How do we advertise these VPNv4 routes? That's what we need MP-BGP for. MP-BGP supports IPv4 unicast/multicast, IPv6 unicast/multicast and it has support for VPNv4 routes. To exchange VPNv4 routes, MP-BGP uses a new NLRI (Network Layer Reachability Information) format that has the following attributes: - RD (Route Distinguisher) - IPv4 prefix - Next Hop - VPN Label This is how PE routers exchange VPNv4 routes with each other.