From: Jonathan Hays (nomad@gfoyle.org)
Date: Fri Dec 19 2003 - 10:48:39 GMT-3
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
This archive was generated by hypermail 2.1.4 : Sat Jan 03 2004 - 08:25:43 GMT-3