BGP Overview

BGP is an exterior routing protocol that was developed for use in TCP/IP networks. The primary function of BGP is to allow different ASs to exchange network reachability information.

An AS is a set of routers that are under a single technical administration. This set of routers uses a different routing protocol, for example OSPF, for intra-AS routing. One or more routers in the AS are configured to be border routers, exchanging information with other border routers (in different ASs) on behalf of all of the intra-routers.

BGP can be used as an exterior border gateway protocol (referred to as EBGP), or it can be used within an AS as an interior border gateway protocol (referred to as IBGP).

For more information on BGP, refer to the following documents:

RFC 1745—BGP/IDRP for IP—OSPF Interaction
RFC 1771—Border Gateway Protocol version 4 (BGP-4)
RFC 1965—Autonomous System Confederations for BGP
RFC 1966—BGP Route Reflection
RFC 1997—BGP Communities Attribute
RFC 2385—Protection of BGP Sessions via the TCP RSA Data Security, Inc. MD5 Message-Digest Algorithm Signature Option
RFC 2439—BGP Route Flap Damping
RFC 2545—Use of BGP-4 Multiprotocol Extensions for IPv6 Inter-Domain Routing
RFC 2796—BGP Route Reflection - An Alternative to Full Mesh IBGP
RFC 2918—Route Refresh Capability for BGP-4
RFC 3392—Capabilities Advertisement with BGP-4
RFC 4271—Border Gateway Protocol 4 (BGP-4)
RFC 4360—BGP Extended Communities Attribute
RFC 4456—BGP Route Reflection: An Alternative to Full Mesh Internal BGP (IBGP)
RFC 4486—Subcodes for BGP Cease Notification Message
RFC 4724—Graceful Restart Mechanism for BGP
RFC 4760—Multiprotocol Extensions for BGP-4
RFC 4893—BGP Support for Four-octet AS Number Space
RFC 5396—Textual Representation of Autonomous System (AS) Numbers
draft_ieft_idr_restart_10.txt—Graceful Restart Mechanism for BGP

Note

ExtremeXOS supports BGP version 4 only, and does not support connections to peers running older versions of BGP.

For complete information about software licensing, including how to obtain and upgrade your license and what licenses are appropriate for these features, see the ExtremeXOS and Switch Engine 31.7 Feature License Requirements document..