Sent this yesterday but it doesn't seem to have come through.
In response to some of the other comments on this thread, an MTU mismatch
will definitely cause the OSPF neighbours to not be neighbourly :-) I
have come across this when upgrading a frame relay service from standard
serial (MTU 1500) to an HSSI (default MTU 4470 I think - not 1500,
anyway).
JMcL
----- Forwarded by Jenny Mcleod/NSO/CSDA on 16/01/2002 08:34 am -----
Jenny Mcleod
15/01/2002 03:30 pm
To: [EMAIL PROTECTED]
cc:
Subject: RE: Encapsulation Failed [7:31916]
Actually, OSPF neighbour states will become "Full" on point to point
links.
I don't have the time or playpen to double-check the state transitions at
the moment, but a quick check shows "Full" across point to point frame
relay sub-interfaces and also across leased lines.
JMcL
"Kane, Christopher A."
Sent by: [EMAIL PROTECTED]
15/01/2002 02:04 pm
Please respond to "Kane, Christopher A."
To: [EMAIL PROTECTED]
cc:
Subject: RE: Encapsulation Failed [7:31916]
Yes, OSPF sends hellos on Serial interfaces. In point-to-point networks
OSPF's hello is multicast. There is no DR/BDR so it's my understanding
that
it simply becomes a Master/Slave relationship.
Mindful that in OSPF a Neighbor is not the same as an Adjacency. All
routers
become neighbors (assuming all aspects of the Hello protocol are agreed
upon) They only become Adjacent with the respective DR and BDR of the
network in the case of a network on a broadcast medium. I'm pretty sure
you
only see "2-way" as a neighbor state on point-to-point links rather than
seeing "Full" as on a broadcast medium.
I'd need someone else to chime in on point-to-multipoint as I haven't
configured that lately.
Chris
-----Original Message-----
From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]]
Sent: Monday, January 14, 2002 8:40 PM
To: [EMAIL PROTECTED]
Subject: Re: Encapsulation Failed [7:31916]
At 07:57 PM 1/14/02, s vermill wrote:
>Priscilla,
>
>May I ask what led you to believe that bridging was involved as opposed
to
>just assuming that the source address was the Cisco router itself?
Good question. The IBM 6611 does bridging for one thing. The other hint
was
that it was attempting to send an OSPF Hello on a serial interface. Does
OSPF do that? How does it establish adjacency to a neighbor router on a
WAN? On a point-to-point network, I figured it just knew who its neighbor
was.
On a non-broadcast, multiple-access network, such as Frame Relay, you
normally configured the neighbor command.
I've only seen the OSPF multicast Hellos on LANs, (but I can't afford a
WAN
Sniffer anymore! ;-)
Gurus? Help? Thanks.
Priscilla
P.S. Anyone seeing this may be confused because you didn't include the
original message. PLEASE, people, reply with the body of the message in
the
reply. We work in connectionless, stateless mode. How do you expect anyone
to easily connect this to the discussion about a router failing to forward
a packet on a PPP link to an IBM 6611. Hello?????
>Just as an opportunity to learn something.
>
>Regards,
>
>Scott
________________________
Priscilla Oppenheimer
http://www.priscilla.com
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=32064&t=31916
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