From: Lachlan Kidd (lkidd@xxxxxxxxxxxxxxxxxxx)
Date: Wed Apr 04 2001 - 20:20:54 GMT-3
Hi Guy,
As I understand it, point-to-multipoint creates multiple point-to-point
links between the hub and spokes. Now I may have this next bit
wrong.....because the links are point to point, the concept of broadcasting
becomes redundant. The router assumes that if you stuff data down one end of
a p-t-p link it will pop out the other end. Futher to this, in a p-t-mp
environment, OSPF will inject a /32 route to each of the spokes interfaces
into the route table. This ensures spoke to spoke connectivity.
If I've got this majorly wrong can someone please correct me.
Thanks, Regards,
Lachlan
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Guy Farber
Sent: Thursday, 5 April 2001 7:16:AM
To: Daniel C. Young; ccielab@groupstudy.com
Subject: Re: OSPF over NBMA
Thanks. What does multipoint do to solve the problem?
----- Original Message -----
From: "Daniel C. Young" <danyoung99@mediaone.net>
To: "'Guy Farber'" <gfarber@cisco.com>; <ccielab@groupstudy.com>
Sent: Wednesday, April 04, 2001 10:33 PM
Subject: RE: OSPF over NBMA
> Also, guy. If your spoke was using a subinterface, you would not see
> neighbors unless you typed 'ip ospf network point-to-multipoint'. Of
course,
> 'ip ospf network broadcast' would work as well.
>
> The point is, as Pamela explained, OSPF treats FR (by default) as a
> nonbroadcast network, which means that the multicasts needed to become
> neighbors (224.0.0.5) are not sent.
>
> Hope this clears it up.
>
> Daniel Young
> Sr. Network Engineer
> Internet Data Center
> SBC Service Inc. - ITO
>
> (949) 221-1928 Office
> (714) 350-8945 Cell
> ICQ# 109846891
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> Guy Farber
> Sent: Wednesday, April 04, 2001 2:57 AM
> To: ccielab@groupstudy.com
> Subject: OSPF over NBMA
>
>
> Guys,
>
> I have a very simple FR network. One router functions at the FR switch and
2
> others have a pvc between them. When I run OSPF over the FR link without
> changing any OSPF interface parameters and using in-arp, hellos are not
> being sent from the routers. If I change the interface type to broadcast,
> they start exchanging hellos and finally build an adjacency. Now for the
> interesting part, if I put a neighbor statement on one of them they start
> exchanging hellos and become neighbors. If I remove the neighbor statement
> it stays the same.
>
> I'm using 2621 and 3640 with ver 12.1(4)
>
> What am I missing here?
>
> -------------------------------------------------
> Guy Farber
> Systems Engineer
>
> Tel: +972 (9) 970-0363
> Fax: +972 (9) 970-0019
> GSM: +972 (54) 975-363
> Email: gfarber@cisco.com
>
> Cisco Systems Israel
> 85 Medinat Hayehudim St.
> 46766 Herzliya
> ISRAEL
> -------------------------------------------------
> "Programming today is a race between software engineers striving to build
> bigger and better idiot-proof programs, and the Universe trying to produce
> bigger and better idiots. So far, the Universe is winning."
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