networks.
router ospf 109
network 131.108.20.0 0.0.0.255 area 10.9.50.0
network 131.108.0.0 0.0.255.255 area 2
network 131.109.10.0 0.0.0.255 area 3
network 0.0.0.0 255.255.255.255 area 0
router ospf
Use the network backdoor router configuration command to specify a backdoor route to a BGP border communication server that will provide better information about the network. Use the no form of this command to remove an address from the list.
network address backdoor| address | IP address of the network to which you want a backdoor route |
No network is advertised.
Router configuration
A backdoor network is treated as a local network, except that it is not advertised.
The following example configures network 131.108.0.0 as a local network and network 192.31.7.0 as a backdoor network:
router bgp 109
network 131.108.0.0
network 192.31.7.0 backdoor
Use the network weight router configuration command to assign an absolute weight, or importance, to a BGP network. Use the no form of this command to delete the entry.
network address weight weight| address | IP address of the network. |
| weight weight | Absolute weight. Integer from 0 to 65535. |
Weight is unmodified. Weight is zero if the original default weight has not been modified by other router configuration commands.
Router configuration
The weight specified by this command overrides a weight assigned by the redistribute command.
The following example assigns network 193.0.0.0 an absolute weight of 100:
router bgp 5
network 193.0.0.0 weight 100
Use the offset-list router configuration command to add or remove a positive offset to incoming and outgoing metrics for networks matching a specified access list (for IGRP and RIP only). Use the no form of this command with the appropriate keywords to remove the offset list.
offset-list {in | out} offset [access-list-number]| in | Applies the access list to incoming metrics. |
| out | Applies the access list to outgoing metrics. |
| offset | Positive offset to be applied to metrics for networks matching the access list. If the offset is zero, no action is taken. |
| access-list-number | (Optional) Access list to be applied. If unspecified, the argument supplied to offset is applied to all metrics. If offset is zero, no action is taken. For IGRP, the offset is added to the delay component only. Must be a standard access list. |
Disabled
Router configuration
The offset value is added to the routing metric.
The following example for a communication server using IGRP applies an offset of 10 to its delay component for all outgoing metrics:
offset-list out 10
Use the passive-interface router configuration command to disable sending routing updates on an interface. Use the no form of this command to reenable sending routing updates on the specified interface.
passive-interface type number| type | Interface type |
| number | Interface number |
Routing updates are sent on the interface.
Router configuration
If you disable the sending of routing updates on an interface, the particular subnet will continue to be advertised to other interfaces, and updates from other communication servers on that interface continue to be received and processed.
IP Enhanced IGRP is disabled on an interface that is configured as passive although it advertises the route.
For OSPF, OSPF routing information is neither sent nor received through the specified communication server interface. The specified interface address appears as a stub network in the OSPF domain.
The following example sends IGRP updates to all interfaces on network 131.108.0.0 except Ethernet interface 1:
router igrp 109
network 131.108.0.0
passive-interface ethernet 1
To redistribute routes from one routing domain into another routing domain, use the redistribute router configuration command. To disable redistribution, use the no form of this command.
redistribute protocol [process-id] {level-1 | level-1-2 | level-2} [metric metric-value]Route redistribution is disabled.
protocol--No source protocol is defined.
process-id--No process ID is defined.
metric metric-value--0
metric-type type-value--Type 2 external route
match internal | external--internal
external type-value--internal
tag tag-value--If no value is specified, the remote autonomous system number is used for routes
from BGP and EGP; for other protocols, the default is 0.
route-map map-tag--If the route-map argument is not entered, all routes are redistributed; if no
map-tag value is entered, no routes are imported.
weight weight--No network weight is defined.
subnets--No subnets are defined.
Router configuration
Changing or disabling any keyword will not affect the state of other keywords.
A communication server receiving a link-state protocol (LSP) with an internal metric will consider the cost of the route from itself to the redistributing communication server plus the advertised cost to reach the destination. An external metric only considers the advertised metric to reach the destination.
Routes learned from IP routing protocols can be redistributed at level-1 into an attached area or at level-2. The keyword level-1-2 allows both in a single command.
Redistributed routing information should always be filtered by the distribute-list out router configuration command. This ensures that only those routes intended by the administrator are passed along to the receiving routing protocol.
Whenever you use the redistribute or the default-information router configuration commands to redistribute routes into an OSPF routing domain, a communication server acting as a communication server automatically becomes an Autonomous System Boundary Router (ASBR). However, an ASBR does not, by default, generate a default route into the OSPF routing domain.
When routes are redistributed between OSPF processes, no OSPF metrics are preserved.
The only connected routes affected by this redistribute command are the routes not specified by the network command.
You cannot use the default-metric command to affect the metric used to advertise connected routes.
Default redistribution of IGPs or EGP into BGP is not allowed unless default-information originate is specified.
When routes are redistributed into OSPF and no metric is specified in the metric keyword, the default metric that OSPF uses is 20 for routes from all protocols except BGP route, which gets a metric of 1.
The following are examples of the various configurations you would use to redistribute one routing protocol into another routing protocol.
The following example configuration causes OSPF routes to be redistributed into a BGP domain:
router bgp 109
redistribute ospf...
The following example configuration causes IGRP routes to be redistributed into an OSPF domain:
router ospf 110
redistribute igrp...
The following example causes the specified IGRP process routes to be redistributed into an OSPF domain. The IGRP-derived metric will be remapped to 100 and RIP routes to 200.
router ospf 109
redistribute igrp 108 metric 100 subnets
redistribute rip metric 200 subnets
In the following example, BGP routes are configured to be redistributed into IS-IS. The link-state cost is specified as 5, and the metric type will be set to external, indicating that it has lower priority than internal metrics.
router isis
redistribute bgp 120 metric 5 metric-type external
default-information allowed
distribute-list out
route-map
show route-map
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Use the no form of this command to delete the entry.
route-map map-tag [[permit | deny] | [sequence-number]]| map-tag | Defines a meaningful name for the route map. The redistribute router configuration command uses this name to reference this route map. Multiple route maps may share the same map tag name. |
| permit | (Optional) If the match criteria are met for this route map, and permit is specified, the route is redistributed as controlled by the set actions. If the match criteria are not met, and permit is specified, the next route map with the same map-tag is tested. If a route passes none of the match criteria for the set of route maps sharing the same name, it is not redistributed by that set. |
| deny | (Optional) If the match criteria are met for the route map, and deny is specified, the route is not redistributed, and no further route maps sharing the same map tag name will be examined. |
| sequence-number | (Optional) Number that indicates the position a new route map is to have in the list of route maps already configured with the same name. If given with the no form of this command, it specifies the position of the route map that should be deleted. |
No default available.
Global configuration
Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
Use route maps when you wish to have detailed control over how routes are redistributed between routing processes. The destination routing protocol is the one you specify with the router global configuration command. The source routing protocol is the one you specify with the redistribute router configuration command. See the following example as an illustration of how route maps are configured.
The following example redistributes all OSPF routes into IGRP:
router igrp 109
redistribute ospf 110
default metric 1000 100 255 1 1500
The following example redistributes RIP routes with a hop count equal to 1 into OSPF. These routes will be redistributed into OSPF as external link state advertisements with a metric of 5, metric type of Type 1 and a tag equal to 1.
router ospf 109
redistribute rip route-map rip-to-ospf
route-map rip-to-ospf permit
match metric 1
set metric 5
set metric-type type1
set tag 1
match
redistribute
set
show route-map
Use the router bgp global configuration command to configure the Border Gateway Protocol (BGP) routing process. Use the no form of this command to remove the routing process.
router bgp autonomous-system| autonomous-system | Identifies the communication server to other BGP communication servers and tags the routing information passed along. |
No BGP routing process is enabled by default.
Global configuration
This command allows you to set up a distributed routing core that automatically guarantees the loop-free exchange of routing information between autonomous systems.
The following example configures a BGP process for autonomous system 120:
router bgp 120
neighbor
network (BGP)
timers bgp
Use the router egp global configuration command to configure the Exterior Gateway Protocol (EGP) routing process. Use the no form of this command to turn off the EGP routing process.
router egp remote-as| remote-as | Identifies the autonomous system number the communication server expects its peers to be advertising in their EGP messages. |
No EGP routing process is defined.
Global configuration
You must specify the autonomous system number before starting EGP. The local autonomous system number will be included in EGP messages sent by the communication server. The software does not insist that the actual remote autonomous system number match the configured autonomous system numbers. The output from the debug ip-egp EXEC command will advise of any discrepancies.
The following example assigns a communication server to autonomous system 109 and is peering with communication servers in autonomous system 164:
autonomous-system 109
router egp 164
autonomous-system
neighbor
network (EGP)
timers egp
Use the router egp 0 global configuration command to specify that a communication server should be considered a core gateway. Use the no form of this command to disable this function.
router egp 0This command has no arguments or keywords.
Disabled
Global configuration
Core gateways are central clearinghouses of routing information. Only one core gateway process can be configured in a communication server.
The router egp 0 global configuration command allows a specific communication server to have an EGP process that will enable it to act as a peer with any reachable autonomous system and information is exchanged freely between autonomous systems.
Normally, an EGP process expects to communicate with neighbors from a single autonomous system. Because all neighbors are in the same autonomous system, the EGP process assumes that these neighbors all have consistent internal information. Therefore, if the EGP process is informed about a route from one of its neighbors, it will not send it out to other neighbors.
With core EGP, the assumption is that all neighbors are from different autonomous systems, and all have inconsistent information. In this case, the EGP process distributes routes from one neighbor to all others (but not back to the originator). This allows the EGP process to be a central clearinghouse for information.
To control how an EGP process determines which neighbors will be treated as peers, use the neighbor any router configuration command with the router egp 0 global configuration command.
The following example illustrates how an EGP core gateway can be configured:
access-list 1 permit 10.0.0.0 0.255.255.255
! global access list assignment
router egp 0
neighbor any 1
network 131.108.0.0
neighbor any
neighbor any third-party
To configure the IP Enhanced IGRP routing process, use the router eigrp global configuration command. To shut down the routing process on the specified autonomous system, use the no form of this command.
router eigrp process-number| process-number | Number of a process that identifies the routes to other IP Enhanced IGRP communication servers. It is also used to tag the routing information. If you have an autonomous system number, you can use it for the process number. |
Disabled
Global configuration
The following example shows how to configure an IP Enhanced IGRP routing process and assign autonomous system number 109:
router eigrp 109
network
Use the router igrp global configuration command to configure the Interior Gateway Routing Protocol (IGRP) routing process. Use the no form of this command to shut down the routing process on the specified autonomous system.
router igrp process-number| process-number | Number of a process that identifies the routes to other IP Enhanced IGRP communication servers. It is also used to tag the routing information. If you have an autonomous system number, you can use it for the process number. |
No IGRP routing process is defined.
Global configuration
The following example shows how to configure an IGRP routing process and assign autonomous system 109:
router igrp 109
network (IGRP)
Use the router ospf global configuration command to configure an OSPF routing process on a communication server. Use the no form of this command to terminate an individual OSPF routing process.
router ospf process-id| process-id | Internally used identification parameter for an OSPF routing process. It is locally assigned and can be any positive integer. A unique value is assigned for each OSPF routing process. |
No OSPF routing process is defined.
Global configuration
You can specify multiple OSPF routing processes in each communication server.
The following example shows how to configure an OSPF routing process and assign a process ID of 109:
router ospf 109
network (OSPF)
Use the router rip global configuration command to configure the Routing Information Protocol (RIP) routing process. Use the no form of this command to turn off the RIP routing process.
router ripThis command has no arguments or keywords.
No RIP routing process is defined.
Global configuration
The following example shows how to begin the RIP routing process:
router rip
network (RIP)
Use the set automatic-tag route-map configuration command to automatically compute the tag value. Use the no form of this command to disable this function.
set automatic-tagThis command has no arguments or keywords.
Disabled
Route-map configuration
You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all of a route map's match criteria are met. When all match criteria are met, all set actions are performed.
In the following example, the communication server is configured to automatically compute the tag value for the BGP learned routes:
route-map tag
match as path 10
set automatic-tag
!
router bgp 100
table-map tag
match
route-map
Use the set level route-map configuration command to indicate where to import routes. Use the no form of this command to delete the entry.
set level {level-1 | level-2 | level-1-2 | stub-area | backbone}| level-1 | Import into a Level-1 area |
| level-2 | Import into Level-2 sub-domain |
| level-1-2 | Import into Level-1 and Level-2 |
| stub-area | Import into OSPF NSSA area |
| backbone | Import into OSPF backbone area |
Disabled
For IS-IS destinations, the default value is level-2. For OSPF destinations, the default value is backbone.
Route-map configuration
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all of a route map's match criteria are met. When all match criteria are met, all set actions are performed.
In the following example, routes will be imported into the Level 1 area:
route-map name
set level level-l
match
route-map
Use the set local-preference route-map configuration command to specify a preference value for autonomous system path. Use the no form of this command to delete the entry.
set local-preference value| value | Preference value. An integer from 0 through 4294967295. |
Preference value of 100
Route-map configuration
The preference is sent only to all communication servers in the local autonomous system.
You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all of a route map's match criteria are met. When all match criteria are met, all set actions are performed.
You can change the default preference value with the bgp default local-preference command.
In the following example, the local preference of is set to 100 for all routes that are included in access list 1:
route-map map-preference
match as-path 1
set local-preference 100
match
route-map
Use the set metric route-map configuration command to set the metric value for the destination routing protocol. Use the no form of this command to return to the default metric value.
set metric metric-value| metric-value | Metric value or IGRP bandwidth in kilobits per second. An integer from 0 through 294967295. |
Default metric value.
Route-map configuration
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all of a route map's match criteria are met. When all match criteria are met, all set actions are performed.
In the following example, the metric value for the destination routing protocol is set to 100:
route-map set-metric
set metric 100
match
route-map
Use the set metric-type route-map command to set the metric type for the destination routing protocol. Use the no form of this command to disable the metric type for the destination routing protocol.
set metric-type {type-1 | type-2}| type-1 | OSPF external type 1 metric |
| type-2 | OSPF external type 2 metric |
Disabled
Route-map configuration
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all of a route map's match criteria are met. When all match criteria are met, all set actions are performed.
In the following example, the metric type of the destination protocol is set to OSPF external type 1:
route-map map-type
set metric-type type-1
match
route-map
Use the set next-hop route-map configuration command to specify the address of the next hop. Use the no form of this command to delete the entry.
set next-hop next-hop| next-hop | IP address of the next hop communication server |
Default next-hop address.
Route-map configuration
You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all of a route map's match criteria are met. When all match criteria are met, all set actions are performed.
In the following example, routes that pass the access list have the next hop set to 198.92.70.24:
route-map map_hop
match address 5
set next-hop 198.92.70.24
match
route-map
Use the set origin route-map configuration command to set the BGP origin code. Use the no form of this command to delete the entry.
set origin {igp | egp remote-as | incomplete}| igp | Remote EGP. |
| egp | Local IGP. |
| remote-as | Remote autonomous system. An integer from 0 through 65535. |
| incomplete | Unknown heritage. |
Default origin, based on route in main IP routing table.
Route-map configuration
You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all of a route map's match criteria are met. When all match criteria are met, all set actions are performed.
In the following example, routes that pass the route map have the origin set to IGP:
route-map set_origin
match as-path 10
set origin igp
match
route-map
Use the set tag route-map configuration command to set a tag value of the destination routing protocol. Use the no form of this command to delete the entry.
set tag tag-value| tag-value | Name for the tag. Integer from 0 through 4294967295. |
If not specified, the default action is to forward the tag in the source routing protocol onto the new destination protocol.
Route-map configuration
Use the route-map global configuration command, and the route-map configuration commands match and set, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria--the conditions under which redistribution is allowed for the current route-map. The set commands specify the set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all of a route map's match criteria are met. When all match criteria are met, all set actions are performed.
In the following example, the tag value of the destination routing protocol is set to 5:
route-map tag
set tag 5
match
route-map
Use the set weight route-map configuration command to specify the BGP weight for the routing table. Use the no form of this command to delete the entry.
set weight weight| weight | Weight value. From 0 through 65535. |
The weight will not be changed by the specified route map.
Route-map configuration
You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.
The implemented weight is based on the first matched autonomous system path. Weights indicated when an autonomous system path is matched override the weights assigned by global neighbor commands. In other words, the weights assigned with the match as-path and set weight route-map commands override the weights assigned using the neighbor weight and neighbor filter-list commands.
In the following example, the BGP weight for the routes matching the autonomous system path access list is set to 200:
route-map set-weight
match as-path 10
set weight 200
match
route-map
Use the show ip bgp EXEC command to display a particular network in the BGP routing table.
show ip bgp [network] [network-mask] [subnets]| network | (Optional) Network number, entered to display a particular network in the BGP routing table. |
| network-mask | (Optional) Displays all BGP routes matching the address/mask pair. |
| subnets | (Optional) Displays route and more specific routes. |
EXEC
The following is sample output from the show ip bgp command:
cs# show ip bgp
BGP table version is 716977, local communication server ID is 193.0.32.1
Status codes: s suppressed, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* i3.0.0.0 193.0.22.1 0 100 0 1800 1239 ?
*>i 193.0.16.1 0 100 0 1800 1239 ?
* i6.0.0.0 193.0.22.1 0 100 0 1800 690 568 ?
*>i 193.0.16.1 0 100 0 1800 690 568 ?
* i7.0.0.0 193.0.22.1 0 100 0 1800 701 35 ?
*>i 193.0.16.1 0 100 0 1800 701 35 ?
* 198.92.72.24 0 1878 704 701 35 ?
* i8.0.0.0 193.0.22.1 0 100 0 1800 690 560 ?
*>i 193.0.16.1 0 100 0 1800 690 560 ?
* 198.92.72.24 0 1878 704 701 560 ?
* i13.0.0.0 193.0.22.1 0 100 0 1800 690 200 ?
*>i 193.0.16.1 0 100 0 1800 690 200 ?
* 198.92.72.24 0 1878 704 701 200 ?
* i15.0.0.0 193.0.22.1 0 100 0 1800 174 ?
*>i 193.0.16.1 0 100 0 1800 174 ?
* i16.0.0.0 193.0.22.1 0 100 0 1800 701 i
*>i 193.0.16.1 0 100 0 1800 701 i
* 198.92.72.24 0 1878 704 701 i
Table 18-8 describes significant fields shown in the display.
| Field | Description |
|---|---|
| BGP table version is 716977 | Internal version number for the table. This is incremented any time the table changes. |
| local communication server ID | An Internet address of the communication server. |
| Status codes | Asterisk (*) indicates that the table entry is valid. A > character indicates that the table entry is the best entry to use for that network. A lowercase "i" indicates that the table entry was learned via an internal BGP session. A lowercase "s" indicates that the table entry is suppressed. |
| Network | Internet address of the network the entry describes. |
| Next Hop | IP address of the next system to use when forwarding a packet to the destination network. An entry of 0.0.0.0 indicates that the communication server has some non-BGP route to this network. |
| Metric | If shown, this is the value of the interautonomous system metric. This is frequently not used. |
| Weight | Set through the use of autonomous system filters. |
| Path | Autonomous system paths to the destination network. There can be one entry in this field for each autonomous system in the path. At the end of the path is the origin code for the path. A lowercase "i" indicates that the entry was originated with the IGP and advertised with a network router configuration command. A lowercase "e" indicates that the route originated with EGP. A question mark (?) indicates that the origin of the path is not clear. Usually this is a path that is redistributed into BGP from an IGP. |
| LocPrf | Local preference value. Default is 100. |
The following is sample output from the show ip bgp subnets command:
cs# show ip bgp 198.92.0.0 255.255.0.0 subnets
BGP table version is 1738, local communication server ID is 198.92.72.24
Status codes: s suppressed, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 198.92.0.0 198.92.72.30 8896 32768 ?
* 198.92.72.30 0 109 108 ?
*> 198.92.1.0 198.92.72.30 8796 32768 ?
* 198.92.72.30 0 109 108 ?
*> 198.92.11.0 198.92.72.30 42482 32768 ?
* 198.92.72.30 0 109 108 ?
*> 198.92.14.0 198.92.72.30 8796 32768 ?
* 198.92.72.30 0 109 108 ?
*> 198.92.15.0 198.92.72.30 8696 32768 ?
* 198.92.72.30 0 109 108 ?
*> 198.92.16.0 198.92.72.30 1400 32768 ?
* 198.92.72.30 0 109 108 ?
*> 198.92.17.0 198.92.72.30 1400 32768 ?
* 198.92.72.30 0 109 108 ?
*> 198.92.18.0 198.92.72.30 8876 32768 ?
* 198.92.72.30 0 109 108 ?
*> 198.92.19.0 198.92.72.30 8876 32768 ?
* 198.92.72.30 0 109 108 ?
Use the show ip bgp cidr-only privileged EXEC command to display only routes with non-natural network masks.
show ip bgp cidr-onlyThis command has no arguments or keywords.
Privileged EXEC
The following is sample output for the show ip bgp cidr-only command:
cs# show ip bgp cidr-only
BGP table version is 220, local communication server ID is 198.92.73.131
Status codes: s suppressed, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 192.0.0.0/8 198.92.72.24 0 1878 ?
*> 198.92.0.0/16 198.92.72.30 0 108 ?
Table 18-8 describes significant fields shown in the display.
| Field | Description |
|---|---|
| BGP table version is 220 | Internal version number for the table. This is incremented any time the table changes. |
| local communication server ID | An Internet address of the communication server. |
| Status codes | s The table entry is suppressed.
* The table entry is valid. > The table entry is the best entry to use for that network. i The table entry was learned via an internal BGP session. |
| Network | Internet address of the network the entry describes. |
| Next Hop | IP address of the next system to use when forwarding a packet to the destination network. An entry of 0.0.0.0 indicates that the communication server has some non-BGP route to this network. |
| LocPrf | Local preference value. Default is 100. |
| Metric | If shown, this is the value of the interautonomous system metric. This is frequently not used. |
| Weight | Set through the use of autonomous system filters. |
| Path | Autonomous system paths to the destination network. There can be one entry in this field for each autonomous system in the path. At the end of the path is the origin code for the path.
i The entry was originated with the IGP and advertised with a e The route originated with EGP. ? The origin of the path is not clear. Usually this is a path that is |
Use the show ip bgp filter-list privileged EXEC command to display routes that conform to a specified filter list.
show ip bgp filter-list access-list-number| access-list-number | Regular expression access list number from 1 through 199 |
Privileged EXEC
The following is sample output from the show ip bgp filter-list command:
cs# show ip bgp filter-list 2
BGP table version is 1738, local communication server ID is 198.92.72.24
Status codes: s suppressed, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* 198.92.0.0 198.92.72.30 0 109 108 ?
* 198.92.1.0 198.92.72.30 0 109 108 ?
* 198.92.11.0 198.92.72.30 0 109 108 ?
* 198.92.14.0 198.92.72.30 0 109 108 ?
* 198.92.15.0 198.92.72.30 0 109 108 ?
* 198.92.16.0 198.92.72.30 0 109 108 ?
* 198.92.17.0 198.92.72.30 0 109 108 ?
* 198.92.18.0 198.92.72.30 0 109 108 ?
* 198.92.19.0 198.92.72.30 0 109 108 ?
* 198.92.24.0 198.92.72.30 0 109 108 ?
* 198.92.29.0 198.92.72.30 0 109 108 ?
* 198.92.30.0 198.92.72.30 0 109 108 ?
* 198.92.33.0 198.92.72.30 0 109 108 ?
* 198.92.35.0 198.92.72.30 0 109 108 ?
* 198.92.36.0 198.92.72.30 0 109 108 ?
* 198.92.37.0 198.92.72.30 0 109 108 ?
* 198.92.38.0 198.92.72.30 0 109 108 ?
* 198.92.39.0 198.92.72.30 0 109 108 ?
Table 18-8 describes significant fields shown in the display.
| Field | Description |
|---|---|
| BGP table version is 1738 | Internal version number for the table. This is incremented any time the table changes. |
| local communication server ID | An Internet address of the communication server. |
| Status codes | s The table entry is suppressed.
* The table entry is valid. > The table entry is the best entry to use for that network. i The table entry was learned via an internal BGP session. |
| Network | Internet address of the network the entry describes. |
| Next Hop | IP address of the next system to use when forwarding a packet to the destination network. An entry of 0.0.0.0 indicates that the communication server has some non-BGP route to this network. |
| LocPrf | Local preference value. Default is 100. |
| Metric | If shown, this is the value of the interautonomous system metric. This is frequently not used. |
| Weight | Set through the use of autonomous system filters. |
| Path | Autonomous system paths to the destination network. There can be one entry in this field for each autonomous system in the path. At the end of the path is the origin code for the path.
i The entry was originated with the IGP and advertised with a e The route originated with EGP. ? The origin of the path is not clear. Usually this is a path that is |
Use the show ip bgp neighbors EXEC command to display detailed information on the TCP and BGP connections to individual neighbors.
show ip bgp neighbors [address] [routes | paths]| address | (Optional) Address of the neighbor whose routes you have learned from |
| routes | (Optional) Routes of specified neighbors |
| paths | (Optional) Autonomous system path of specified neighbor |
EXEC
The following is sample output from the show ip bgp neighbors command:
cs# show ip bgp neighbors
BGP neighbor is 131.108.6.68, remote AS 10, external link
BGP version 3, remote communication server ID 131.108.6.68
BGP state = Established, table version = 22, up for 0:00:13
Last read 0:00:12, hold time is 180, keepalive interval is 60 seconds
Received 24 messages, 0 notifications
Sent 28 messages, 4 notifications
Connections established 1; dropped 0
Connection state is ESTAB, I/O status: 1, unread input bytes: 0
Local host: 131.108.6.69, 12288 Foreign host: 131.108.6.68, 179
Enqueued packets for retransmit: 0, input: 0, saved: 0
Event Timers (current time is 835828):
Timer: Retrans TimeWait AckHold SendWnd KeepAlive
Starts: 20 0 18 0 0
Wakeups: 1 0 2 0 0
Next: 0 0 0 0 0
iss: 60876 snduna: 62649 sndnxt: 62649 sndwnd: 1872
irs: 95187024 rcvnxt: 95188733 rcvwnd: 1969 delrcvwnd: 271
SRTT: 364 ms, RTTO: 1691 ms, RTV: 481 ms, KRTT: 0 ms
minRTT: 4 ms, maxRTT: 340 ms, ACK hold: 300 ms
Flags: higher precedence
Datagrams (max data segment is 1450 bytes):
Rcvd: 36 (out of order: 0), with data: 18, total data bytes: 1708
Sent: 40 (retransmit: 1), with data: 36, total data bytes: 1817
Table 18-10 describes significant fields shown in the display.
| Field | Description |
|---|---|
| BGP neighbor | Lists the IP address of the BGP neighbor and its autonomous system number. If the neighbor is in the same autonomous system as the communication server, then the link between them is internal. Otherwise, it is considered external. |
| BGP version | Specifies that the BGP version being used to communicate with the remote communication server is BGP version 3; the neighbor's communication server ID (an IP address) is also specified. |
| BGP state | Indicates the internal state of this BGP connection. |
| table version | Indicates that the neighbor has been updated with this version of the primary BGP routing table. |
| up time | Indicates the amount of time that the underlying TCP connection has been in existence. |
| Last read | Time that BGP last read a message from this neighbor. |
| hold time | Maximum amount of time that can elapse between messages from the peer. |
| keepalive interval | Time period between sending keepalive packets, which help ensure that the TCP connection is up. |
| Received | Number of received messages indicates the number of total BGP messages received from this peer, including keepalives. The number of notifications is the number of error messages received from the peer. |
| Sent | The number of sent messages indicates the total number of BGP messages that have been sent to this peer, including keepalives. The number of notifications is the number of error messages that we have sent to this peer. |
| Connections established | The number of connections established is a count of the number of times that we have established a TCP connection and the two peers have agreed speak BGP with each other. The number of dropped connections is the number of times that a good connection has failed or been taken down. |
The remainder of the display describes the status of the underlying TCP connection.
The following is sample output from the show ip bgp neighbors paths command:
cs# show ip bgp neighbors 198.92.72.24 paths
Address Refcount Metric Path
0x3BAE7C 41 0 1878 ?
0x3BA714 3 0 1878 1755 i
0x3BA58C 1 0 1878 i
Table 18-12 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Address | Internal address where the path is stored. |
| Refcount | Number of routes using that path. |
| Metric | The MULTI_EXIT_DISC metric for the path. (The name of this metric for BGP versions 2 and 3 is INTER_AS.) |
| Path | The AS_PATH for that route, followed by the origin code for that route:
i The entry was originated with the IGP and advertised with a e The route originated with EGP. ? The origin of the path is not clear. Usually this is a path that is |
Use the show ip bgp paths EXEC command to display all the BGP paths in the database.
show ip bgp pathsThis command has no arguments or keywords.
EXEC
The following is sample output from the show ip bgp paths command:
cs# show ip bgp paths
Address Hash Refcount Metric Path
0x297A9C 0 2 0 i
0x30BF84 1 0 0 702 701 ?
0x2F7BC8 2 235 0 ?
0x2FA1D8 3 0 0 702 701 i
Table 18-12 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Address | Internal address where the path is stored. |
| Hash | Hash bucket where path is stored. |
| Refcount | Number of routes using that path. |
| Metric | The MULTI_EXIT_DISC metric for the path. (The name of this metric for BGP versions 2 and 3 is INTER_AS.) |
| Path | The AS_PATH for that route, followed by the origin code for that route. |
Use the show ip bgp regexp privileged EXEC command to display routes matching the regular expression.
show ip bgp regexp regular-expression| regular-expression | Regular expression to match the BGP autonomous system paths |
Privileged EXEC
cs# show ip bgp regexp 108$
BGP table version is 1738, local communication server ID is 198.92.72.24
Status codes: s suppressed, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* 198.92.0.0 198.92.72.30 0 109 108 ?
* 198.92.1.0 198.92.72.30 0 109 108 ?
* 198.92.11.0 198.92.72.30 0 109 108 ?
* 198.92.14.0 198.92.72.30 0 109 108 ?
* 198.92.15.0 198.92.72.30 0 109 108 ?
* 198.92.16.0 198.92.72.30 0 109 108 ?
* 198.92.17.0 198.92.72.30 0 109 108 ?
* 198.92.18.0 198.92.72.30 0 109 108 ?
* 198.92.19.0 198.92.72.30 0 109 108 ?
* 198.92.24.0 198.92.72.30 0 109 108 ?
* 198.92.29.0 198.92.72.30 0 109 108 ?
* 198.92.30.0 198.92.72.30 0 109 108 ?
* 198.92.33.0 198.92.72.30 0 109 108 ?
* 198.92.35.0 198.92.72.30 0 109 108 ?
* 198.92.36.0 198.92.72.30 0 109 108 ?
* 198.92.37.0 198.92.72.30 0 109 108 ?
* 198.92.38.0 198.92.72.30 0 109 108 ?
* 198.92.39.0 198.92.72.30 0 109 108 ?
Use the show ip bgp summary EXEC command to display the status of all BGP connections.
show ip bgp summaryThis command has no arguments or keywords.
EXEC
The following is sample output from the show ip bgp summary command:
cs# show ip bgp summary
BGP table version is 717029, main routing table version 717029
19073 network entries (37544 paths) using 3542756 bytes of memory
691 BGP path attribute entries using 57200 bytes of memory
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State
193.0.16.1 4 1755 32642 2973 717029 0 0 1:27:11
193.0.17.1 4 1755 4790 2973 717029 0 0 1:27:51
193.0.18.1 4 1755 7722 3024 717029 0 0 1:28:13
193.0.19.1 4 1755 0 0 0 0 0 2d02 Active
193.0.20.1 4 1755 3673 3049 717029 0 0 2:50:10
193.0.21.1 4 1755 3741 3048 717029 0 0 12:24:43
193.0.22.1 4 1755 33129 3051 717029 0 0 12:24:48
193.0.23.1 4 1755 0 0 0 0 0 2d02 Active
193.0.24.1 4 1755 0 0 0 0 0 2d02 Active
193.0.25.1 4 1755 0 0 0 0 0 2d02 Active
193.0.26.1 4 1755 0 0 0 0 0 2d02 Active
193.0.27.1 4 1755 4269 3049 717029 0 0 12:39:33
193.0.28.1 4 1755 3037 3050 717029 0 0 2:08:15
198.92.72.24 4 1878 11635 13300 717028 0 0 0:50:39
Table 18-13 describes significant fields shown in the display.
| Field | Description |
|---|---|
| BGP table version | Internal version number of BGP database. |
| main routing table version | Indicates last version of BGP database that was injected into main routing table. |
| Neighbor | IP address of a neighbor. |
| V | Indicates BGP version number spoken to that neighbor. |
| MsgRcvd | BGP messages received from that neighbor. |
| MsgSent | BGP messages sent to that neighbor. |
| TblVer | Last version of the BGP database that was sent to that neighbor. |
| InQ | Number of messages from that neighbor waiting to be processed. |
| OutQ | Number of messages waiting to be sent to that neighbor. |
| Update/State | The length of time that the BGP session has been in state Established, or the current state if it is not Established. |
To display the contents of the DVMRP routing table, use the show ip dvmrp route EXEC command.
show ip dvmrp route [ip-address]| ip-address | (Optional) IP address of an entry in the DVMRP routing table. |
EXEC
The following is sample output of the show ip dvmrp route command:
DVMRP Routing Table - 3 entries
13.0.32.0/22 [0/11]
via 192.88.195.10, Tunnel1, uptime 3:50:24, expires 0:02:24
13.0.52.0/22 [0/9]
via 192.88.195.10, Tunnel1, uptime 0:59:14, expires 0:02:24
13.1.68.0/22 [0/8]
via 192.88.195.10, Tunnel1, uptime 3:50:24, expires 0:02:24
Table 18-14 describes the fields shown in the display
| Field | Description |
|---|---|
| 3 entries | Number of entries in the DMVRP routing table. |
| 13.0.32.0/22 | Source network. |
| [0/11] | Administrative distance/reliability. |
| via 192.88.195.10 | Next-hop communication server to the source network. |
| Tunnel1 | Interface to the source network. |
| uptime | How long in hours, minutes, and seconds that the route has been in the DVMRP routing table. |
| expires | How long in hours, minutes, and seconds until the entry is removed from the DVMRP routing table. |
ip dvmrp accept-filter
Use the show ip egp EXEC command to display statistics on EGP connections and neighbors.
show ip egpThis command has no arguments or keywords.
EXEC
The following is sample output from the show ip egp command:
cs# show ip egp
Local autonomous system is 109
EGP Neighbor FAS/LAS State SndSeq RcvSeq Hello Poll j/k Flags
10.3.0.27 1/109 IDLE 625 61323 60 180 0 Perm, Act
* 10.2.0.37 1/109 UP 12:29 250 14992 60 180 3 Perm, Act
* 10.7.0.63 1/109 UP 1d19 876 10188 60 180 4 Perm, Pass
Table 18-15 describes the fields shown in the display.
| Field | Description |
|---|---|
| EGP Neighbor | Address of the EGP neighbor. |
| FAS | Foreign autonomous system number. |
| LAS | Local autonomous system number. |
| State | State of the connection between peers. |
| SndSeq | Send sequence number. |
| RcvSeq | Receive sequence number. |
| Hello | Interval between Hello/I-Heard-You packets. |
| Poll | Interval between Poll/Update packets. |
| j/k | Measure of reachability; 4 is perfect. |
| Flags | Perm--Permanent.
Temp--Temporary (neighbor will be removed). Act--Active, controlling the connection. Pass--Passive, neighbor controls the connection. |
To display the neighbors discovered by IP Enhanced IGRP, use the show ip eigrp neighbors EXEC command.
show ip eigrp neighbors [type number]| type | (Optional) Interface type |
| number | (Optional) Interface number |
EXEC
Use the show ip eigrp neighbors command to determine when neighbors become active and inactive. It is also useful for debugging certain types of transport problems.
The following is sample output from the show ip eigrp neighbors command:
cs# show ip eigrp neighbors
IP-EIGRP Neighbors for process 77
Address Interface Holdtime Uptime Q Seq SRTT RTO
(secs) (h:m:s) Count Num (ms) (ms)
160.89.81.28 Ethernet1 13 0:00:41 0 11 4 20
160.89.80.28 Ethernet0 14 0:02:01 0 10 12 24
160.89.80.31 Ethernet0 12 0:02:02 0 4 5 20
Table 18-16 explains the fields in the output.
| Field | Description |
|---|---|
| process 77 | Autonomous system number specified in the ipx router configuration command. |
| Address | IP address of the Enhanced IGRP peer. |
| Interface | Interface on which the communication server is receiving hello packets from the peer. |
| Holdtime | Length of time, in seconds, that the communication server will wait to hear from the peer before declaring it down. If the peer is using the default hold time, this number will be less than 15. If the peer configures a nondefault hold time, it will be reflected here. |
| Uptime | Elapsed time, in hours, minutes, and seconds, since the local communication server first heard from this neighbor. |
| Q Count | Number of IP Enhanced IGRP packets (Update, Query, and Reply) that the communication server is waiting to send. |
| Seq Num | Sequence number of the last update, query, or reply packet that was received from this neighbor. |
| SRTT | Smooth round-trip time. This is the number of milliseconds it takes for an IP Enhanced IGRP packet to be sent to this neighbor and for the local communication server to receive an acknowledgment of that packet. |
| RTO | Retransmission timeout, in milliseconds. This is the amount of time the communication server waits before retransmitting a packet from the retransmission queue to a neighbor. |
To display the IP Enhanced IGRP topology table, use the show ip eigrp topology EXEC command.
show ip eigrp topology [autonomous-system-number | [[ip-address] mask]]| autonomous-system-number | (Optional) A decimal number between 1 and 65535. |
| ip-address | (Optional) When specified with a mask, a detailed description of the entry is provided. |
| mask | (Optional) Subnet mask. |
EXEC
Use the show ip eigrp topology command to determine DUAL states and to debug possible DUAL problems.
The following is sample output from the show ip eigrp topology command:
cs# show ip eigrp topology
IP-EIGRP Topology Table for process 77
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - Reply status
P 160.89.90.0 255.255.255.0, 2 successors, FD is 0
via 160.89.80.28 (46251776/46226176), Ethernet0
via 160.89.81.28 (46251776/46226176), Ethernet1
via 160.89.80.31 (46277376/46251776), Ethernet0
P 160.89.81.0 255.255.255.0, 1 successors, FD is 307200
via Connected, Ethernet1
via 160.89.81.28 (307200/281600), Ethernet1
via 160.89.80.28 (307200/281600), Ethernet0
via 160.89.80.31 (332800/307200), Ethernet0
Table 18-17 explains the fields in the output.
| Field | Description |
|---|---|
| Codes | State of this topology table entry. Passive and Active refer to the Enhanced IGRP state with respect to this destination; Update, Query, and Reply refer to the type of packet that is being sent. |
| P - Passive | No Enhanced IGRP computations are being performed for this destination. |
| A - Active | Enhanced IGRP computations are being performed for this destination. |
| U - Update | Indicates that an update packet was sent to this destination. |
| Q - Query | Indicates that a query packet was sent to this destination. |
| R - Reply | Indicates that a reply packet was sent to this destination. |
| r - Reply status | Flag that is set when after the communication server has sent a query and is waiting for a reply. |
| 160.89.90.0 and so on | Destination IP network number. |
| 255.255.255.0 | Destination subnet mask. |
| successors | Number of successors. This number corresponds to the number of next hops in the IP routing table. |
| FD | Feasible distance. This value is used in the feasibility condition check. If the neighbor's reported distance (the metric after the slash) is less than the feasible distance, the feasibility condition is met and that path is a feasible successor. Once the communication server determines it has a feasible successor, it does not have to send a query for that destination. |
| replies | Number of replies that are still outstanding (have not been received) with respect to this destination. This information appears only when the destination is in Active state. |
| state | Exact Enhanced IGRP state that this destination is in. It can be the number 0, 1, 2, or 3. This information appears only when the destination is Active. |
| via | IP address of the peer who told the communication server about this destination. The first N of these entries, where N is the number of successors, are the current successors. The remaining entries on the list are feasible successors. |
| (46251776/46226176) | The first number is the Enhanced IGRP metric that represents the cost to the destination. The second number is the Enhanced IGRP metric that this peer advertised. |
| Ethernet0 | Interface from which this information was learned. |
To display the number of IP Enhanced IGRP packets sent and received, use the show ip eigrp traffic EXEC command.
show ip eigrp traffic [autonomous-system-number]| autonomous-system-number | (Optional) A decimal number between 1 and 65535. |
EXEC
The following is sample output from the show ip eigrp traffic command:
cs# show ip eigrp traffic
IP-EIGRP Traffic Statistics for process 77
Hellos sent/received: 218/205
Updates sent/received: 7/23
Queries sent/received: 2/0
Replies sent/received: 0/2
Acks sent/received: 21/14
Table 18-18 describes the fields that might be shown in the display.
| Field | Description |
|---|---|
| process 77 | Autonomous system number specified in the ip router command. |
| Hellos sent/received | Number of hello packets that were sent and received. |
| Updates sent/received | Number of update packets that were sent and received. |
| Queries sent/received | Number of query packets that were sent and received. |
| Replies sent/received | Number of reply packets that were sent and received. |
| Acks sent/received | Number of acknowledgment packets that were sent and received. |
To display the multicast groups that are directly connected to the communication server and that were learned via IGMP, use the show ip igmp groups EXEC command.
show ip igmp groups [group-name | group-address | type number]| group-name | (Optional) Name of the multicast group, as defined in the DNS hosts table. |
| group-address | (Optional) Address of the multicast group. This is a multicast IP address in four-part dotted notation. |
| type | (Optional) Interface type. |
| number | (Optional) Interface number. |
EXEC
If you omit all optional arguments, the show ip igmp groups command displays by group address and interface type and number all directly connected multicast groups.
The following is sample output of the show ip igmp groups command:
cs> show ip igmp groups
IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter
224.0.255.1 Ethernet0 18:51:41 0:02:15 198.92.37.192
224.2.226.60 Ethernet0 1:51:31 0:02:17 198.92.37.192
224.2.127.255 Ethernet0 18:51:45 0:02:17 198.92.37.192
226.2.2.2 Ethernet1 18:51:47 never 0.0.0.0
224.2.0.1 Ethernet0 18:51:43 0:02:14 198.92.37.192
225.2.2.2 Ethernet0 18:51:43 0:02:21 198.92.37.33
225.2.2.2 Ethernet1 18:51:47 never 0.0.0.0
225.2.2.4 Ethernet0 18:18:02 0:02:20 198.92.37.192
225.2.2.4 Ethernet1 18:23:32 0:02:55 198.92.36.128
Table 18-19 describes the fields shown in the display.
| Field | Description |
|---|---|
| Group address | Address of the multicast group. |
| Interface | Interface through which the group is reachable. |
| Uptime | How long in hours, minutes, and seconds this multicast group has been known. |
| Expires | How long in hours, minutes, and seconds until the entry is removed from the IGMP groups table. |
| Last Reporter | Last host to report being a member of the multicast group. |
ip igmp query-interval
To display multicast-related information about an interface, use the show ip igmp interface EXEC command.
show ip igmp interface [type number]| type | (Optional) Interface type. |
| number | (Optional) Interface number. |
EXEC
If you omit the optional arguments, the show ip igmp interface command displays information about all interfaces.
This command also displays information about dynamically learned DVMRP communication servers on the interface.
The following is sample output from the show ip igmp interface command:
cs> show ip igmp interface
Ethernet0 is up, line protocol is up
Internet address is 198.92.37.6, subnet mask is 255.255.255.0
IGMP is enabled on interface
IGMP query interval is 60 seconds
Inbound IGMP access group is not set
Multicast routing is enabled on interface
Multicast TTL threshold is 0
Multicast designated router (DR) is 198.92.37.33
No multicast groups joined
Ethernet1 is up, line protocol is up
Internet address is 198.92.36.129, subnet mask is 255.255.255.0
IGMP is enabled on interface
IGMP query interval is 60 seconds
Inbound IGMP access group is not set
Multicast routing is enabled on interface
Multicast TTL threshold is 0
Multicast designated router (DR) is 198.92.36.131
Multicast groups joined: 225.2.2.2 226.2.2.2
Tunnel0 is up, line protocol is up
Internet address is 10.1.37.2, subnet mask is 255.255.0.0
IGMP is enabled on interface
IGMP query interval is 60 seconds
Inbound IGMP access group is not set
Multicast routing is enabled on interface
Multicast TTL threshold is 0
No multicast groups joined
Table 18-20 describes the fields shown in the display.
| Field | Description |
|---|---|
| Ethernet0 is up, line protocol is up | Interface type, number, and status. |
| Internet address is... subnet mask is... | Internet address of the interface and subnet mask being applied to the interface, as specified with the ip address interface configuration command. |
| IGMP is enabled on interface | Indicates whether IGMP has been enabled on the interface with the ip pim interface configuration command. |
| IGMP query interval is 60 seconds | Interval at which the communication server sends PIM router-query messages, as specified with the ip igmp query-interval interface configuration command. |
| Inbound IGMP access group is not set | Indicates whether an IGMP access group has been configured with the ip igmp access-group interface configuration command. |
| Multicast routing is enabled on interface | Indicates whether multicast routing has been enabled on the interface with the ip pim interface configuration command. |
| Multicast TTL threshold is 0 | Packet time-to-threshold, as specified with the ip multicast-threshold interface configuration command. |
| Multicast designated router (DR) is ... | IP address of the designated router in the autonomous system. |
| Multicast groups joined: No multicast groups joined | Indicates whether this interface is a member of any multicast groups and, if so, lists the IP addresses of the groups. |
ip address
ip igmp access-group
ip igmp query-interval
ip multicast-threshold
ip pim
Use the show ip irdp EXEC command to display IRDP values.
show ip irdpThis command has no arguments or keywords.
EXEC
The following is sample output from the show ip irdp command:
cs# show ip irdp
Ethernet 0 has communication server discovery enabled
Advertisements will occur between every 450 and 600 seconds.
Advertisements are valid for 1800 seconds.
Default preference will be 100.
--More--
Serial 0 has communication server discovery disabled
--More--
Ethernet 1 has communication server discovery disabled
As the display shows, show ip irdp output indicates whether or not communication server discovery has been configured for each communication server interface, and lists the values of communication server discovery configurables for those interfaces on which communication server discovery has been enabled. Explanations for the less self-evident lines of output in the display follow.
Advertisements will occur between every 450 and 600 seconds.
Indicates the configured minimum and maximum advertising interval for the interface.
Advertisements are valid for 1800 seconds.
Indicates the configured holdtime values for the interface.
Default preference will be 100.
Indicates the configured (or in this case default) preference value for the interface.
To display the contents of the IP multicast routing table, use the show ip mroute EXEC command.
show ip mroute [group-name | group-address] [summary] [count]| group-name | (Optional) Name of the multicast group, as defined in the DNS hosts table. |
| group-address | (Optional) Address of the multicast group. This is a multicast IP address in four-part dotted notation. |
| summary | (Optional) Displays a one-line, abbreviated summary of each entry in the IP multicast routing table. |
| count | (Optional) Displays statistics about the group, source communication server, and multicast packets. |
| source-address | (Optional) Address of a communication server that is a member of the multicast group. |
EXEC
If you omit all optional arguments and keywords, the show ip mroute command displays all entries in the IP multicast routing table.
The communication server populates the multicast routing table by creating source, group (S,G) entries from star, group (*,G) entries. The star refers to all source addresses, the "S" refers to a single source address, and the "G" is the destination multicast group address. In creating (S,G) entries, the communication server uses the best path to that destination group found in the unicast routing table (that is, via Reverse Path Forwarding {RPF]).
The following is sample output from the show ip mroute command for a system operating is dense mode. This command displays the contents of the IP multicast routing table for the multicast group named cbone-audio.
cs> show ip mroute cbone-audio
IP Multicast Routing Table
Flags: P - Prune, D - Dense, S - Sparse, C - Connected, L - Local
(*, 224.0.255.1), uptime 0:57:31, expires 0:02:59, RP is 0.0.0.0, flags: DC
Incoming interface: Null, RPF neighbor 0.0.0.0
Outgoing interface list:
Ethernet0, Forward state, Dense mode, uptime 0:57:31, expires 0:02:52
Tunnel0, Forward state, Dense mode, uptime 0:56:55, expires 0:01:28
(198.92.37.100/32, 224.0.255.1), uptime 20:20:00, expires 0:02:55, flags: C
Incoming interface: Tunnel0, RPF neighbor 10.20.37.33
Outgoing interface list:
Ethernet0, Forward state, Dense mode, uptime 20:20:00, expires 0:02:52
The following is sample output from the show ip mroute command for a system operating in sparse mode:
cs# show ip mroute
IP Multicast Routing Table
Flags: P - Prune, D - Dense, S - Sparse, C - Connected, L - Local
(*, 224.0.255.3), uptime 5:29:15, RP is 198.92.37.2, flags: SC
Incoming interface: Tunnel0, RPF neighbor 10.3.35.1
Outgoing interface list:
Ethernet0, Forward state, Sparse mode, uptime 5:29:15, expires 0:02:57
(198.92.46.0/24, 224.0.255.3), uptime 5:29:15, expires 0:02:59, flags: C
Incoming interface: Tunnel0, RPF neighbor 10.3.35.1
Outgoing interface list:
Ethernet0, Forward state, Sparse mode, uptime 5:29:15, expires 0:02:57
Table 18-21 explains the fields shown in the displays.
| Field | Description |
|---|---|
| Flags: | Provides information about the entry. |
| P - Prune | Route has been pruned. The communication server keeps this information in case a downstream member wants to join the source. |
| D - Dense | Entry is operating in dense mode. |
| S - Sparse | Entry is operating in sparse mode. |
| C - Connected | A member of the multicast group is present on the directly connected interface. |
| L - Local | The communication server itself is a member of the multicast group. |
| (*, 224.0.255.1) (198.92.37.100/32, 224.0.255.1) | Entry in the IP multicast routing table. The entry consists of the IP address of the source communication server followed by IP address of the multicast group. An asterisk (*) in place of the source communication server indicates all sources.
Entries in the first format are referred to as (*,G,) or "star comma G," entries. Entries in the second format are referred to as (S,G) or ("S comma G") entries. (*,G) entries are used to build (S,G) entries. |
| uptime | How long in hours, minutes, and seconds the entry has been in the IP multicast routing table. |
| expires | How long in hours, minutes, and seconds until the entry will be removed from the IP multicast routing table on the outgoing interface. |
| RP | Address of the rendezvous point (RP) communication server. For communication servers operating in sparse mode, this address is always 0.0.0.0. |
| flags: | Information about the entry. |
| Incoming interface: | Expected interface for a multicast packet from the source. If the packet is not received on this interface, it is discarded. |
| RPF neighbor | IP address of the upstream communication server to the source. |
| Outgoing interface list: | Interfaces through which packets will be forwarded. |
| Ethernet0 | Name and number of the outgoing interface. |
| Forward state | Indicates that packets will be forwarded on the interface if there are no restrictions due to access lists or TTL threshold. |
| Dense mode Sparse mode | Mode in which the interface is operating. |
| Uptime | How long in hours, minutes, and seconds the entry has been in the IP multicast routing table. |
| Expires | How long in hours, minutes, and seconds until the entry will be removed from the IP multicast routing table. |
ip igmp query-interval
Use the show ip ospf EXEC command to display general information about OSPF routing processes in a particular communication server.
show ip ospf [process-id]| process-id | (Optional) Specifies a process ID. If this argument is included, only information for the specified routing process is included. |
EXEC
The following is sample output from the show ip ospf command when entered without a specific OSPF process ID:
cs# show ip ospf
Routing Process "ospf 201" with ID 192.42.110.200
Supports only single TOS(TOS0) route
It is an area border and autonomous system boundary router
Summary Link update interval is 0:30:00 and the update due in 0:16:26
External Link update interval is 0:30:00 and the update due in 0:16:27
Redistributing External Routes from,
igrp 200 with metric mapped to 2, includes subnets in redistribution
rip with metric mapped to 2
igrp 2 with metric mapped to 100
igrp 32 with metric mapped to 1
Number of areas in this communication server is 3
Area 192.42.110.0
Number of interfaces in this area is 1
Area has simple password authentication
SPF algorithm executed 6 times
Area ranges are
Link State Update Interval is 0:30:00 and due in 0:16:55
Link State Age Interval is 0:20:00 and due in 0:06:55
Table 18-22 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Routing process "ospf 201" with ID 192.42.110.200 | Process ID and OSPF communication server ID. |
| Type of Service | Number of Types of Service supported (Type 0 only). |
| Type of OSPF Router | Possible types are internal, area border, or autonomous system boundary. |
| Summary Link update interval | Specify summary update interval in hours:minutes:seconds, and time to next update. |
| External Link update interval | Specify external update interval in hours:minutes:seconds, and time to next update. |
| Redistributing External Routes from | Lists of redistributed routes, by protocol. |
| Number of areas | Number of areas in the communication server, area addresses, and so on. |
| Link State Update Interval | Specify communication server and network link state update interval in hours:minutes:seconds, and time to next update. |
| Link State Age Interval | Specify max-aged update deletion interval and time until next database cleanup in hours:minutes:seconds. |
Use the show ip ospf border-routers privileged EXEC command to display the internal OSPF routing table entries to a communication server acting as an Area Border Router (ABR) or Autonomous System Boundary Router (ASBR).
show ip ospf borders-routersThis command has no arguments or keywords.
Privileged EXEC
The following is sample output from the show ip ospf border-routers command:
cs# show ip ospf border-routers
OSPF Process 109 internal Routing Table
Destination Next Hop Cost Type Rte Type Area SPF No
160.89.97.53 144.144.1.53 10 ABR INTRA 0.0.0.3 3
160.89.103.51 160.89.96.51 10 ABR INTRA 0.0.0.3 3
160.89.103.52 160.89.96.51 20 ASBR INTER 0.0.0.3 3
160.89.103.52 144.144.1.53 22 ASBR INTER 0.0.0.3 3
Table 18-23 describes the fields shown in the display.
| Field | Description |
|---|---|
| Destination | Destination communication server ID. |
| Next Hop | Next hop toward the destination. |
| Cost | Cost of using this route. |
| Type | The communication server type of the destination; it is either an Area Border Router (ABR) or Autonomous System Boundary Router (ASBR) or both. |
| Rte Type | The type of this route, it is either an intra-area or interarea route. |
| Area | The area ID of the area that this route is learned from. |
| SPF No | The internal number of SPF calculation that installs this route. |
Use the show ip ospf database EXEC command to display lists of information related to the OSPF database for a specific communication server. The various forms of this command deliver information about different OSPF link state advertisements.
show ip ospf [process-id area-id] databaseEXEC
| process-id
| (Optional) Internally used identification parameter. It is locally assigned and can be any positive integer number. The number used here is the number assigned administratively when enabling the OSPF routing process. |
| area-id
| (Optional) Area number associated with the OSPF address range defined in the network router configuration command used to define the particular area. |
| link-state-id
| (Optional) Identifies the portion of the Internet environment that is being described by the advertisement. The value entered depends on the advertisement's LS type. It must be entered in the form of an IP address.
When the link state advertisement is describing a network, the link-state-id can take one of two forms: --The network's IP address (as in type 3 summary link advertisements and in autonomous system external link advertisements). --A derived address obtained from the link state ID. (Note that masking a network links advertisement's link state ID with the network's subnet mask yields the network's IP address.) When the link state advertisement is describing a communication server, the link state ID is always the described communication server's OSPF communication server ID. When an autonomous system external advertisement (LS Type = 5) is describing a default route, its link state ID is set to Default Destination (0.0.0.0). |
When entered with the optional keywords router, network, summary, asb-summary, and external, different displays result. Examples and brief descriptions of each form follow.
The following is sample output from the show ip ospf database command when no optional arguments or keywords are used:
cs# show ip ospf database
OSPF Router with id(190.20.239.66) (Autonomous system 300)
Displaying Router Link States(Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum Link count
155.187.21.6 155.187.21.6 1731 0x80002CFB 0x69BC 8
155.187.21.5 155.187.21.5 1112 0x800009D2 0xA2B8 5
155.187.1.2 155.187.1.2 1662 0x80000A98 0x4CB6 9
155.187.1.1 155.187.1.1 1115 0x800009B6 0x5F2C 1
155.187.1.5 155.187.1.5 1691 0x80002BC 0x2A1A 5
155.187.65.6 155.187.65.6 1395 0x80001947 0xEEE1 4
155.187.241.5 155.187.241.5 1161 0x8000007C 0x7C70 1
155.187.27.6 155.187.27.6 1723 0x80000548 0x8641 4
155.187.70.6 155.187.70.6 1485 0x80000B97 0xEB84 6
Displaying Net Link States(Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
155.187.1.3 192.20.239.66 1245 0x800000EC 0x82E
Displaying Summary Net Link States(Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
155.187.240.0 155.187.241.5 1152 0x80000077 0x7A05
155.187.241.0 155.187.241.5 1152 0x80000070 0xAEB7
155.187.244.0 155.187.241.5 1152 0x80000071 0x95CB
Table 18-24 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Link ID | Communication server ID number. |
| ADV Router | Advertising communication server's ID. |
| Age | Link state age. |
| Seq# | Link state sequence number (detects old or duplicate link state advertisements). |
| Checksum | Fletcher checksum of the complete contents of the link state advertisement. |
| Link count | Number of interfaces detected for communication server. |
The following is sample output from the show ip ospf database communication server command when no optional arguments are specified:
cs# show ip ospf database router
OSPF Router with id(190.20.239.66) (Autonomous system 300)
Displaying Router Link States(Area 0.0.0.0)
LS age: 1176
Options: (No TOS-capability)
LS Type: Router Links
Link State ID: 155.187.21.6
Advertising Router: 155.187.21.6
LS Seq Number: 80002CF6
Checksum: 0x73B7
Length: 120
AS Boundary Router
155 Number of Links: 8
Link connected to: another Router (point-to-point)
(link ID) Neighboring Router ID: 155.187.21.5
(Link Data) Router Interface address: 155.187.21.6
Number of TOS metrics: 0
TOS 0 Metrics: 2
Table 18-25 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Router ID | Communication server ID number. |
| Autonomous system | OSPF autonomous system number (OSPF process ID). |
| LS age | Link state age. |
| Options | Type of Service options (Type 0 only). |
| LS Type | Link state type. |
| Link State ID | Link state ID. |
| Advertising Router | Advertising communication server's ID. |
| LS Seq Number | Link state sequence (detects old or duplicate link state advertisements). |
| Checksum | LS checksum (Fletcher checksum of the complete contents of the link state advertisement). |
| Length | Length in bytes of the link state advertisement. |
| AS Boundary Router | Definition of communication server type. |
| Number of Links | Number of active links. |
| link ID | Link type. |
| Link Data | Communication server interface address. |
| TOS | Type of Service metric (Type 0 only). |
The following is sample output from the show ip ospf database network command when no optional arguments are specified:
cs# show ip ospf database network
OSPF Router with id(190.20.239.66) (Autonomous system 300)
Displaying Net Link States(Area 0.0.0.0)
LS age: 1367
Options: (No TOS-capability)
LS Type: Network Links
Link State ID: 155.187.1.3 (address of Designated Router)
Advertising Router: 190.20.239.66
LS Seq Number: 800000E7
Checksum: 0x1229
Length: 52
Network Mask: 255.255.255.0
Attached Router: 190.20.239.66
Attached Router: 155.187.241.5
Attached Router: 155.187.1.1
Attached Router: 155.187.54.5
Attached Router: 155.187.1.5
Table 18-26 describes significant fields shown in the display.
| Field | Description |
|---|---|
| OSPF Router with ID(190.20.239.66) | Communication server ID number. |
| Autonomous system 300 | OSPF autonomous system number (OSPF process ID). |
| LS age: 1367 | Link state age. |
| Options: (No TOS-capability) | Type of Service options (Type 0 only). |
| LS Type: Network Links | Link state type. |
| Link State ID | Link state ID of designated communication server. |
| Advertising Router | Advertising communication server's ID. |
| LS Seq Number | Link state sequence (detects old or duplicate link state advertisements). |
| Checksum | LS checksum (Fletcher checksum of the complete contents of the link state advertisement). |
| Network Mask | Network mask implemented. |
| AS Boundary Router | Definition of communication server type. |
| Other fields | List of communication servers attached to the network, by IP address. |
The following is sample output from the show ip ospf database summary command when no optional arguments are specified:
cs# show ip ospf database summary
OSPF Router with id(190.20.239.66) (Autonomous system 300)
Displaying Summary Net Link States(Area 0.0.0.0)
LS age: 1401
Options: (No TOS-capability)
LS Type: Summary Links(Network)
Link State ID: 155.187.240.0 (summary Network Number)
Advertising Router: 155.187.241.5
LS Seq Number: 80000072
Checksum: 0x84FF
Length: 28
Network Mask: 255.255.255.0 TOS: 0 Metric: 1
Table 18-27 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Router ID | Communication server ID number. |
| Autonomous system | OSPF autonomous system number (OSPF process ID). |
| LS age | Link state age. |
| Options | Type of Service options (Type 0 only). |
| LS Type | Link state type. |
| Link State ID | Link state ID (summary network number). |
| Advertising Router | Advertising communication server's ID. |
| LS Seq Number | Link state sequence (detects old or duplicate link state advertisements). |
| Checksum | LS checksum (Fletcher checksum of the complete contents of the link state advertisement). |
| Length | Length in bytes of the link state advertisement. |
| Network Mask | Network mask implemented. |
| TOS | Type of Service. |
| Metric | Link state metric. |
The following is sample output from the show ip ospf database asb-summary command when no optional arguments are specified:
cs# show ip ospf database asb-summary
OSPF Router with id(190.20.239.66) (Autonomous system 300)
Displaying Summary ASB Link States(Area 0.0.0.0)
LS age: 1463
Options: (No TOS-capability)
LS Type: Summary Links(AS Boundary Router)
Link State ID: 155.187.245.1 (AS Boundary Router address)
Advertising Router: 155.187.241.5
LS Seq Number: 80000072
Checksum: 0x3548
Length: 28
Network Mask: 0.0.0.0 TOS: 0 Metric: 1
Table 18-28 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Router ID | Communication server ID number. |
| Autonomous system | OSPF autonomous system number (OSPF process ID). |
| LS age | Link state age. |
| Options | Type of Service options (Type 0 only). |
| LS Type | Link state type. |
| Link State ID | Link state ID (autonomous system boundary communication server). |
| Advertising Router | Advertising communication server's ID. |
| LS Seq Number | Link state sequence (detects old or duplicate link state advertisements). |
| Checksum | LS checksum (Fletcher checksum of the complete contents of the link state advertisement). |
| Length | Length in bytes of the link state advertisement. |
| Network Mask | Network mask implemented. |
| TOS | Type of Service. |
| Metric | Link state metric. |
The following is sample output from the show ip ospf database external command when no optional arguments are specified:
cs# show ip ospf database external
OSPF Router with id(190.20.239.66) (Autonomous system 300)
Displaying AS External Link States
LS age: 280
Options: (No TOS-capability)
LS Type: AS External Link
Link State ID: 143.105.0.0 (External Network Number)
Advertising Router: 155.187.70.6
LS Seq Number: 80000AFD
Checksum: 0xC3A
Length: 36
Network Mask: 255.255.0.0
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 1
Forward Address: 0.0.0.0
External Route Tag: 0
Table 18-29 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Router ID | Communication server ID number. |
| Autonomous system | OSPF autonomous system number (OSPF process ID). |
| LS age | Link state age. |
| Options | Type of Service options (Type 0 only). |
| LS Type | Link state type. |
| Link State ID | Link state ID (External Network Number). |
| Advertising Router | Advertising communication server's ID. |
| LS Seq Number | Link state sequence number (detects old or duplicate link state advertisements). |
| Checksum | LS checksum (Fletcher checksum of the complete contents of the link state advertisement). |
| Length | Length in bytes of the link state advertisement. |
| Network Mask | Network mask implemented. |
| Metric Type | External Type. |
| TOS | Type of Service. |
| Metric | Link state metric. |
| Forward Address | Forwarding address. Data traffic for the advertised destination will be forwarded to this address. If the forwarding address is set to 0.0.0.0, data traffic will be forwarded instead to the advertisement's originator. |
| External Route Tag | External route tag, a 32-bit field attached to each external route. This is not used by the OSPF protocol itself. |
Use the show ip ospf interface EXEC command to display OSPF-related interface information.
show ip ospf interface [type number]| type | (Optional) Interface type |
| number | (Optional) Interface number |
EXEC
The following is sample output from the show ip ospf interface command when Ethernet 0 is specified:
cs# show ip ospf interface ethernet 0
Ethernet 0 is up, line protocol is up
Internet Address 131.119.254.202, Mask 255.255.255.0, Area 0.0.0.0
AS 201, Router ID 192.77.99.1, Network Type BROADCAST, Cost: 10
Transmit Delay is 1 sec, State OTHER, Priority 1
Designated Router id 131.119.254.10, Interface address 131.119.254.10
Backup Designated communication server id 131.119.254.28, Interface addr 131.119.254.28
Timer intervals configured, Hello 10, Dead 60, Wait 40, Retransmit 5
Hello due in 0:00:05
Neighbor Count is 8, Adjacent neighbor count is 2
Adjacent with neighbor 131.119.254.28 (Backup Designated Router)
Adjacent with neighbor 131.119.254.10 (Designated Router)
Table 18-30 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Ethernet | Status of physical link and operational status of protocol. |
| Internet Address | Interface IP address, subnet mask, and area address. |
| AS | Autonomous system number (OSPF process ID), communication server ID, network type, link state cost. |
| Transmit Delay | Transmit delay, interface state, and communication server priority. |
| Designated Router | Designated communication server ID and respective interface IP address. |
| Backup Designated router | Backup designated communication server ID and respective interface IP address. |
| Timer intervals configured | Configuration of timer intervals. |
| Hello | Number of seconds until next Hello packet is sent out this interface. |
| Neighbor Count | Count of network neighbors and list of adjacent neighbors. |
Use the show ip ospf neighbor EXEC command to display OSPF-neighbor information on a per-interface basis.
show ip ospf neighbor [type number] [neighbor-id] detail| type | (Optional) Interface type |
| number | (Optional) Interface number |
| neighbor-id | (Optional) Neighbor ID |
| detail | Displays all neighbors given in detail (list all neighbors) |
EXEC
The following is sample output from the show ip ospf neighbor command showing a single line of summary information for each neighbor:
cs# show ip ospf neighbor
ID Pri State Dead Time Address Interface
199.199.199.137 1 FULL/DR 0:00:31 160.89.80.37 Ethernet0
192.31.48.1 1 FULL/DROTHER 0:00:33 192.31.48.1 Fddi0
192.31.48.200 1 FULL/DROTHER 0:00:33 192.31.48.200 Fddi0
199.199.199.137 5 FULL/DR 0:00:33 192.31.48.189 Fddi0
The following is sample output showing summary information about the neighbor that matches the Neighbor ID:
cs# show ip ospf neighbor 199.199.199.137
Neighbor 199.199.199.137, interface address 160.89.80.37
In the area 0.0.0.0 via interface Ethernet0
Neighbor priority is 1, State is FULL
Options 2
Dead timer due in 0:00:32
Link State retransmission due in 0:00:04
Neighbor 199.199.199.137, interface address 192.31.48.189
In the area 0.0.0.0 via interface Fddi0
Neighbor priority is 5, State is FULL
Options 2
Dead timer due in 0:00:32
Link State retransmission due in 0:00:03
If you specify the interface along with the Neighbor ID, the communication server displays the neighbors that match the Neighbor ID on the interface, as in the following sample display:
cs# show ip ospf neighbor ethernet 0 199.199.199.137
Neighbor 199.199.199.137, interface address 160.89.80.37
In the area 0.0.0.0 via interface Ethernet0
Neighbor priority is 1, State is FULL
Options 2
Dead timer due in 0:00:37
Link State retransmission due in 0:00:04
You can also specify the interface without the Neighbor ID to show all neighbors on the specified interface, as in the following sample display:
cs# show ip ospf neighbor fddi 0
ID Pri State Dead Time Address Interface
192.31.48.1 1 FULL/DROTHER 0:00:33 192.31.48.1 Fddi0
192.31.48.200 1 FULL/DROTHER 0:00:32 192.31.48.200 Fddi0
199.199.199.137 5 FULL/DR 0:00:32 192.31.48.189 Fddi0
The following is sample output from the show ip ospf neighbor detail command:
cs# show ip ospf neighbor detail
Neighbor 160.89.96.54, interface address 160.89.96.54
In the area 0.0.0.3 via interface Ethernet0
Neighbor priority is 1, State is FULL
Options 2
Dead timer due in 0:00:38
Neighbor 160.89.103.52, interface address 160.89.103.52
In the area 0.0.0.0 via interface Serial0
Neighbor priority is 1, State is FULL
Options 2
Dead timer due in 0:00:31
Table 18-31 describes significant fields shown in the previous displays.
| Field | Description |
|---|---|
| Neighbor x.x.x.x | Neighbor communication server ID. |
| interface address x.x.x.x | IP address of the interface. |
| In the area | Area and interface through which OSPF neighbor is known. |
| Neighbor priority | Communication server priority of neighbor, neighbor state. |
| State | OSPF state. |
| Options | Hello packet options field contents (E-bit only; possible values are 0 and 2; 2 indicates area is not a stub; 0 indicates area is a stub. |
| Dead timer | Expected time before communication server will declare neighbor dead. |
Use the show ip ospf virtual-links EXEC command to display the parameters and current state of OSPF virtual links.
show ip ospf virtual-linksThis command has no arguments or keywords.
EXEC
The information displayed by show ip ospf virtual-links is useful in debugging OSPF routing operations.
The following is sample output from the show ip ospf virtual-links command:
cs# show ip ospf virtual-links
Virtual Link to communication server 160.89.101.2 is up
Transit area 0.0.0.1, via interface Ethernet0, Cost of using 10
Transmit Delay is 1 sec, State POINT_TO_POINT
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 0:00:08
Adjacency State FULL
Table 18-32 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Virtual Link to communication server 160.89.101.2 is Up | Specifies the OSPF neighbor, and if the link to that neighbor is Up or Down. |
| Transit area 0.0.0.1 | The transit area through which the virtual link is formed. |
| via interface Ethernet0 | The interface through which the virtual link is formed. |
| Cost of using 10 | The cost of reaching the OSPF neighbor through the virtual link. |
| Transmit Delay is 1 sec | The transmit delay on the virtual link. |
| State POINT_TO_POINT | The state of the OSPF neighbor. |
| Timer intervals... | The various timer intervals configured for the link. |
| Hello due in 0:00:08 | When the next Hello is expected from the neighbor. |
| Adjacency State FULL | The adjacency state between the neighbors. |
To display information about interfaces configured for PIM, use the show ip pim interface EXEC command.
show ip pim interface [type number]| type | (Optional) Interface type. |
| number | (Optional) Interface number. |
EXEC
This command works only on interfaces that are configured for PIM.
The following is sample output from the show ip pim interface command:
cs> show ip pim interface
Address Interface Mode Neighbor Query DR
Count Interval
198.92.37.6 Ethernet0 Dense 2 30 198.92.37.33
198.92.36.129 Ethernet1 Dense 2 30 198.92.36.131
10.1.37.2 Tunnel0 Dense 1 30 0.0.0.0
Table 18-33 describes the fields shown in the display.
| Field | Description |
|---|---|
| Address | IP address of the next-hop communication server. |
| Interface | Interface type and number that is configured to run PIM. |
| Mode | Multicast mode in which the communication server is operating. This can be dense mode or sparse mode. |
| Neighbor Count | Number of PIM neighbors that have been discovered through this interface. |
| Query Interval | Frequency, in seconds, of PIM router-query messages, as set by the ip pim query-interval interface configuration command. The default is 30 seconds. |
| DR | IP address of the designated router on the LAN. Note that serial lines do not have designated routers, so the IP address is shown as 0.0.0.0. |
ip pim
show ip pim neighbor
To list the PIM neighbors discovered by the communication server, use the show ip pim neighbor EXEC command.
show ip pim neighbor [type number]| type | (Optional) Interface type. |
| number | (Optional) Interface number. |
EXEC
Use this command to determine which communication servers on the LAN are configured for PIM.
The following is sample output from the show ip pim neighbor command:
cs> show ip pim neighbor
PIM Neighbor Table
Neighbor Address Interface Uptime Expires
198.92.37.2 Ethernet0 17:38:16 0:01:25
198.92.37.33 Ethernet0 17:33:20 0:01:05 (DR)
198.92.36.131 Ethernet1 17:33:20 0:01:08 (DR)
198.92.36.130 Ethernet1 18:56:06 0:01:04
10.1.22.9 Tunnel0 19:14:59 0:01:09
Table 18-34 describes the fields shown in the display.
| Field | Description |
|---|---|
| Neighbor Address | IP address of the PIM neighbor. |
| Interface | Interface type and number on which the neighbor is reachable. |
| Uptime | How long in hours, minutes, and seconds the entry has been in the PIM neighbor table. |
| Expires | How long in hours, minutes, and seconds until the entry will be removed from the IP multicast routing table. |
| (DR) | Indicates that this neighbor is a designated router on the LAN. |
show ip pim interface
To display the rendezvous point (RP) communication servers associated with a sparse-mode multicast group, use the show ip pim rp EXEC command.
show ip pim rp [group-name | group-address]| group-name | (Optional) Name of the multicast group, as defined in the DNS hosts table. |
| group-address | (Optional) Address of the multicast group. This is a multicast IP address in four-part dotted notation. |
EXEC
The following is sample output from the show ip pim rp command from a communication server that is not an RP:
cs> show ip pim rp
Group: 224.2.127.255, number of RPs: 1
RP address: 198.92.37.2, state: Tunnel, uptime 0:01:25, expires in 0:03:04
The following is sample output from the show ip pim rp command from a communication server that is an RP:
cs# show ip pim rp
Group: 224.2.127.255, number of RPs: 1
RP address: 198.92.37.2, state: Up, next RP-reachable in 0:01:01
Table 18-35 explains the fields shown in the displays.
| Field | Description |
|---|---|
| Group: | Address of the multicast group. |
| number of RPs: | Number of RPs in the multicast group. |
| RP address: | Address of the RP. |
| state: | |
| uptime | |
| expires | |
| next RP-reachable in |
show ip mroute
Use the show ip protocols EXEC command to display the parameters and current state of the active routing protocol process.
show ip protocolsThis command has no arguments or keywords.
EXEC
The information displayed by show ip protocols is useful in debugging routing operations. Information in the Routing Information Sources field of the show ip protocols output can help you identify a communication server suspected of delivering bad routing information.
The following is sample output from the show ip protocols command, showing IGRP processes:
cs# show ip protocols
Routing Protocol is "igrp 109"
Sending updates every 90 seconds, next due in 44 seconds
Invalid after 270 seconds, hold down 280, flushed after 630
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
IGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
IGRP maximum hopcount 100
IGRP maximum metric variance 1
Redistributing: igrp 109
Routing for Networks:
198.92.72.0
Routing Information Sources:
Gateway Distance Last Update
198.92.72.18 100 0:56:41
198.92.72.19 100 6d19
198.92.72.22 100 0:55:41
198.92.72.20 100 0:01:04
198.92.72.30 100 0:01:29
Distance: (default is 100)
Routing Protocol is "bgp 1878"
Sending updates every 60 seconds, next due in 0 seconds
Outgoing update filter list for all interfaces is 1
Incoming update filter list for all interfaces is not set
Redistributing: igrp 109
IGP synchronization is disabled
Automatic route summarization is enabled
Neighbor(s):
Address FiltIn FiltOut DistIn DistOut Weight RouteMap
192.108.211.17 1
192.108.213.89 1
198.6.255.13 1
198.92.72.18 1
198.92.72.19
198.92.84.17 1
Routing for Networks:
192.108.209.0
192.108.211.0
198.6.254.0
Routing Information Sources:
Gateway Distance Last Update
198.92.72.19 20 0:05:28
Distance: external 20 internal 200 local 200
Table 18-36 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Routing Protocol is "igrp 109" | Specifies the routing protocol used. |
| Sending updates every 90 seconds | Specifies the time between sending updates. |
| next due in 88 seconds | Precisely when the next update is due to be sent. |
| Invalid after 270 seconds | Specifies the value of the invalid parameter. |
| hold down for 280 | Specifies the current value of the hold-down parameter. |
| flushed after 630 | Specifies the time in seconds after which the individual routing information will be thrown (flushed) out. |
| Outgoing update... | Specifies whether the outgoing filtering list has been set. |
| Incoming update ... | Specifies whether the incoming filtering list has been set. |
| Default networks | Specifies how these networks will be handled in both incoming and outgoing updates. |
| IGRP metric | Specifies the value of the K0-K5 metrics as well as the maximum hopcount. |
| Redistributing | Lists the protocol that is being redistributed. |
| Routing | Specifies the networks that the routing process is currently injecting routes for. |
| Routing Information Sources | Lists all the routing sources the communication server is using to build its routing table. For each source, you will see displayed:
|
Use the show ip route EXEC command to display the current state of the routing table.
show ip route [ip-address [mask] | protocol [process-id]]| ip-address | (Optional) Address about which to display routing information. |
| mask | (Optional) Subnet mask of the subnet about which to display routing information. |
| protocol | (Optional) Name of a routing protocol; or the keyword connected, static, or summary. If you specify a routing protocol, use one of the following keywords: bgp, egp, eigrp, hello, igrp, isis, ospf, or rip. |
| process-id | (Optional) Identifier of the particular routing protocol process. |
EXEC
The following is sample output from the show ip route command when entered without an address:
cs# show ip route
Codes: I - IGRP derived, R - RIP derived, O - OSPF derived
C - connected, S - static, E - EGP derived, B - BGP derived
* - candidate default route, IA - OSPF inter area route
E1 - OSPF external type 1 route, E2 - OSPF external type 2 route
Gateway of last resort is 131.119.254.240 to network 129.140.0.0
O E2 150.150.0.0 [160/5] via 131.119.254.6, 0:01:00, Ethernet2
E 192.67.131.0 [200/128] via 131.119.254.244, 0:02:22, Ethernet2
O E2 192.68.132.0 [160/5] via 131.119.254.6, 0:00:59, Ethernet2
O E2 130.130.0.0 [160/5] via 131.119.254.6, 0:00:59, Ethernet2
E 128.128.0.0 [200/128] via 131.119.254.244, 0:02:22, Ethernet2
E 129.129.0.0 [200/129] via 131.119.254.240, 0:02:22, Ethernet2
E 192.65.129.0 [200/128] via 131.119.254.244, 0:02:22, Ethernet2
E 131.131.0.0 [200/128] via 131.119.254.244, 0:02:22, Ethernet2
E 192.75.139.0 [200/129] via 131.119.254.240, 0:02:23, Ethernet2
E 192.16.208.0 [200/128] via 131.119.254.244, 0:02:22, Ethernet2
E 192.84.148.0 [200/129] via 131.119.254.240, 0:02:23, Ethernet2
E 192.31.223.0 [200/128] via 131.119.254.244, 0:02:22, Ethernet2
E 192.44.236.0 [200/129] via 131.119.254.240, 0:02:23, Ethernet2
E 140.141.0.0 [200/129] via 131.119.254.240, 0:02:22, Ethernet2
E 141.140.0.0 [200/129] via 131.119.254.240, 0:02:23, Ethernet2
Table 18-37 describes significant fields shown in this display.
| Field | Description |
|---|---|
| O | Indicates protocol that derived the route. Possible values include the following:
|
|
E2 | Type of route. Possible values include the following:
|
|
150.150.0.0 | Indicates the address of the remote network. |
| [160/5] | The first number in the brackets is the administrative distance of the information source; the second number is the metric for the route. |
| via 131.119.254.6 | Specifies the address of the next communication server to the remote network. |
| 0:01:00 | Specifies the last time the route was updated in hours:minutes:seconds. |
| Ethernet 2 | Specifies the interface through which the specified network can be reached. |
| * | Indicates the last path used when a packet was forwarded. It pertains only to the nonfast-switched packets. However, it does not indicate what path will be used next when forwarding a nonfast-switched packet except when the paths are equal cost. |
When you specify that you want information about a specific network displayed, more detailed statistics are shown. The following is sample output from the show ip route command when entered with the address 131.119.0.0.
cs# show ip route 131.119.0.0
Routing entry for 131.119.0.0 (mask 255.255.0.0)
Known via "igrp 109", distance 100, metric 10989
Tag 0
Redistributing via igrp 109
Last update from 131.108.35.13 on TokenRing0, 0:00:58 ago
Routing Descriptor Blocks:
* 131.108.35.13, from 131.108.35.13, 0:00:58 ago, via TokenRing0
Route metric is 10989, traffic share count is 1
Total delay is 45130 microseconds, minimum bandwidth is 1544 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 2/255, Hops 4
Table 18-38 describes significant fields shown in this display.
| Field | Description |
|---|---|
| Routing entry for 131.119.0.0 (mask 255.255.0.0) | Network number and mask. |
| Known via "igrp 109" | Indicates how the route was derived. |
| distance 100 | Administrative distance of the information source. |
| Tag 0 | Integer that is used to implement the route. |
| Redistributing via igrp 109 | Indicates redistribution protocol. |
| Last update from 131.108.35.13 on TokenRing0 | Indicates the IP address of a communication server that is the next hop to the remote network and the communication server interface on which the last update arrived. |
| 0:00:58 ago | Specifies the last time the route was updated in hours:minutes:seconds. |
| 131.108.35.13, from 131.108.35.13, 0:00:58 ago | Indicates the next hop address, the address of the gateway that sent the update, and the time that has elapsed since this update was received in hours:minutes:seconds. |
| via TokenRing0 | Interface for this route. |
| Route metric is 10989 | This value is the best metric for this routing descriptor block. |
| traffic share count is 1 | Number of uses for this routing descriptor block. |
| Total delay is 45130 microseconds | Total propagation delay in microseconds. |
| minimum bandwidth is 1544 Kbit | Minimum bandwidth encountered when transmitting data along this route. |
| Reliability 255/255 | Likelihood of successful packet transmission expressed as a number between 0 and 255 (255 is 100% reliability). |
| minimum MTU 1500 bytes | Smallest MTU along the path. |
| Loading 2/255 | Effective bandwidth of the route in kilobits per second/255 is saturation. |
| Hops 4 | Hops to the destination or to the communication server where the route first enters IGRP. |
A dagger (+) indicates that the command is documented in another chapter.
show interfaces tunnel +
show ip route summary
Use the show ip route summary EXEC command to display the current state of the routing table.
show ip route summaryThis command has no arguments or keywords.
EXEC
The following is sample output from the show ip route summary command:
cs# show ip route summary
Route Source Networks Subnets Overhead Memory (bytes)
connected 0 3 126 360
static 1 2 126 360
igrp 109 747 12 31878 91080
internal 3 360
Total 751 17 32130 92160
cs#
Table 18-39 describes the fields shown in the display:
| Field | Description |
|---|---|
| Route Source | Routing protocol name, or connected, static, or internal. Internal--those routes that are in the primary routing table merely as markers to hold subnet routes. These routes are not owned by any routing protocol. There should be one of these internal routes for each subnetted network in the routing table. |
| Networks | The number of Class A, B, or C networks that are present in the routing table for each route source. |
| Subnets | The number of subnets that are present in the routing table for each route source, including host routes. |
| Overhead | Any additional memory involved in allocating the routes for the particular route source other than the memory specified under "Memory." |
| Memory | The number of bytes allocated to maintain all the routes for the particular route source. |
show ip route
Use the show ip route supernets-only privileged EXEC command to display information about supernets.
show ip route supernets-onlyPrivileged EXEC
The following is sample output from the show ip route supernets-only command:
cs# show ip route supernets-only
Codes: I - IGRP derived, R - RIP derived, O - OSPF derived
C - connected, S - static, E - EGP derived, B - BGP derived
i - IS-IS derived, D - EIGRP derived
* - candidate default route, IA - OSPF inter area route
E1 - OSPF external type 1 route, E2 - OSPF external type 2 route
L1 - IS-IS level-1 route, L2 - IS-IS level-2 route
EX - EIGRP external route
Gateway of last resort is not set
B 198.92.0.0 (mask is 255.255.0.0) [20/0] via 198.92.72.30, 0:00:50
B 192.0.0.0 (mask is 255.0.0.0) [20/0] via 198.92.72.24, 0:02:50
This display shows supernets only; it does not show subnets.
Use the show route-map EXEC command to display all route-maps configured or only the one specified.
show route-map [map-name]| map-name | (Optional) Name of a specific route-map |
EXEC
The following is sample output from the show route-map command:
cs# show route-map
route-map foo, permit, sequence 10
Match clauses:
tag 1 2
Set clauses:
metric 5
route-map foo, permit, sequence 20
Match clauses:
tag 3 4
Set clauses:
metric 6
Table 18-40 describes the fields shown in the display:
| Field | Description |
|---|---|
| route-map | Name of the route-map. |
| permit | Indicates that the route is redistributed as controlled by the set actions. |
| sequence | Number that indicates the position a new route map is to have in the list of route maps already configured with the same name. |
| Match clauses tag | Match criteria--conditions under which redistribution is allowed for the current route-map. |
| Set clauses metric | Set actions--the particular redistribution actions to perform if the criteria enforced by the match commands are met. |
redistribute
route-map
Use the synchronization router configuration command to disable the synchronization between BGP and your IGP. Use the no form of this command to enable a communication server to advertise a network route without waiting for the IGP.
synchronizationThis command has no arguments or keywords.
Enabled
Router configuration
Usually, a BGP speaker does not advertise a route to an external neighbor unless that route is local or exists in the IGP. The no synchronization command allows a communication server to advertise a network route without waiting for the IGP. This feature allows communication servers within an autonomous system to have the route before BGP makes it available to other autonomous systems.
Use synchronization if there are communication servers in the autonomous system that do not speak BGP.
The following example enables the communication server to advertise a network route without waiting for the IGP:
router bgp 120
no synchronization
Use the table-map router configuration command to modify metric and tag values when the IP routing table is updated with BGP learned routes. Use the no form of this command to disable this function.
table-map route-map-name| route-map-name | Route map name, from the route-map command. |
Disabled
Router configuration
This command adds the route map name defined by the route-map command to the IP routing table. This command is used to set the tag name and the route metric to implement redistribution.
You can use match clauses of route maps in the table-map command. IP access list, autonomous system paths, and next-hop match clauses are supported.
In the following example, the communication server is configured to automatically compute the tag value for the BGP learned routes and to update the IP routing table.
route-map tag
match as path 10
set automatic-tag
!
router bgp 100
table-map tag
match as-path
match ip address
match ip next-hop
route-map
Use the timers basic router configuration command to adjust EGP, RIP, or IGRP network timers. Use the no form of this command to restore the defaults.
timers basic update invalid holddown flush [sleeptime]| update | Rate (in seconds) at which updates are sent. This is the fundamental timing parameter of the routing protocol. |
| invalid | Interval of time (in seconds) after which a route is declared invalid; it should be three times the value of update. A route becomes invalid when there is an absence of updates that refresh the route. The route then enters holddown. The route is marked inaccessible and advertised as unreachable. However, the route is still used for forwarding packets. |
| holddown | Interval (in seconds) during which routing information regarding better paths is suppressed. It should be at least three times the value of update. A route enters into a holddown state when an update packet is received that indicates the route is unreachable. The route is marked inaccessible and advertised as unreachable. However, the route is still used for forwarding packets. When holddown expires, routes advertised by other sources are accepted and the route is no longer inaccessible. |
| flush | Amount of time (in seconds) that must pass before the route is removed from the routing table; the interval specified must be at least the sum of invalid and holddown. If it is less than this sum, the proper holddown interval cannot elapse, which results in a new route being accepted before the holddown interval expires. |
| sleeptime | (Optional) For IGRP only, interval (in milliseconds) for postponing routing updates in the event of a flash update. The sleeptime value should be less than the update time. If the sleeptime is greater than the update time, routing tables will become unsynchronized. |
| Protocol | update | invalid | holddown | flush | sleeptime |
|---|---|---|---|---|---|
| EGP | N/A | 1080 | N/A | 1200 | N/A |
| RIP | 30 | 180 | 180 | 240 | N/A |
| IGRP | 90 | 270 | 280 | 630 | 0 |
Router configuration
The basic timing parameters for IGRP, EGP, and RIP are adjustable. Since these routing protocols are executing a distributed, asynchronous routing algorithm, it is important that these timers be the same for all communication servers in the network.
In the following example, updates are broadcast every 5 seconds. If a communication server is not heard from in 15 seconds, the route is declared unusable. Further information is suppressed for an additional 15 seconds. At the end of the suppression period, the route is flushed from the routing table.
router igrp 109
timers basic 5 15 15 30
Note that by setting a short update period, you run the risk of congesting slow-speed serial lines; however, this is not a big concern on faster-speed Ethernets and T1-rate serial lines. Also, if you have many routes in your updates, you can cause the communication servers to spend an excessive amount of time processing updates.
When the timers basic command is used with EGP, the update time and holddown time are ignored. For example, the commands that follow will set the invalid time for EGP to 100 seconds and the flush time to 200 seconds.
router egp 47
timers basic 0 100 0 200
Use the timers bgp router configuration command to adjust BGP network timers. Use the no form of this command to reset the BGP timing defaults.
timers bgp keepalive holdtime| keepalive | Frequency, in seconds, with which the communication server sends keepalive messages to its peer. The default is 60 seconds. |
| holdtime | Interval, in seconds, after not receiving a keepalive message that the communication server declares a peer dead. The default is 180 seconds. |
keepalive timer = 60 seconds
holdtime timer = 180 seconds
Router configuration
The following example changes the keepalive timer to 70 seconds and the holdtime timer to 210 seconds:
timers bgp 70 210
clear ip bgp
router bgp
show ip bgp
Use the timers egp router configuration command to adjust EGP Hello and polltime network timers. Use the no form of this command to reset the EGP timing defaults.
timers egp hello polltime| hello | Frequency, in seconds, with which the communication server sends Hello messages to its peer. The default is 60 seconds. |
| polltime | Interval, in seconds, for how frequently to exchange updates. The default is 180 seconds. |
Hello timer = 60 seconds
polltime timer = 180 seconds
Router configuration
To change the invalid time or flush time for EGP routes, use the timers basic router configuration command.
The following example changes the EGP timers to 2 minutes and 5 minutes, respectively:
timers egp 120 300
router egp
show ip egp
timers basic
Use the traffic-share router configuration command to control how traffic is distributed among routes when there are multiple routes for the same destination network that have different costs. Use the no form of this command to disable this function.
traffic-share {balanced | min}| balanced | Distributes traffic proportionately to the ratios of the metrics. |
| min | Uses routes that have minimum costs. |
Traffic is distributed proportionately to the ratios of the metrics.
Router configuration
This command applies to IGRP and Enhanced IGRP routing protocols only. With the default setting, routes that have higher metrics represent less-preferable routes and get less traffic. Configuring traffic-share min causes the communication server to divide traffic among the routes with the best metric. Other routes will remain in the routing table, but will receive no traffic.
In the following example, only routes of minimum cost will be used:
router igrp 5
traffic-share min
Use the validate-update-source router configuration command to cause the communication server to validate the source IP address of incoming routing updates for RIP and IGRP routing protocols. Use the no form of this command to disable this validate function for RIP or IGRP.
validate-update-sourceThis command has no arguments or keywords.
Enabled
Router configuration
This command is only applicable to RIP and IGRP. The communication server ensures that the source IP address of incoming routing updates is on the same IP network as one of the addresses defined for the receiving interface.
Disabling split horizon on the incoming interface will also cause the system to perform this validation check.
For unnumbered IP interfaces (interfaces configured as ip unnumbered), no checking is performed.
In the following example, the communication server is configured to perform no validation checks on the source IP address of incoming RIP updates:
router rip
network 128.105.0.0
no validate-update-source
Use the variance router configuration command to control load balancing in an IGRP-based internet. Use the no form of this command to reset variance to the default value.
variance multiplier| multiplier | Metric value used for load balancing. It can be a value from 1 to 128. The default is 1, which means equal-cost load balancing. |
1 (equal-cost load balancing)
Router configuration
Setting this value lets the communication server determine the feasibility of a potential route. A route is feasible if the next communication server in the path is closer to the destination than the current communication server and if the metric for the entire path is within the variance. Only paths that are feasible can be used for load balancing and included in the routing table.
If the following two conditions are met, the route is deemed feasible and can be added to the routing table:
The following example sets a variance value of 4:
router igrp 109
variance 4
|
|