Using a BGP VPNv6 RR can reduce the number of MP-IBGP connections between PEs. The RR not only reduces the burden on PEs, but also facilitates network maintenance and management.
A BGP speaker does not advertise the routes learned from an IBGP peer to other IBGP peers. To enable a PE to advertise the routes of the VPN that the PE accesses to BGP-VPNv6 peers in the same AS, the PE must establish IBGP connections to all peers to directly exchange IPv6 VPN routing information. In other words, MP-IBGP peers must be fully meshed. If there are n PEs (including ASBRs) in an AS, n x (n – 1)/2 MP-IBGP peer relationships need to be established. A large number of IBGP peers consume a great number of network resources.
To resolve this issue, use an RR to reflect routes. In an AS, one device serves as an RR to reflect VPNv6 routes; the other PEs and ASBRs serve as RR clients. An RR can be a P, PE, ASBR, or other type of device.
Configure a routing protocol on the MPLS backbone network for IP connectivity.
Establish LSPs or MPLS TE tunnels between the RR and all PEs serving as clients.
Configure the extended community attribute if a reflection policy needs to be applied to VPNv6 routes.