Yes please -option d also known as option AB -it's the same as option b with addition of VRFs on the ASBRs -it might as well be viewed as a natural step between opt a and opt b
-opt ab offers the same great control over the routes advertised between ASes as opt a -though provides for better scalability by introducing mp-ebgp session between ASBRs By removing the VRFs from the ASBRs and turning off the default mp-ibgp behavior -option b doesn't suffer from some of the inherent drawbacks of opt ab like: Increased memory demands because ASBRs have to store routes in the per-vrf RIBs in addition to mp-bgp database Opt b has also streamlined the forwarding process by omitting the additional per-vrf ip lookup on the ASBRs The tradeoff is however -less control over the routes advertised between the AS domains One advantage that comes naturally with opt ab is -you don't need to worry about the import/export RTs not matching in two different ASes and configuring RT rewrites on ASBRs -opt ab will take care of that for you adam -----Original Message----- From: David Freedman [mailto:david.freed...@uk.clara.net] Sent: Friday, July 23, 2010 5:21 PM To: Vitkovsky, Adam Cc: Christopher Morrow; Michael Dillon; nanog@nanog.org Subject: Re: "vpn exchange point" If you are going to go multi-VLAN data plane (as opposed to multi-label) then 10A will cause you scaling issues as you'll need multiple BGP peers (or static routing), I'd prefer to use http://tools.ietf.org/html/draft-kulmala-l3vpn-interas-option-d-02 which already has implementations, i.e (albeit differently named) http://www.cisco.com/en/US/docs/ios/mpls/configuration/guide/mp_vpn_ias_optab.html Dave.
