From: Schulz, Dave (DSchulz@dpsciences.com)
Date: Mon Apr 03 2006 - 15:43:56 GMT-3
Michael -
If you are a partial mesh with R2 as your hub, and you need to have a DR
elected, then you must designate your hub as the DR, with none of the
spokes as a BDR. That is because, you will never want a spoke to be
elected as a DR. So, we have to understand "why?". And, what does the
DR do? Remember, the DR is responsible for the sending of all LSAs in
the NBMA and broadcast environments. So, the R1 will never get the LSAs
from R3 (if R3 is elected as DR), and vice versa (not a good thing), and
routing not complete.
You could, however, add a DLCI between R1 and R3...and now, you have a
full mesh....both neighbor relationships are formed and both the
broadcast and non-broadcast types should work.
HTH.
Dave Schulz,
Email: dschulz@dpsciences.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Michael
Sent: Monday, April 03, 2006 1:24 AM
To: catwater@aussiemail.com.au
Cc: ccielab@groupstudy.com
Subject: RE: OSPF - Hub & Spoke - Point-to-Multipoint
Ok, but doesn't Cisco documentation say differently? I'm really
confused
about this for some reason I don't understand yet. I do understand
about
TTL = 1. So with any configuration then R1 and R3 will never be
neighbors
in OSPF? Only neighbors are spoke(s) & hub then?
The optional OSPF interface settings only allow DR election & timer
settings?
So when would you logically use Cisco default NBMA OSPF interface rather
than P-M?
-----Original Message-----
From: Charlie Atwater [mailto:catwater@AUSSIEMAIL.COM.AU]
Sent: Sunday, April 02, 2006 11:15 PM
To: mamiller2@comcast.net
Cc: ccielab@groupstudy.com
Subject: Re: OSPF - Hub & Spoke - Point-to-Multipoint
Michael I believe this is because R1 and R2 are neighbors as are R2 and
R3.
But R1 and R3 are not actually neighbors.
CAT
--- mamiller2@comcast.net wrote:
From: "Michael" <mamiller2@comcast.net>
To: "ccielab" <ccielab@groupstudy.com>
Subject: OSPF - Hub & Spoke - Point-to-Multipoint
Date: Sun, 2 Apr 2006 21:43:09 -0600
Hi All,
I am trying to understand some information about FR Point-to-Multipoint
network interfaces in a Hub and Spoke architecture. I think I just
figured
it out but I still would like to hear comments.
R1 (Spoke) <-> R2 (Hub) <-> R3 (Spoke)
All three routers are physically connected to a IOS router and
configured
using routed PVC's. Is it because of the routed pvc's that I do not see
"IP
OSPF Neighbors" of R3 in R1?
I am using physical (multipoint) interfaces with frame maps.
Is it true that switched pvc's in my IOS router would react differently?
Thanks,
Michael
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