A Question about IGP Redistribution and Route Filtering

From: Zhang, George (George.Zhang@xxxxxxxxxxxxx)
Date: Sun Feb 10 2002 - 15:58:16 GMT-3

   
I have a question regarding doing IGP redistribution in the CCIE lab.

When I do IGP mutual redistributions in real world, my favoriate approach is
to put a route-map on the redistribute command to only allow the routes from
the source domain. For example, in the follow scenario,

--192.168.1.1/24--R1---OSPF---R2--IGRP--R3--192.168.100.1/24

OSPF is running between R1 and R2, and IGRP is runing between R2 and R3.
When I do mutual redistribution between OSPF and IGRP on R2, I always do the
following:

R2 Config:

router ospf 1
   red igrp 1 subnet route-map igrp2ospf

router igrp 1
   red ospf 1
   default metric 64 100 255 1 1500

access-list 1 permit 192.168.100.0 0.0.0.255

route-map igrp2ospf permit 10
  match ip address 1

I know that, some time, the route-map filter is redundant. But it should
help in avoiding loops in your network. It always gives me a peace of mind
that I will not get any route feedback. The only drawback might be
performance issue if there is.

In the above mentioned scenario, if split-horizion is turned on in the
interface of R3, then the route-map filter is not needed.

My question: In this case, is the route-map considered extra command in the
CCIE lab?

I don't know if the answer to this question is an violation of NDA. If you
feel so, don't answer it. Otherwise, any answer/comment/input will be
appreciated.

Thanks.

George

This archive was generated by hypermail 2.1.4 : Thu Jun 20 2002 - 13:46:18 GMT-3