Re: OSPF ADV Router is not-reachable

Hey

There are few reasons in OSPF that you can state when u see ADV router is
no reachable.

1. ur forwarding address ( present in TYpe 5 or Type 7 ) may be reachable
via a n external route.

2. Network Type mismatch

3. One side is a Unnumbered link and another is a numbered link

4. Wrong subnet on Point to Point links ( It can still form neighborship
even though they r in different subnets as the rule is relaxed in Point to
Point links )

So in ur case, lets see that u r reloading or doing a switchover or
restarting the ospf process on R3 would surely kill the OSPF session with
ur peer. So ultimately u should not see any OSPF neighbor

Are u running any NSF ( Graceful Restart ) with ur neighbor. So for
example when u enable this, then may be ur neighbor may hold down the
routes in FIB and mark the entries as stale and then wait for the Stale
timer to expire to flush the routes from FIB.

If u enable NSR ( Non Stop Routing ) , then Grace LSAs will be sent to the
neighbor when it comes back again to ensure that the database is in syn
after the reload.

Which router are u using and did u check the Routers Docs or how they have
implemented it

Ideally when u shut the link, the ISM ( interface state manager ) will
inform its clients ie OSPF to shut the peer on this interface and
ultimately its flushes the routes for that peer.

I am still wondering is there any way that it will retain the route and
then gives this message "ADV is not reachable"

Can u verify it once more and let me know

On Thu, Dec 13, 2012 at 5:25 PM, ccie99999 <ccie99999_at_gmail.com> wrote:

> why by design it's not?
>

-- 
Regards
Hemanth Raj
CCIE#28593 (R&S)
Blogs and organic groups at http://www.ccie.net