IS-IS Multi-Area

Multi-Area Integrated IS-IS

Topology

 

Objectives

• Configure multi-area IS-IS
• Review configuration of IS-IS level 1 and 2
• Verify IS-IS adjacencies and view IS-IS database
• Review IS-IS domain authentication
• Verify intra-area IS-IS operation

Verify IS-IS operation

I'm just going to verify the configuration on the routers by using the following commands;

Verify IS-IS Multi-Area Operation

R3 will only keep a link state database for IS-IS level 2.





The fast ethernet interface on R1 confirms that it is a Level 1 and 2 router;

Verify IS-IS Intra-Area Operation

If we check R2s routing table we can see that it only has level 1 routers and that the gateway of last resort has been set. A level 1 router can learn this from a neighbouring Level 1-2 router.



By checking the IS-IS database you can see R1 has an attached bit which indicates it is also a level 2 router and can reach other areas.

Complete