Concept Guide

Border Gateway Protocol (BGP)
Border Gateway Protocol (BGP) is an interdomain routing protocol that manages routing between edge routers.
BGP uses an algorithm to exchange routing information between switches enabled with BGP. BGP determines a path to reach a particular
destination using certain attributes while avoiding routing loops. BGP selects a single path as the best path to a destination network or
host. You can also inuence BGP to select dierent path by altering some of the BGP attributes.
Topics:
• BGP IP version 4 (BGPv4) Overview
• BGP Autonomous Systems
• Multiprotocol BGP
• Sessions and Peers
• BGP global and address family conguration
• BGP Attributes for selecting Best Path
• Implement BGP with Dell EMC Networking OS
• Conguration Information
• Basic BGP conguration tasks
• Enabling MBGP Congurations
• MBGP support for IPv6
• Conguring IPv6 MBGP between peers
• Example-Conguring IPv4 and IPv6 neighbors
• Congure IPv6 NH Automatically for IPv6 Prex Advertised over IPv4 Neighbor
• BGP Regular Expression Optimization
• Debugging BGP
BGP IP version 4 (BGPv4) Overview
This section provides a general description of BGPv4 as it is supported in the Dell EMC Networking Operating System (OS).
BGP protocol standards are listed in the Standards Compliance chapter.
BGP is an external gateway protocol (EGP) that transmits interdomain routing information within and between autonomous systems (AS).
An AS is an network managed by a single entity or administration. BGPv4 includes support for 4-byte autonomous system numbers and
multiprotocol extensions to allow BGP to exchange information. BGP also support multiple Layer 3 protocol address families including IPv4
and IPv6. The primary function of the BGP is to exchange network reachability information with other BGP systems. BGP generally
operates with an internal gateway protocol (IGP) such as open shortest path rst (OSPF) or router information protocol (RIP), allowing you
to communicate to external ASs smoothly. BGP adds reliability to network connections by having multiple paths from one router to another.
BGP uses a path-vector routing algorithm to communicate network information with other BGP congured devices. The network
information is exchanged as updates between BGP peers, which contains information about the network, attributes and AS that is used to
reach destination network. BGP selects a single path as a best path to a destination using best path selection algorithm.
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172 Border Gateway Protocol (BGP)