MP-BGP (Multiprotocol BGP) is an extensions to BGP protocol. Standard BGP only supports IPv4 unicast address family, whereas MP-BGP supports more than 15 different BGP address families.
RFC4760 defines the extensions for BGP protocol and states that ” in order to bring extra functionality to BGP protocol, new BGP AFI (Address Family Identifier) and BGP SAFI (Sub Address Family Identifier) is introduced”.
Multi protocol BGP supports IPv4 and IPv6 address families and their unicast and multicast variants.
MPBGP also supports Layer 2 VPN address families. EVPN (Ethernet VPN) is a mechanism which the mac addresses are exchanged between PE devices over BGP control plane. Read more