On Tue, 2009-09-08 at 16:05 -0700, Tony wrote: > I'm curious, I thought setting the RD the same on each PE router > (obviously per VPN) was the way to do things ? ... > When do/should you set the RD to be different ? I'm guessing it's > going to be for larger installations and to allow more customisation > or something ?
The main difference (AFAIK) is that in a route reflector setup, your RR will reflect all the different routes as long as all the PEs use different RDs. This in turn means that each RR client (PE) will need more memory to hold all possible prefixes, but on the other hand they will be able to use one of the alternative paths immediately upon discovering that the current best path is invalid, e.g. by the BGP next hop for the current best path disappearing from the IGP. With the same RD on all PEs your route reflector will only reflect the current best path. When this invalidates you have to wait for the RR to select a new best path and update the RR clients. In the mean time traffic is black-holed. So basically: Faster convergence in a route reflector setup. -- Peter _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
