From: Jonathan Hays (nomad@gfoyle.org)
Date: Fri Dec 19 2003 - 15:42:31 GMT-3
Marko,
See Brian McGahan's response to this thread I believe he has the correct
answer.
If you are running OSPF over hub and spoke frame-relay you cannot have a
BDR. If one of the spokes becomes BDR it won't have direct connectivity
to the rest of the network, like the hub does. Try it in your lab and
see . . .
The best practice is this:
Hub -> (leave at default)
Spoke 1 -> pri 0
Spoke 2 -> pri 0
Jonathan
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Marko Berend
Sent: Friday, December 19, 2003 9:10 AM
To: ccielab@groupstudy.com
Subject: RE: OSPF ID of 0.0.0.0
Hi
I tried and my routers also ignore router-id 0.0.0.0
But you can make the hub a DR and one of the spokes BDR by modifying
priority since it is the first tie breaker (default priority is 1).
Hub -> priority 2
Spoke 1 -> pri 1
Spoke 2 -> pri 0
MB
-----Original Message-----
From: Jonathan Hays [mailto:nomad@gfoyle.org]
Sent: 19. prosinac 2003 14:49
To: ccielab@groupstudy.com
Subject: OSPF ID of 0.0.0.0
I recently saw a practice lab scenario with 3 OSPF area 0 routers
connected via hub and spoke frame-relay (no subinterfaces). The
requirement asked that the DR and BDR have an "ID of 0.0.0.0" which
puzzled me. Unfortunately the solution was missing so I am asking for
some help on figuring this one out.
First, it seems to me that in a 3-router hub-and-spoke frame-relay that
a BDR is not possible, since neither of the spokes can function as a
DR/BDR. Normally you just configure "ip ospf priority 0" on the spokes
and the FR hub router becomes your DR. Maybe the requirement for a BDR
was a typo? Or maybe the DR was required and the BDR was optional? (But
it does say DR *and* BDR.)
Second, I thought of configuring the OSPF router ID of the F-R hub with
0.0.0.0 (if indeed the router ID is the "ID" they were referring to) but
I tried it and OSPF does not like that. It just ignores the "router-id
0.0.0.0" config and uses the highest loopback. Are they referring to
some other ID? LSA ID?
Lastly, although there were no constraints against changing network
type, since the question specifies DR/BDR then you cannot use OSPF
point-to-point or point-to-multipoint since you have to have a DR (and
maybe a BDR, too).
Any ideas on this one?
Thanks in advance,
Jonathan
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