19 messages in net.nether.puck.cisco-nsp[c-nsp] Source address on BGP peering...
FromSent OnAttachments
PiltrafillaJan 14, 2005 8:13 am 
Mark TinkaJan 14, 2005 8:46 am 
McCallum, RobertJan 14, 2005 9:00 am 
Daniel GinsburgJan 14, 2005 9:04 am 
Erdem SenerJan 14, 2005 9:09 am 
Marko MilivojevicJan 14, 2005 9:17 am 
Mark TinkaJan 14, 2005 9:19 am 
Rick CosseyJan 14, 2005 9:52 am 
Jared MauchJan 14, 2005 10:02 am 
Stephen J. WilcoxJan 14, 2005 10:34 am 
PiltrafillaJan 17, 2005 11:27 am 
Brian FeenyJan 17, 2005 11:37 am 
PiltrafillaJan 17, 2005 6:59 pm 
Brian FeenyJan 17, 2005 7:18 pm 
Michael K. SmithJan 17, 2005 10:30 pm 
PiltrafillaJan 18, 2005 3:33 am 
PiltrafillaJan 18, 2005 4:49 am 
Michael K. SmithJan 18, 2005 11:52 am 
PiltrafillaJan 24, 2005 8:01 am 
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Subject:[c-nsp] Source address on BGP peering set upActions...
From:McCallum, Robert (robe@thus.net)
Date:Jan 14, 2005 9:00:50 am
List:net.nether.puck.cisco-nsp

hmmmmm isnt that the bgp router-id? I though bgp like any other protocol would take the outgoing interface.

Robert McCallum

-----Original Message----- From: Mark Tinka [mailto:mti@africaonline.co.sz] Sent: 14 January 2005 13:46 To: cisc@puck.nether.net; Piltrafilla Subject: Re: [c-nsp] Source address on BGP peering set up

On Friday 14 January 2005 15:14, Piltrafilla wrote:

Hi people,

Hello.

Anyone knows how BGP on a Cisco router choose source IP address for peering establishment if no "update-source" command is applied to neighbor? Is it only the primary IP address on the closest interface to neighbor?

Without manually specifying your source interface, BGP will find and use the Loopback interface with the highest IP address. Failing that, it will take the next highest IP address configured on the router (regardless of interface).

This can become a problem, especially if you keep adding/removing IP addresses on your router (customers, new routers, new segments, e.t.c.), hence the elegance of 'update-source'.