1. BGP Multi-Protocol

The BGP protocol, as specified in RFC 4271, can only announce IPv4 unicast routes. The Multi-Protocol (MP) extension enables BGP to route new types of routes, in particular IPv6 routes and certain routes used in BGP/MPLS VPN networks.

MP-BGP identifies transported route protocols by combining two concepts:

• the [AFI] address family (see table 1 "AFI address families") which existed prior to MP-BGP;

• the [SAFI] address subfamily (see table 2 "SAFI address subfamilies") created by MP-BGP.

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