Multiprotocol BGP Extensions (MP-BGP)
Conventional BGP4 was originally designed to carry routing information only for the IPv4 address family.
Realizing this limitation, the IETF is standardizing the Multiprotocol Extensions for BGP4. (RFC 2858)
The extensions allow BGP4 to carry routing information for multiple Network Layer protocols (IPv6, IPX, VPN-IPv4, etc.)