From: Paul Borghese (paul98@xxxxxxxxxxx)
Date: Wed Mar 06 2002 - 15:34:38 GMT-3
Hi,
I have created a practice scenario using the following setup (OSPF protocol):
R1 is connected to R2 and the connection is in Area 0. R2 is connected to R5
in Area 100. R5 has a backup ISDN link to R1. I made this backup Link area
101 and created a virtual link through area 101 to connect Area 100 in case
the connection to R2 ever went down. R1 has a route (172.16.1.0) which is in
Area 0.
The problem I am having is R5 always prefers to use the BRI interface to get
to 172.16.1.0 instead of using the connection to R2. I even set the cost of
the BRI interface to be 10x that of the R2 connection. Here is the results on
R5:
With the ISDN line active:
172.16.0.0/24 is subnetted, 1 subnets
O 172.16.1.0 [110/10010] via 190.27.1.66, 00:52:04, Dialer0
With the ISDN in Shutdown mode:
172.16.0.0/24 is subnetted, 1 subnets
O IA 172.16.1.0 [110/943] via 190.27.1.33, 00:00:03, Serial4
Notice with the ISDN active, the router prefers to use the Dialer interface
even though the metric is 10010 versus the Serial 4 interface with a metric of
943! I believe this is because the route learned via the Dialer0 interface is
an interior route and the route learned via the S4 interface is an InterArea
route.
So is there any way to get R5 to prefer the S4 route with the Dialer interface
active? Of course one way to fix this would be to make the ISDN line area
100 and dump the Virtual Link. But I am wondering if there is a way to do it
using the typology I created.
Paul Borghese
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