http://www.rfc-editor.org/rfc/rfc1397.txt
RFC 1397: Default Route Advertisement In BGP2 and BGP3 Version of The Border Gateway Protocol, D. Haskin1993-01-01T23:00:00-00:00This document speficies the recommendation of the BGP Working Group on default route advertisement support in BGP2 [1] and BGP3 [2] versions of the Border Gateway Protocol. [STANDARDS-TRACK]