Verifying Adjacent Routers
Purpose
Verify that routers are adjacent and able to exchange IS-IS data.
Action
To verify that routers are adjacent and able to exchange IS-IS data, enter the following CLI operational mode command:
The following sample output shows the adjacencies that formed for all routers shown in Displaying the Status of IS-IS Adjacencies .
Sample Output
user@R1> show isis adjacency Interface System L State Hold (secs) SNPA so-0/0/0.0 R2 2 Up 19 so-0/0/1.0 R5 2 Up 18 user@R2> show isis adjacency Interface System L State Hold (secs) SNPA so-0/0/0.0 R1 2 Up 19 so-0/0/1.0 R3 1 Up 26 so-0/0/2.0 R6 2 Up 21 user@R3> show isis adjacency Interface System L State Hold (secs) SNPA so-0/0/1.0 R2 1 Up 24 user@R4> show isis adjacency Interface System L State Hold (secs) SNPA so-0/0/2.0 R5 1 Up 23 user@R5> show isis adjacency Interface System L State Hold (secs) SNPA so-0/0/0.0 R6 2 Up 22 so-0/0/1.0 R1 2 Up 20 so-0/0/2.0 R4 1 Up 20 user@R6> show isis adjacency Interface System L State Hold (secs) SNPA so-0/0/0.0 R5 2 Up 21 so-0/0/2.0 R2 2 Up 20
Meaning
The sample output shows the adjacencies that formed in the network illustrated in Displaying the Status of IS-IS Adjacencies . The Level 1/Level 2 routers (R2 and R5) formed Level 1 adjacencies with Level 1 routers (R3 and R4), and Level 2 adjacencies with the Level 2 routers (R1 and R6). To view the status of the adjacency, examine the State column. In this example, all adjacencies in the network are up.
If the state is not Up for a particular neighbor, you must first examine the IS-IS configuration for the particular interface. Make sure that the NET address is correct and that the loopback interface (lo0) is configured. Use the show isis interface or show isis interface detail command to display the IS-IS parameters for all interfaces configured with IS-IS. With these two commands, you can see which interfaces are configured for IS-IS, whether they are configured for Level 1 or Level 2, the IS-IS metric, and other IS-IS information.
