Configuring BGP, MPLS, RSVP, and an IGP on the PE and Core Routers for Draft Rosen VPNs
To send multicast traffic across a Layer 3 VPN, you must configure network protocols to handle intradomain routing (an interior gateway protocol [IGP], such as Open Shortest Path First [OSPF] or Intermediate System-to-Intermediate System [IS-IS]), interdomain routing (Border Gateway Protocol [BGP]), label switching (Multiprotocol Label Switching [MPLS]), and path signaling (Resource Reservation Protocol [RSVP]). For more information about these protocols and examples of how to configure these protocols to support a Layer 3 VPN, see the Junos VPNs Configuration Guide.
In multicast Layer 3 VPNs, the multicast PE routers must use the primary loopback address (or router ID) for sessions with their internal BGP peers. If the PE routers use a route reflector with next-hop self-configured, Layer 3 multicast over VPN does not work because PIM cannot transmit upstream interface information for multicast sources behind remote PE routers into the network core. Multicast Layer 3 VPNs require the BGP next-hop address of the VPN route to match the BGP next-hop address of the loopback VRF instance address.