Case Study: Troubleshooting IS-IS Neighbor Relationships
In two instances, IS-IS does not form neighbor adjacencies correctly. The first is with miscon-figured NSAPs. For example, Router C has just been attached to the network in Figure 5-17, and it is not forming L1 adjacencies with Routers A and B as expected. Figure 5-17. IS-IS Neighbors in Different Areas On Router A, you see the output in Example 5-12. Example 5-12. Determining IS Adjacency Types router-a#show clns neighbor System Id SNPA&n..
Connecting VLAN Trunks with ISL
The following set of commands allows you to connect an ISL trunk to your router: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#interface FastEthernet0/0 Router1(config-if)#no ip address Router1(config-if)#speed 100 Router1(config-if)#full-duplex Router1(config-if)#exit Router1(config)#interface FastEthernet0/0.1 Router1(config-subif)#encapsulation isl 1 Router1(config-subif)#ip address 172.25.1.5 255.255.255.0 R..
If you want to increase the number of VTY ports available on the router for remote access, create a reference to the additional lines in the configuration as follows: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z.Router1(config)#line vty 0 9Router1(config-line)#exitRouter1(config)#endRouter1# This command defines the characteristics for a range of VTY ports from 0 to 9. Since ports 0 to 4 exist by default, this has the effect of ..
Using MSDP to Discover External Sources
The typical way to configure Multicast Source Discovery Protocol (MSDP) involves first selecting one of your MBGP routers as the RP for your internal network. Then you set up an MSDP peer relationship with the RP in another Autonomous System, which is usually an MBGP peer router in the next domain. The following configuration includes commands required to configure the router as an RP for the internal network using BSR: Router-ASBR1#configure terminal Enter configuration c..
Disabling EIGRP on an Interface
You can prevent an interface from participating in EIGRP by simply designating it as passive: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z.Router1(config)#router eigrp 55Router1(config-router)#passive-interface Serial0/1Router1(config-router)#exitRouter1(config)#endRouter1# The passive-interface command in EIGRP prevents directly connected routers from establishing an EIGRP neighbor relationship. Since they can't become neighbor..
