Using multiple RD's is important for convergence when you are using route-reflectors as a route-reflector will only advertise the "best" BGP route to it's clients. If you use the same RD for a VPN across two (Or more) PE's then the route-reflector will see that route as the same and only pick the one it considers the best. If you use unique RD's the route-reflector will not consider the routes the same and will advertise both of them.
Taking this even further, you may also want to investigate the command "maximum-paths ibgp unequal-cost" which can be used to protect against route-reflector failure. For example, you could use "maximum-paths ibgp unequal-cost 2 import 4" to ensure your VRF's will import 4 BGP routes. If a route-reflector fails (I'm assuming there are 2 for this) you will still have the 2 routes in your VRF. HTH Nick -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of David Freedman Sent: 05 August 2010 15:29 To: [email protected] Cc: [email protected] Subject: Re: [c-nsp] mpls route target export question We generally do one RD, RT per VRF, same RD across multiple PEs the VRF is configured (extended import/export policies aside) We also attach standard communities to VRF prefixes (yes, astonishing thing to do) since our standard community scheme does all the stuff like identifying the originating router/site/customer/routing policy etc.. We currently use a system of route reflectors and have no issue where we have multi-PE homed CE (other than where we do as-override where we set SoO per PE) would be interested on some expansion of oli's comments on convergence, and why differing RDs for the same prefix would be a good thing (I'm imagining perhaps if you want to do multipath then they are considered multiple paths as opposed to simply just selecting one because RD is the same?) Dave. Information in this email including any attachments may be privileged, confidential and is intended exclusively for the addressee. The views expressed may not be official policy, but the personal views of the originator. If you have received it in error, please notify the sender by return e-mail and delete it from your system. You should not reproduce, distribute, store, retransmit, use or disclose its contents to anyone. Please note we reserve the right to monitor all e-mail communication through our internal and external networks. SKY and the SKY marks are trade marks of British Sky Broadcasting Group plc and are used under licence. British Sky Broadcasting Limited (Registration No. 2906991), Sky Interactive Limited (Registration No. 3554332), Sky-In-Home Service Limited (Registration No. 2067075) and Sky Subscribers Services Limited (Registration No. 2340150) are direct or indirect subsidiaries of British Sky Broadcasting Group plc (Registration No. 2247735). All of the c! ompanies mentioned in this paragraph are incorporated in England and Wales and share the same registered office at Grant Way, Isleworth, Middlesex TW7 5QD. _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
