From: Voytek Mielczarek (Voytek.Mielczarek@xxxxxxxxxx)
Date: Sat Aug 18 2001 - 22:58:41 GMT-3
This has been discussed here many times, but there is always a new question to
an old scenario... Lets say we have a network as below (based on Hutnik "CCIE L
ab Practice Kit" p.234).
All shown links are serial or ethernet, except R1-R5 which is ISDN backup link
that is activated when link R4-R5 goes down.
R1 ---- R2
|\ /
| \ / area3
| \ /
| \/
| R3
| | area 0
| |
| R4
| | area 1
area2 | |
----R5-----R6 IGRP
|
area2 ---
Q1 is to summarise interarea routes from area 3 to area 0, so you apply "area 3
range x.x.x.x y.y.y.y"
and a couple of routes from R4 are gone and a summary route added, DONE.
Q2 is to provide connectivity to area 2, so you create a virtual link across ar
ea 1, DONE.
Q3 configure ISDN to backup the serial R4-R5 link, so another virtual link must
be configured between R1 and R3 in order to provide connectivity from area 2 t
o area 0 via ISDN when activated, DONE.
NOW, when a virtual link in configured between R1 and R3, internal routes from
area 3 appear again on router R4 (because we extended area 0 to R1), so we have
to go back to Q1 to fix it!
And the fix that appears to be working is configuring exactly the same statemen
t on R1, as we used on router R3 which was "area 3 range x.x.x.x y.y.y.y". And
that removed again the interarea routes from R4 leaving only the summary route
as required in Q1.
Any comments? Is that the right solution?
Regards, Voytek
**Please read:http://www.groupstudy.com/list/posting.html
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 10:31:53 GMT-3