How to configure IS-IS for a Cisco Router

IS-IS known by many friends who are familiar with Cisco routers, but for new users, they do not know how to set IS-IS for Cisco routers, this document describes how to set IS-IS for a Cisco router from an experimental perspective. The following are the basic settings for a Cisco router to use the IS-IS Route IP Address:

1. determine the area where the vro IS located, and activate the IS-IS interface on the vro.

To activate IS-IS on a vro, run the following command:

Router (config) # router isis

2. Set NET with the following command:

Router (config-router) # net 00. 0001.3090.6756.00

3. Activate IS-IS on the corresponding interface. The command IS as follows:

Router (config-if) # ip router isis

4. Set the vro type, such as Level 1, Level 2, or Level 1/Level 2. By default, the Cisco vro type is Level 1/Level 2. The command is as follows:

Router (config-router) # is-type level-1

Router

Interface Ethernet 0

Ip address 10.1.3.1 255.255.255.0

Ip router isis (activating IS-IS on the interface so that the IP subnet of this interface can be published)

Interface serial 0

Ip address 10.1.4.1 255.255.255.0

Ip router isis

Router isis

Net 49.0001.0000.0000.000a.00 (set NET, 49 to area id, 0001.0000000a to system id)

Is-type level-2-only vro type is Level 2

Router B

Interface Ethernet 0

Ip address 10.1.5.2 255.255.255.0

Ip router isis

Interface Ethernet 1

Ip address 10.1.6.2 255.255.255.0

Ip router isis

Interface serial 0

Ip address 10.1.4.2 255.255.255.0

Ip router isis

Router isis

Net 49.0001.0000.0000.000b.00

Is-type level-2-only

Router C

Interface Ethernet 0

Ip address 10.1.7.3 255.255.255.0

Ip router isis

Interface Ethernet 1

Ip address 10.1.6.3 255.255.255.0

Ip router isis

Router isis

Net 49.0001.0000.0000.000c.00

Is-type level-2-only

You can use the following command to monitor the IS-IS status:

1. Observe the adjacent State.

Router # show clns is-neigbors

2. Observe the database connection status.

Router # show isis database

3. list all SPF operations recently performed by the vro.

Router # show isis spf-log

4. List the events that trigger the SPF algorithm on the router.

Router # debug isis spf-events