http://www.rfc-editor.org/rfc/rfc2842.txt
RFC 2842: Capabilities Advertisement with BGP-4, R. Chandra, J. Scudder2000-05-01T23:00:00-00:00This document defines new Optional Parameter, called Capabilities, that is expected to facilitate introduction of new capabilities in BGP by providing graceful capability advertisement without requiring that BGP peering be terminated. [STANDARDS-TRACK]