Editing Border Gateway Protocol (section)

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{{short description|Protocol for communicating routing information on the Internet}}
{{Redirect|BGP}}

{{Infobox networking protocol
| image        = BGP FSM.svg
| caption      = BGP state machine
| abbreviation = BGP
| purpose      = exchange [[Internet Protocol]] routing information
| date         = {{Start date and age|1989|06|01}}<ref>{{cite web |title=History for rfc1105 |date=June 1989 |url=https://datatracker.ietf.org/doc/rfc1105/history/ |publisher=[[IETF]] |access-date=1 December 2023}}</ref>
| based on     = [[Exterior Gateway Protocol|EGP]]
| osilayer     = [[Application layer]]
| ports        = tcp/179
| rfcs         = {{slink||Standards documents}}
}}
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'''Border Gateway Protocol''' ('''BGP''') is a standardized [[exterior gateway protocol]] designed to exchange [[routing]] and reachability information among [[autonomous system (Internet)|autonomous systems]] (AS) on the [[Internet]].<ref name=orbit>{{cite web |url=http://www.orbit-computer-solutions.com/BGP.php |title=BGP: Border Gateway Protocol Explained |access-date=2013-10-08 |url-status=dead |archive-url=https://web.archive.org/web/20130928115120/http://www.orbit-computer-solutions.com/BGP.php |archive-date=2013-09-28 |website=Orbit-Computer Solutions.Com}}</ref> BGP is classified as a [[path-vector routing protocol]],<ref>{{cite web |title=Network Routing with Path Vector Protocols: Theory and Applications|url=https://conferences.sigcomm.org/sigcomm/2003/papers/p49-sobrinho.pdf |archive-url=https://web.archive.org/web/20100714080202/http://conferences.sigcomm.org/sigcomm/2003/papers/p49-sobrinho.pdf |archive-date=2010-07-14 |url-status=live |access-date=March 16, 2018 |date=2003 |last=Sobrinho |first=João Luís}}</ref> and it makes routing decisions based on paths, network policies, or rule-sets configured by a [[network administrator]].

BGP used for routing within an autonomous system is called '''Interior Border Gateway Protocol''' ('''iBGP'''). In contrast, the Internet application of the protocol is called '''Exterior Border Gateway Protocol''' ('''EBGP''').