From: Tony Olzak (aolzak@xxxxxxxxxxxxxxxxxxx)
Date: Fri Dec 01 2000 - 12:29:55 GMT-3
Chuck,
The virtual link would not reconverge because of how it is configured. It
needs to use Area 1 as a transit area and terminate on a specific routed ID.
It wouldn't be able to go through other routers in your setup because it
would have to either terminate on a different RID (not acceptable) or
transit area 0. Best thing would be just to have two virtual links (better
yet, no virtual links at all!).
And you are right, the RID doesn't change at all without rebooting the
router. But, what do most techs do when a link is having problems? Reboot
the routers. Now your RID will change.
Tony
----- Original Message -----
From: "Chuck Larrieu" <chuck@cl.cncdsl.com>
To: "Louie Belt" <louieb@netmatter.com>; "'CCIE_Lab Groupstudy List'"
<ccielab@groupstudy.com>; <cisco@groupstudy.com>
Sent: Friday, December 01, 2000 1:39 AM
Subject: RE: OSPF Lab - DR behaviour with loopbacks WAS: RE: question about
loopback interfaces
> I'm not so sure that this would happen as you describe.
>
> Assuming the RID is based on a non-OSPF interface address, and assuming
that
> the OSPF process initialized, and that the OSPF domain reached stability,
I
> don't believe the flapping of the non-OSPF interface, or even the
> disappearance of the non-OSPF interface, would have any effect on the OSPF
> side of things.
>
> I am certain that once the RID is determined, it is permanently installed
> into the OSPF process, and it is hell to remove it. I did some experiments
> reported recently in another thread in answer to Howard's problem. I and I
> am sure I have seen the question elsewhere as well.
> Once the RID has been determined by the OSPF process, bringing up another
> interface with a higher IP address, or changing the IP address of the
> interface that is the basis of the RID, has no effect, until such time as
> one reloads the router.
>
> Reloading is the only way I have found to change the RID. Clear IP OSPF
> Process does not do so. Re-addressing each and every interface, and
removing
> old network statements and installing new network statements does not do
so.
>
> This does bring to question the exact nature of a virtual link. In a
> situation where the topology permits, will a virtual link re-establish
> itself if it's first path interface fails?
>
> EG:
>
> RID1.1.1.1
> RouterA------Area_0-----------RouterB
> | |
> | |
> RouterC------Area_1----------RouterD
> |
> |
> RouterE(Area_2)
> RID 2.2.2.2
>
> The virtual link on router C is defined as area 1 virtual-link 1.1.1.1
> The virtual link on router A is defined as area 1 virtual-link 2.2.2.2
>
> If the link between C and A goes down, will the virtual link remain
alive,
> because there is a path to router A via routers D and B?
> Without trying another Q&D, I am surmising the answer is "no" because the
> virtual link termination points must be on an ABR, and RouterA is not an
ABR
> with respect to RouterD
>
> Damn, yet another experiment.....
>
> Chuck
>
>
>
>
>
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