1-11 MBGP ConfigurationThe term “router” refers to a router or a Layer 3 switch in this document.When configuring MBGP, go to these sections for information you are interested in:z MBGP Overviewz Protocols and Standardsz MBGP Configuration Task Listz Configuring MBGP Basic Functionsz Controlling Route Advertisement and Receptionz Configuring MBGP Route Attributesz Tuning and Optimizing MBGP Networksz Configuring a Large Scale MBGP Networkz Displaying and Maintaining MBGPz MBGP Configuration ExampleMBGP OverviewBGP-4 is capable of carrying routing information for IPv4 only. IETF defined multiprotocol BGPextensions to carry routing information for multiple network layer protocols.For a network, the multicast topology may be different from the unicast topology. To meet therequirement, the multiprotocol BGP extensions enable BGP to carry the unicast Network LayerReachability Information (NLRI) and multicast NLRI separately, and the multicast NLRI is used toperform reverse path forwarding (RPF) exclusively. In this way, route selection for a destination throughthe unicast routing table and through the multicast routing table will have different results, ensuringnormal unicast and multicast routing.Multi-protocol BGP is defined in RFC 2858 (Multiprotocol Extensions for BGP-4).Multi-protocol BGP for IP multicast is referred to as Multicast BGP (MBGP) for short.z This document covers configuration tasks related to multiprotocol BGP for IP multicast only. Forinformation about BGP, refer to BGP Configuration in the IP Routing Volume.z For information about RPF, refer to Multicast Routing and Forwarding in the IP Multicast Volume.
