Protocol Statements (TCP/IP Network Administration, 3rd Edition)

B.8.1. The ospf Statement

ospf yes | no | on | off  [{
  defaults {
    preference preference ;
    cost cost ;
    tag [as] tag ;
    type 1 | 2 ;
    inherit-metric; } ;
  exportlimit routes ;
  exportinterval time ;
  traceoptions trace_options ; 
  syslog [first count] [every count];
  monitorauthkey key ;
  backbone | area number {
    authtype 0 | 1 | none | simple ;
    stub [cost cost]  ;
    networks {
     address [mask mask | masklen number] [restrict]  ;
     host address [restrict]  ; } ;
    stubhosts { 
     address cost cost ; } ;
    interface interface_list [nonbroadcast] [cost cost]  {
     pollinterval time ;
     routers {
     address [eligible]  ; } ;
     interface_parameters } ;
    virtuallink neighborid router_id transitarea area {
     interface_parameters } ;
 } ; } ] ;

The ospf statement enables or disables the Open Shortest Path First (OSPF) routing protocol. By default, OSPF is disabled. It is enabled by specifying yes or on (it doesn't matter which you use) and it is disabled with no or off.

WARNING: For the sake of brevity, this text explains only the first occurrence of any gated.conf parameter if it is used the same way in subsequent commands. Only differences between commands are explained. For example, yes | no | on | off is not explained again because it is always used in the same way to enable or disable a protocol.

The ospf statement has many configuration parameters:

defaults

Defines the defaults used when importing OSPF routes from an external autonomous system and announcing those routes to other OSPF routers. The link-state advertisement (LSA) used to announce these routes is called an ASE (autonomous system external) because it contains routes from external autonomous systems. See the description of OSPF in Chapter 7, "Configuring Routing ".

preference preference: Defines the preference of OSPF ASE routes. The default is 150.
cost cost: Defines the cost used when advertising a non-OSPF route in an ASE. The default is 1.
tag [as] tag: Defines the OSPF ASE tag value. The tag is not used by the OSPF protocol but may be used by an export policy to filter routes. (See the export statement later in this appendix.) When the as keyword is specified, the tag field may contain AS path information.
type 1 | 2: Defines the type of ASE used. The default is type 1. Type 1 contains routes learned from an external protocol that provides a metric directly comparable to the OSPF metric. The metric is added to the cost of reaching the border router when routes are advertised. A type 2 ASE contains routes learned from an exterior gateway protocol that does not provide a routing metric comparable to the OSPF metric. These routes are advertised with the cost of reaching the border router. See Chapter 7, "Configuring Routing ".
inherit-metric: Directs gated to use the external metric for ASE routes if no metric is defined in the export statement.

exportlimit routes

Defines the maximum number of ASE LSAs that will be flooded at one time. The default is 100.

exportinterval time

Defines how frequently ASE link-state advertisements are flooded to the network. The default is once per second.

traceoptions trace_options

Defines the tracing used to debug OSPF. In addition to the standard trace flags, OSPF supports:

lsabuild: Traces construction of link-state advertisements (LSAs).
spf: Traces the Shortest Path First (SPF) calculations.
hello: Traces the OSPF HELLO packets.
dd: Traces the OSPF Database Description packets.
request: Traces the OSPF Link-State Request packets.
lsu: Traces the OSPF Link-State Update packets.
ack: Traces the OSPF Link-State Ack packets.

syslog [first number] [every count]

Defines packet capture parameters. first specifies the number of packets captured for each type of OSPF packet. every specifies how often packets are captured after the initial group is captured. For example, if count is set to 50, every fiftieth packet of each type is captured.

monitorauthkey password

Defines the password used for ospf_monitor queries. By default these queries are not authenticated. If monitorauthkey is specified, incoming queries must contain the specified password.

backbone | area number

Defines the OSPF area of which this router is a member. Every router must belong to an area. If more than one area is configured, at least one must be the backbone. The backbone is defined using the backbone keyword. All other areas are defined by the area keyword and the number of the area, e.g., area 1. See Chapter 7, "Configuring Routing " for a discussion of OSPF areas. Several configuration parameters are associated with each area:

stub [cost cost]: Specifies that this is a stub area. A stub area is one in which there are no ASE routes. If a cost is specified, it is used to advertise a default route into the stub area.
networks: Defines the range of networks contained within this area. The specified ranges are advertised into other areas as summary network LSAs and not as inter-area routes. If restrict is specified, the summary network LSAs are not advertised. The entries in the networks list are either specified as a host address by using the host keyword before the address, or as a network address by simply specifying the address. An address mask can be defined for a network address. The mask can be defined in dotted decimal notation using the mask keyword or as a numeric prefix length using the masklen keyword. The address masks mask 255.255.0.0 and masklen 16 are equivalent. If no address mask is specified, the natural mask is used. This option can reduce the amount of routing information propagated between areas.

stubhosts

Lists the directly attached hosts, and their costs, that should be advertised as reachable from this router. List point-to-point interfaces here.

interface interface_list [nobroadcast] [cost cost]

Defines the interfaces used by OSPF. If the keyword nobroadcast is specified, the interface connects to a nonbroadcast multiple access (NBMA) network. If nobroadcast is not used, the interface connects to a broadcast or a point-to-point network. Specify the cost of the interface with the cost keyword, e.g., cost 5. The default cost is 1. Two options are specific to NBMA interfaces:

pollinterval time: Defines the time interval at which OSPF HELLO packets are sent to neighbors.
routers: Lists all neighbors by address. The eligible keyword indicates if the neighbor can become a designated router.

All interfaces -- NBMA and broadcast -- can use these parameters:

enable | disable ;: Enables or disables the interface.
retransmitinterval time ;: Defines the number of seconds between link-state advertisement retransmissions.
transitdelay time ;: Defines the estimated number of seconds required to transmit a link-state update over this interface. It must be greater than 0.
priority priority ;

virtuallink neighborid router_id transitarea area

Defines a virtual link for the backbone area. The router_id is the router identifier of the remote router at the other end of the virtual link. The transit area must be one of the other areas configured on this system. All standard interface parameters defined above may be specified on a virtual link.

rip yes | no | on | off [ { broadcast ; nobroadcast ; nocheckzero ; preference preference ; defaultmetric metric ; query authentication [none | [simple | md5 password]] ; interface interface_list [noripin] | [ripin] [noripout] | [ripout] [metricin metric] [metricout metric] [version 1 | 2 [multicast | broadcast]] [[secondary] authentication [none | [simple | md5 password]] ; trustedgateways gateway_list ; sourcegateways gateway_list ; traceoptions trace_options ; } ] ;

isis on | off { [ area areaid ; ] [ area auth simple key ; ] [ domain auth simple key ; ] [ domain-wide on | off ; ] [ export-defaults ; ] [ export-defaults level 1 | 2 ; ] [ export-defaults metric metric | inherit ; ] [ export-defaults metric-type internal | external ; ] [ external preference preference ; ] [ level 1 | 2 | 1 and 2 ; ] [ interface name | address [ { [ enable | disable ; ] [ auth simple key ; ] [ csn-interval interval [ level 1 | 2 | 1 and 2 ] ; ] [ dis-hello-interval interval [ level 1 | 2 | 1 and 2 ] ; ] [ encap [ iso | ip ] ; ] [ hello-interval interval [ level 1 | 2 | 1 and 2 ] ; ] [ hello-multiplier number [ level 1 | 2 | 1 and 2 ] ; ] [ lsp-interval interval ; ] [ level 1 | 2 | 1 and 2 ; ] [ max-burst number ; ] [ metric metric [ level 1 | 2 | 1 and 2 ] ; ] [ passive on | off ; ] [ priority priority [ level 1 | 2 | 1 and 2 ] ; ] [ retransmit-interval interval ; ] } ] ; ] [ overload-bit on | off ; ] [ preference preference ; ] [ psn-interval intervalt ; ] [ require-snp-auth on | off ; ] [ ribs unicast | unicast multicast ; ] [ spf-interval interval ; ] [ inet6 on | off ; ] [ summary-originate [ inet | inet6 ] { [network (mask mask | masklen n ) metric cost-value ; ] } ; ] [ summary-filter [ inet | inet6 ] { [network mask mask | masklen number ; ] } ; ] [ systemid systemid ; ] [ traceoptions traceoptions ; ] [ config-time seconds ; ] [ es-config-time seconds ; ] [ hold-time seconds ; ] };

bgp yes | no | on | off [{ preference preference ; defaultmetric metric ; traceoptions trace_options ; group type external peeras as_number | internal peeras as_number | igp peeras as_number proto proto | routing peeras as_number proto proto interface interface_list | test peeras as_number { allow { address mask mask | masklen number all host address } ; peer address [metricout metric] [localas as_number] [nogendefault] [gateway address] [preference preference] [preference2 preference] [lcladdr address] [holdtime time] [version number] [passive] [sendbuffer number] [recvbuffer number] [indelay time] [outdelay time] [keep all | none] [showwarnings] [noaggregatorid] [keepalivesalways] [v3asloopokay] [nov4asloop] [logupdown] [ttl ttl] [traceoptions trace_options] ; } ; }] ;

egp yes | no | on | off [{ preference preference ; defaultmetric metric ; packetsize maxpacketsize ; traceoptions trace_options ; group [peeras as_number] [localas as_number] [maxup number] { neighbor address [metricout metric] [preference preference] [preference2 preference] [ttl ttl] [nogendefault] [importdefault] [exportdefault] [gateway address] [lcladdr address] [sourcenet network] [minhello | p1 interval] [minpoll | p2 interval] [traceoptions trace_options] ; } ; }] ;

routerdiscovery server yes | no | on | off [{ traceoptions trace_options ; interface interface_list [minadvinterval time] [maxadvinterval time] [lifetime time] ; address interface_list [advertise | ignore] [broadcast | multicast] [ineligible | preference preference] ; } ] ;

routerdiscovery client yes | no | on | off [{ traceoptions trace_options ; preference preference ; interface interface_list [enable | disable | multicast] [quiet | solicit] ; } ] ;

kernel { options [nochange] [noflushatexit] [protosync]; remnantholdtime ; routes number ; flash [limit number] [type interface | interior | all] ; background [limit number] [priority flash | higher | lower] ; traceoptions trace_options ; } ;

B.8. Protocol Statements

B.8.1. The ospf Statement

B.8.2. The rip Statement

B.8.3. The isis Statement

B.8.4. The bgp Statement

B.8.5. The egp Statement

B.8.6. The smux Statement

B.8.7. The redirect Statement

B.8.8. The icmp Statement

B.8.9. The routerdiscovery Statement

B.8.9.1. The routerdiscovery client statement

B.8.10. The kernel Statement