Note For more software configuration information about tag switching, refer to the
ATM Switch Router Software Configuration Guide. Refer to the ATM Switch Router
Command Reference publication for command syntax.
Software Restrictions
The software restrictions for tag switching follow:
Open Shortest Path First (OSPF) is the only routing protocol currently supported.
IP is the only network layer protocol currently supported.
Configuring Tag Switching on an ATM Switch Router
This section describes how to configure tag switching on an ATM switch router, and includes the following procedures:
Note Configure all parallel interfaces between switches for either IP unnumbered or with
a specific IP address. Unnumbering some parallel interfaces and assigning specific IP
addresses to others might cause Tag Distribution Protocol (TDP)
sessions to restart on some parallel interfaces when another parallel interface is shut down.
Therefore, we highly recommend that you unnumber all parallel interfaces to loopback.
Take these steps:
Step
Command
Purpose
1
Switch(config)# interface atmcard/subcard/port
Switch(config-if)#
Enter interface configuration mode on the specified ATM interface.
2
Switch(config-if)# ip unnumberedtype number
Enable IP unnumbered on the ATM interface and assign the unnumbered interface to an interface that has an IP address. We recommend enabling IP unnumbered because it allows you to conserve IP addresses and reduces the number of TVCs1 terminating on the switch.
or
or
Switch(config-if)# ip addressip-address mask
Assign an IP address and subnet mask to the ATM interface.
3
Switch(config-if)# tag-switching ip
Enable tag switching of IP packets on the interface.
Switch(config-if)# ip address 1.3.11.3 255.255.0.0
Switch(config-if)# tag-switching ip
Switch(config-if)# exit
Switch(config)#
Verify
Switch# show tag-switching interfaces
Interface IP Tunnel Operational
ATM0/0/3 Yes No No (ATM tagging)
ATM1/0/1 Yes No No (ATM tagging)
Switch#
Configuring the Routing Protocol
Enable the routing protocol (OSPF) on the ATM switch router so that it can create routing tables, which identify routes through the network. Then add the addresses and associated routing areas to the routing process so that it can propagate the addresses to other ATM switches and routers.
Take these steps:
Step
Command
Purpose
1
Switch(config)# routerospfprocess_number
Enable the routing protocol and assign it a process number. The process number is any positive integer.
Define the network prefix, a wildcard subnet mask, and the associated area number on which to run the routing protocol. An area number is an identification number for an address range.
Repeat this command for each additional area you want to add to the routing process.
Caution Ethernet interface 0 on the processor card (CPU card) is used for system management only (for example, downloading system images or configuration files from a TFTP1 server). Do not add this interface to the routing process.
Note An IP address of 1.1.1.1 with a subnet mask of 255.255.255.0 is entered as an IP
network prefix of 1.1.1.0 with a subnet mask of 0.0.0.255. Likewise, an IP address of
1.2.1.1 with a subnet mask of 255.255.255.0 is entered as an IP network prefix of 1.2.1.0
with a subnet mask of 0.0.0.255.
Switch(config)# router ospf 10000
Switch(config-router)# network 1.1.1.0 0.0.0.255 area 0
Switch(config-router)# network 1.2.1.0 0.0.0.255 area 0
Switch(config-router)# network 1.3.0.0 0.0.255.255 area 0
Switch(config-router)# network 200.2.2.0 0.0.0.255 area 0
Switch(config-router)# network 1.0.1.0 0.0.0.255 area 0
Switch(config-router)# network 1.18.0.0 0.0.255.255 area 0
Switch(config-router)# exit
Switch(config)#
Verify
Switch# show ip ospf
Routing Process "ospf 10000" with ID 1.0.1.11
Supports only single TOS(TOS0) routes
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Number of DCbitless external LSA 0
Number of DoNotAge external LSA 0
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Area BACKBONE(0) (Inactive)
Number of interfaces in this area is 4
Area has no authentication
SPF algorithm executed 2 times
Area ranges are
Link State Update Interval is 00:30:00 and due in 00:14:42
Link State Age Interval is 00:20:00 and due in 00:14:10
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Switch#
Configuring Tag Switching on a Router
This section describes how to configure tag switching between a router and an ATM switch router.