nanog mailing list archives
Re: IBGP Question --- Router Reflector or iBGP Mesh
From: Iljitsch van Beijnum <iljitsch () muada com>
Date: Wed, 12 Jan 2005 12:20:22 +0100
On 12-jan-05, at 9:06, Alexei Roudnev wrote:
Are you sure? RR should just distribute routes.
RR do not make any route decisions, and (btw) iBGP do not make route decisions - they are mostly based on IGP routing.
Route reflectors only propagate their idea of the best route for a destination. If this decision is based on eBGP-learned information such as the AS path this doesn't matter because all routers in the AS would make the same decision anyway, but if the IGP metric comes into play (which invariably happens in large networks) then all the reflector clients only see the route that is best based on the IGP metrics the reflector sees.
(Obviously the IGP metric will be different at the client, but the client doesn't see the other routes, so it can't make a different decision. The real fun starts when the next (intra-AS) hop isn't a reflector client and the packet now takes a different path than the reflector client thought it would take.)
Current thread:
- IBGP Question --- Router Reflector or iBGP Mesh Erik Sundberg (Jan 07)
- RE: IBGP Question --- Router Reflector or iBGP Mesh Robert Crowe (Jan 07)
- RE: IBGP Question --- Router Reflector or iBGP Mesh Erik Haagsman (Jan 07)
- RE: IBGP Question --- Router Reflector or iBGP Mesh Eric Kagan (Jan 10)
- RE: IBGP Question --- Router Reflector or iBGP Mesh Erik Haagsman (Jan 11)
- Re: IBGP Question --- Router Reflector or iBGP Mesh Philip Smith (Jan 11)
- Re: IBGP Question --- Router Reflector or iBGP Mesh Daniel Roesen (Jan 11)
- Re: IBGP Question --- Router Reflector or iBGP Mesh Erik Haagsman (Jan 11)
- Re: IBGP Question --- Router Reflector or iBGP Mesh Alexei Roudnev (Jan 12)
- Re: IBGP Question --- Router Reflector or iBGP Mesh Iljitsch van Beijnum (Jan 12)
- Re: IBGP Question --- Router Reflector or iBGP Mesh Erik Haagsman (Jan 12)
- Re: IBGP Question --- Router Reflector or iBGP Mesh Alexei Roudnev (Jan 12)
- Re: IBGP Question --- Router Reflector or iBGP Mesh David Barak (Jan 12)
- Re: IBGP Question --- Router Reflector or iBGP Mesh Alexei Roudnev (Jan 13)
- RE: IBGP Question --- Router Reflector or iBGP Mesh Erik Haagsman (Jan 07)
- RE: IBGP Question --- Router Reflector or iBGP Mesh Robert Crowe (Jan 07)
- Re: IBGP Question --- Router Reflector or iBGP Mesh Iljitsch van Beijnum (Jan 11)