distributing routes from external eigrp AS to internal eigrp AS

rperera · ‎12-22-2008

We are running EIGRP on the external and internal networks using 2 different AS numbers, 465 for external and 1 for internal. The external network has 2 links to carrier network and the BGP routing is distributed to the eigrp 465 and is working as expected. The problem we are having is trying to pass the specific routes from 465 to internal AS 1. The two sites are linked via 2 ASA clusters to the internal network. How do you pass the link failure of one site to the internal network so traffic will automatically reroute to the other site?

Giuseppe Larosa · ‎12-22-2008

Hello Raphael,

I see two ways:

or you make ASA devices to talk EIGRP too

http://www.cisco.com/en/US/docs/security/asa/asa80/configuration/guide/ip.html#wp1092871

or you use two point-to-point GRE tunnels and you run EIGRP over the tunnel to cross the ASA devices

Hope to help

Giuseppe

rperera · ‎12-22-2008

Giuseppe,

Thanks for the reply. So do we specify both AS 465 and 1 on the same router? I thought each router can only belong to a single AS!

Giuseppe Larosa · ‎12-22-2008

Hello Rafael,

the limitation of a router in a single AS is true only for BGP AS number

A router can run multiple instances of EIGRP using each a different EIGRP AS numbere with or without redistribution.

However, on a network link to build an EIGRP adjacency the AS number must be the same.

From this derives that without redistribution on a router running both EIGRP processes the two cannot communicate/exchange routing information.

Hope to help

Giuseppe