Cisco Systems Cisco Systems In certain situations, transporting a packet from one BGP speaker to another, the BGP next hop, requires that the packet be encapsulated by the first BGP speaker and decapsulated by the second. To support these situations, there needs to be some agreement between the two BGP speakers with regard to the "encapsulation information", i.e., the format of the encapsulation header as well as the contents of various fields of the header. The encapsulation information need not be signaled for all encapsulation types. In the cases where the signaling is required (such as L2TPv3, GRE with key), This draft specifies a method by which BGP speakers can signal encapsulation information to each other. The signaling is done by sending BGP updates using the "Encapsulation SAFI" and IPv4 or IPv6 AFI. In the cases where no encapsulation information needs to be signaled (such as GRE without key), this draft specifies a BGP extended community that can be attached to UPDATE messages that carry payload prefixes to indicate the encapsulation protocol type to be used.