[76970] in North American Network Operators' Group
RE: IBGP Question --- Router Reflector or iBGP Mesh
daemon@ATHENA.MIT.EDU (Erik Haagsman)
Fri Jan 7 19:33:34 2005
From: Erik Haagsman <erik@we-dare.net>
Reply-To: erik@we-dare.net
To: rocrowe@cisco.com
Cc: "'Erik Sundberg'" <sunder@appscorp.net>, nanog@merit.edu
In-Reply-To: <200501072320.j07NKXe13438@rooster.cisco.com>
Date: Sat, 08 Jan 2005 01:30:21 +0100
Errors-To: owner-nanog-outgoing@merit.edu
On Sat, 2005-01-08 at 00:20, Robert Crowe wrote:
> Yes, an iBGP session is possible between A & C. Route Reflectors
> main purpose was to reduce the iBGP full mesh requirement, thus
> providing for BGP scalability. If you only have 3 BGP speakers then
> there is no need, unless you are expecting BGP speaker growth. I
> would address the lack of redundancy for your BGP sessions.
Correct, route reflector's main advantage is scalability and if you're
thinking to evolve into a larger network with dedicated access and core
routers, route reflectors are a far better option than full mesh, though
perhaps not from the start.
Redundancy is a good point, since in the route reflector diagram you
have a single route reflector with single sessions to your edges. If
iBGP link A-B goes down, the rest of your network looses 1 transit ISP
and customer 1 is cut off from the rest of your network, basically
leaving him with a default route out to ISP A and the rest of your
network having to rely on transit to reach your own customer. Also
depends on the actual physical paths to the customer ofcourse
(redundant?), but seems a bit risky, while customer 2 is looking a lot
safer.
Cheers,
Erik
--
---
Erik Haagsman
Network Architect
We Dare BV
tel: +31.10.7507008
fax: +31.10.7507005
http://www.we-dare.nl
