From: Paul Young (tsungdapaulyoung@xxxxxxxxx)
Date: Sun Sep 16 2001 - 23:43:05 GMT-3
Hi Group:
Some additional debug I'd captured (see below)
which shows BGP routes are withdrawn from its 2
neighbors 172.16.4.3 and 172.16.14.1 just shortly
after it has installed the BGP routes. I'm double
checking both next-hop & reachability issues. Don't
think it's next-hop though since I did enter
next-hop-self from all BGP border routers R1 & R3.
I've tried both using OSPF as well as route-reflector
method to provide reachability, so far the results are
the same (all routes first initially get installed on
R4, then removed or withdrawn by neighbor routers
shortly after)
00:25:58: BGP: 172.16.4.3 send message type 4, length
(incl. header) 19
00:25:58: BGP(0): 172.16.4.3 rcv UPDATE about
2.1.1.0/24 -- withdrawn
00:25:58: BGP(0): 172.16.4.3 rcv UPDATE about
7.1.1.0/24 -- withdrawn
00:25:58: BGP(0): 172.16.4.3 rcv UPDATE about
172.16.123.0/24 -- withdrawn
00:25:58: BGP: 172.16.4.3 rcv message type 4, length
(excl. header) 0
00:25:58: BGP(0): 172.16.14.1 rcv UPDATE about
5.1.1.0/24 -- withdrawn
00:25:58: BGP(0): 172.16.14.1 rcv UPDATE about
7.2.2.0/24 -- withdrawn
00:25:58: BGP(0): 172.16.14.1 rcv UPDATE about
172.16.35.0/24 -- withdrawn
r4#
00:26:00: BGP: 172.16.14.1 send message type 4, length
(incl. header) 19
00:26:00: BGP: 172.16.14.1 rcv message type 4, length
(excl. header) 0
r4#
--- Nigel Taylor <nigel_taylor@hotmail.com> wrote:
> From: "Nigel Taylor" <nigel_taylor@hotmail.com>
> To: "Paul Young" <tsungdapaulyoung@yahoo.com>,
> <ccielab@groupstudy.com>
> Subject: Re: BGP route withdraw question ECP1 lab
> scenario
> Date: Sun, 16 Sep 2001 21:41:24 -0400
> Reply-to: "Nigel Taylor" <nigel_taylor@hotmail.com>
>
> Paul,
> Just from what you're describing it's likely
> possible that the
> next-hop
> is inaccessible. This of course would result from
> a flapping interface or
> this
> would be typical in a NBMA enviroment where all you
> devices wasn't fully
> meshed. Look to your layer2 configurations and the
> your layer3 for
> reachability issues... Remember BGP does use it's
> updates to withdraw route
> information which no longer is valid based on the
> use of BGP's NLRI
> information.
>
> HTH
>
> Nigel
>
>
> ----- Original Message -----
> From: "Paul Young" <tsungdapaulyoung@yahoo.com>
> To: <ccielab@groupstudy.com>
> Sent: Sunday, September 16, 2001 9:15 PM
> Subject: BGP route withdraw question ECP1 lab
> scenario
>
>
> > Does anyone know what may be the cause of correct
> BGP
> > routes being installed initially, then some of the
> BGP
> > routes (BGP routes with dual paths) got withdrawn
> by
> > its neighbors for some reason. Trying to
> troubleshoot
> > this problem.
> > Any ideas, inputs appreciated.
> >
> > Using ECP1's Configuring BGP (Additional
> exercise).
> >
> >
> >
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 10:32:19 GMT-3