From: Jaeheon Yoo (kghost@xxxxxxxxxxxx)
Date: Wed Mar 06 2002 - 19:50:45 GMT-3
Hi, Paul
Why don't you make a virtual link between R2 and R5. What you have observed is
a normal OSPF behavior. OSPF prefers intra-area routes(ISDN link over a virtua
l link) over inter-area routes(via area 100).
I hope this will help you.
Regards,
Jaeheon
----- Original Message -----
From: "Paul Borghese" <pborghese@groupstudy.com>
To: "Bob Sinclair" <bsin@erols.com>
Cc: <ccielab@groupstudy.com>
Sent: Thursday, March 07, 2002 4:52 AM
Subject: Re: Virtual Links and Backup Interfaces in OSPF
> I don't think this will work as both routes are learned via OSPF. The admin
> distance is for selecting which protocol to believe if two different routing
> protocols are advertising the same route.
>
> Am I missing something?
>
> Paul Borghese
>
> ----- Original Message -----
> From: "Bob Sinclair" <bsin@erols.com>
> To: "Paul Borghese" <paul98@prodigy.net>
> Cc: <ccielab@groupstudy.com>
> Sent: Wednesday, March 06, 2002 2:15 PM
> Subject: Re: Virtual Links and Backup Interfaces in OSPF
>
>
> > Just a thought: what if you raised the admin distance for ospf routes
> learned from the router on the other side of the BRI? I have had some
> success doing this with ospf.
> >
> > ----- Original Message -----
> > From: "Paul Borghese" <paul98@prodigy.net>
> > To: <ccielab@groupstudy.com>
> > Sent: Wednesday, March 06, 2002 1:34 PM
> > Subject: Virtual Links and Backup Interfaces in OSPF
> >
> >
> > > 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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