{"draft":"draft-ietf-idr-bgp4-26","doc_id":"RFC4271","title":"A Border Gateway Protocol 4 (BGP-4)","authors":["Y. Rekhter, Ed.","T. Li, Ed.","S. Hares, Ed."],"format":["ASCII","HTML"],"page_count":"104","pub_status":"DRAFT STANDARD","status":"DRAFT STANDARD","source":"Inter-Domain Routing","abstract":"This document discusses the Border Gateway Protocol (BGP), which is an\r\ninter-Autonomous System routing protocol.\r\n\r\nThe primary function of a BGP speaking system is to exchange network\r\nreachability information with other BGP systems.  This network\r\nreachability information includes information on the list of\r\nAutonomous Systems (ASes) that reachability information traverses.\r\nThis information is sufficient for constructing a graph of AS\r\nconnectivity for this reachability from which routing loops may be\r\npruned, and, at the AS level, some policy decisions may be enforced.\r\n\r\nBGP-4 provides a set of mechanisms for supporting Classless\r\nInter-Domain Routing (CIDR).  These mechanisms\r\ninclude support for advertising a set of destinations as an IP prefix, and\r\neliminating the concept of network \"class\" within BGP.  BGP-4 also\r\nintroduces mechanisms that allow aggregation of routes, including\r\naggregation of AS paths.\r\n\r\nThis document obsoletes RFC 1771.  [STANDARDS-TRACK]","pub_date":"December 2005","keywords":["BGP-4","routing"],"obsoletes":["RFC1771"],"obsoleted_by":[],"updates":[],"updated_by":["RFC4724","RFC6286","RFC6608","RFC6793","RFC7606","RFC7607","RFC7705","RFC8212","RFC8654","RFC9072","RFC9687","RFC9774"],"see_also":[],"doi":"10.17487\/RFC4271","errata_url":"https:\/\/www.rfc-editor.org\/errata\/rfc4271"}