Just to add to Alan's 'stability' bullet, one other thing to bear in mind would be convergence time of routes on any given box in a reflected 'region' during an event if said multi-use route-reflector is attempting to do other useful things, such as shovel packets, at the same time as converge routes with all it's clients. IME, you will need to decide on the importance to you of reconverging during/following a failure vs route selection during normal operation. Typically the latter is way important, obviously but it can be mitigated somewhat by careful placement, topology-wise, of ones dedictated route-reflector. One other small point (and a potential flame attractor at that), route selection in a reflected environment in and of itself can (and in a large network, usually does) result in some levels of suboptimal route selection. YMWV depending on your topology. I would agree that 40 is a very nice number for a multi-use RR and that, given a healthy quantity of memory in a dedicated RR, can probably be doubled without significant additional convergance time. -Steve * Alan Hannan <alan@routingloop.com> [010501 21:40]:
Something like 40 iBGP peering sessions should be doable in most circumstances. Mileage will vary significantly as a function of:
physical topology RR Topology policy (routes, dampening, etc..) stability .. and other things
Adding a tertiary box such as a 7206 or some such box as a BGP route reflector may work fine -- but can give rise to improper routing information. (esp. wrt route selection)
In general, one wants the routing information (control plane) to follow the forwarding path (data plane) as closely as possible.
-alan
Thus spake James DeMong (James.DeMong@telus.com) on or about Tue, May 01, 2001 at 01:31:27PM -0600:
I have a GSR 12008 that is acting as a route reflector and core router. What is the practical maximum (from an operational standpoint) number of clients it can support? (My Cisco sources tell me that the maximum technically possible is large and does not significantly impact the operation the forwarding of the GSR.)
In terms of manageability and simplicity, is it more favourable to have a separate box (e.g. 7206 VXR) handle the route reflector job?
Thanks in advance for your thoughts.
James __ James DeMong Network Design Specialist TELUS Advanced Communications Phone: (403) 503-3718 Email: James.DeMong@telus.com
-- -aToM http://the.soulclub.org