http://www.rfc-editor.org/rfc/rfc4760.txt
RFC 4760: Multiprotocol Extensions for BGP-4, T. Bates, R. Chandra, D. Katz, Y. Rekhter2007-01-01T23:00:00-00:00This document defines extensions to BGP-4 to enable it to carry routing information for multiple Network Layer protocols (e.g., IPv6, IPX, L3VPN, etc.). The extensions are backward compatible - a router that supports the extensions can interoperate with a router that doesn't support the extensions. [STANDARDS-TRACK]