From: Collins Bill (parfour_on_9@xxxxxxxxxxx)
Date: Sun Mar 12 2000 - 22:44:53 GMT-3
You would really want to include the link between R1 and R4 in Area 0.
Otherwise, if the link were an ISDN link used for backup or DDR, then you
would indeed use 2 virtual-link statements. As long as the ISDN link was
down, there would only be 1 virtual-link up at that time. Otherwise, the
second virtual-link would come up when the primary link (in this case FR)
went down. I have never seen a situation like this however, I am open to
being corrected.
Bob
>From: Ben_J_Durand@tivoli.com
>Reply-To: Ben_J_Durand@tivoli.com
>To: ccielab@groupstudy.com
>Subject: Can virtual link areas be chained?
>Date: Sun, 12 Mar 2000 14:10:00 -0500
>
>Hi guys,
>
>I ran into an interesting problem. The bottom line question is: Can ospf
>virtual links be chained? i.e traverse more than one transit area?
>
>Here is the scenario:
>
>
> A2 A3
> /R1------R2------R3
> / |
>A0 |
>FR | A4
> \ |
> \R4
>
>
>In this case, I've declared A2 as transit (virtual link) on R1 and R2 to
>give R3
>OSPF updates. Problem is, if R1 loses its connection to the frame cloud,
>it
>loses its connection to area 0. This means that packets from Area 3 would
>have
>to go through area 4 in order to get routed, which violates the rules of
>OSPF.
>Can A4 between R1 and R4 be declared as a second virtual link, chained to
>the
>one declared between R1 and R2? If so, how do the configs look? does an
>"area 4
>virtual-link..." need to be added to R3?
>
>This is obviously not the best design in the world, but if you had to work
>with
>it, what would you do?
>
>- Ben
>
>
>
>
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