Re: [nsp] BGP routing questions

From: Robert E. Seastrom (rs@seastrom.com)
Date: Sun Oct 03 1999 - 16:51:10 EDT


Rafi Sadowsky <rafi@noc.ilan.net.il> writes:

> 1) to set the BGP id to Loopback0 IP for neighbor 10.1.1.1
>
> neighbor 10.1.1.1 update-source Loopback0

No, that's not what update-source does; update-source sets the origin
of the session for ebgp multihop and does not affect the router-id
(router-id is constant among all bgp sessions and is not
neighbor-by-neighbor configurable AFAIK). For the official
documentation, see:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/np1_r/1rprt1/1rbgp.htm#xtocid17930311

> 2) your setting "NEXT_HOP is always this router" -may alter the
> defaults you obviously have "neighbor 192.41.177.87 next-hop-self"
> (*not* the default) in your BGP config I hope you know why ( non
> fully-meshed FR subnet or whatever )

It is generally a good idea to set next-hop-self on eBGP sessions,
particularly across shared-media public exchange points (the ip
address used in the example is a clue here). The reason why is left
as an exercise to the reader.

                                        ---Rob



This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:12:06 EDT