This chapter gives an short overview of the common used commands for verifying and troubleshooting the IS-IS configuration. Most of the commands are used in the practical part of this paper. Therefore, please take a look at the lab exercises.

sh ver: hardware and operating system details of the router
sh run: most problems based on a misconfiguration of the routing process. With this command it is possible to check the running configuration
sh isis route: IS-IS routes
sh clns route: Clns routes
sh clns traffic: Statistic information
sh clns protocol Information about the routing process
sh clns neighbors: Provides information about adjacencies
sh clns interface: Provides information about the clns interface and the interface status
sh isis database: Level 1 and level 2 link state database
sh isis topology: A view of the known network topology
sh isis spf-log: SPF triggers and duration of events

debug isis adj-packets: Displays the sending and receiving of hello packets in real time
debug isis update-packets: Displays real time information about network changes (LSPs and CSNPs)
debug spf-events: Displays real time information about the SPF process

ping
traceroute
ping clns: If the CLNP process is activated (with the “clns router isis” command) this is the equivalent to the normal ping command
traceroute clns: If the CLNP process is activated (with the “clns router isis” command) this is the equivalent to the normal traceroute command

For a full description of these commands type the command with a ”?” or take a look at the book in the sources.

Sources:

Abe Martey, IS-IS Network Design Solution, Chapter 10 - page 298 - 342