Bgp Overview; Bgp Features Supported By The S6700 - Huawei S6700 Series Configuration Manual

S6700 Series Ethernet Switches
Configuration Guide - IP Routing

7.1 BGP Overview

BGP is mainly used to control route transmission and select the optimal route.
The Border Gateway Protocol (BGP) is a dynamic routing protocol used between Autonomous
Systems (ASs). BGP-1 (defined in RFC 1105), BGP-2 (defined in RFC 1163), and BGP-3
(defined in RFC 1267) are three earlier-released versions of BGP. The current BGP version is
BGP-4 defined in RFC 4271.
As an exterior routing protocol on the Internet, BGP is widely used among Internet Service
Providers (ISPs).
Characteristics of BGP are as follows:
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BGP runs on the switch in either of the following modes:
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When BGP runs within an AS, it is called IBGP. When BGP runs between ASs, it is called
EBGP.

7.2 BGP Features Supported by the S6700

The system supports various BGP features, including route summarization, peer group, route
reflector, confederation, community, MP-BGP, BGP Tracking, route dampening, load
balancing, BGP next hop delayed response, BFD for BGP and BGP security.
Main Route Attributes
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NOTE
Unless otherwise stated, BGP stated in this document refers to BGP-4.
Different from the Internal Gateway Protocol (IGP) such as the Open Shortest Path First
(OSPF) and Routing Information Protocol (RIP), BGP is an Exterior Gateway Protocol
(EGP), which controls route advertisement and selects the optimal route between ASs rather
than discover or calculate routes.
BGP uses the Transport Control Protocol (TCP) with the port number being 179 as the
transport layer protocol. The reliability of BGP is thus enhanced.
BGP supports Classless Inter-Domain Routing (CIDR).
BGP transmits only the updated routes when routes are being updated. This reduces the
bandwidth occupied by BGP for route distribution. Therefore, BGP is applicable to the
Internet where a large number of routes are transmitted.
BGP eliminates routing loops by adding AS path information to BGP routes.
BGP provides rich routing policies to flexibly select and filter routes.
BGP can be easily extended and adapt to the development of networks.
Internal BGP (IBGP)
External BGP (EBGP)
Origin attribute
AS_Path attribute
Next_Hop attribute
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