[23035] in North American Network Operators' Group
RE: Multiple BGP sessions between the same router pairs at IXPs
daemon@ATHENA.MIT.EDU (Chad Skidmore)
Wed Feb 10 23:38:09 1999
From: Chad Skidmore <cskidmore@winstar.com>
Reply-To: amb@gxn.net
To: "'Alex Bligh '" <amb@gxn.net>, "'nanog@merit.edu '" <nanog@merit.edu>
Date: Wed, 10 Feb 1999 20:25:08 -0800
Yes, you are correct. In a NAP configuration that is changing this probably
would be difficult to avoid.
-----Original Message-----
From: Alex Bligh
To: nanog@merit.edu
Cc: amb@gxn.net
Sent: 2/10/99 12:37 AM
Subject: Multiple BGP sessions between the same router pairs at IXPs
Anyone feel like sanity checking this for me:
As far as I know, if you have this config
RTRA BGP ID 4.4.4.4 ASN 4
2.2.2.4 / \ 3.3.3.4
2.2.2.0/24 | | 3.3.3.0/24
2.2.2.5 \ / 3.3.3.5
RTRB BGP ID 5.5.5.5 ASN 5
and you configure on router A
router bgp 4
neighbor 2.2.2.5 remote-as 5
nieghbor 3.3.3.5 remote-as 5
and on router B
router bgp 5
neighbor 2.2.2.4 remote-as 4
nieghbor 3.3.3.4 remote-as 4
then only one peering session will come up, as routers only
support one BGP session with any given router ID.
We hit this problem when renumbering the LINX, I think, in that
you have to make sure you take down old sessions to get new
sessions to work.
This would also affect people who set up new peerings over
the ATM MAE's, who also have existing peerings on the FDDI
fabric between the same routers, right?
--
Alex Bligh
GX Networks (formerly Xara Networks)
