Bgp Overview - 3Com MSR 50 Series Configuration Manual

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BGP Overview

BGP C
ONFIGURATION
Border Gateway Protocol (BGP) is a dynamic inter-AS route discovery protocol.
When configuring BGP, go to these sections for information you are interested in:
"BGP Overview" on page 825
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"BGP Configuration Task List" on page 840
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"Configuring BGP Basic Functions" on page 841
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"Controlling Route Distribution and Reception" on page 843
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"Configuring BGP Routing Attributes" on page 846
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"Tuning and Optimizing BGP Networks" on page 849
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"Configuring a Large Scale BGP Network" on page 851
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"Configuring BGP Graceful Restart" on page 853
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"Displaying and Maintaining BGP Configuration" on page 855
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"BGP Typical Configuration Examples" on page 856
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"Troubleshooting BGP Configuration" on page 874
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Three early versions of BGP are BGP-1 (RFC1105), BGP-2 (RFC1163) and BGP-3
(RFC1267). The current version in use is BGP-4 (RFC1771). BGP-4 is rapidly
becoming the defacto Internet exterior routing protocol standard and is commonly
used between ISPs.
The characteristics of BGP are as follows:
Focusing on the control of route propagation and the selection of optimal
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routes rather than the discovery and calculation of routes, which makes BGP,
an external routing protocol different from internal routing protocols such as
OSPF and RIP
Using TCP as its transport layer protocol to enhance reliability
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Supporting CIDR
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Substantially reducing bandwidth occupation by advertising update routes only
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and applicable to advertising a great amount of routing information on the
Internet
Eliminating routing loops completely by adding AS path information to BGP
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routes
Providing abundant routing policies, allowing implementing flexible route
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filtering and selection
Easy to extend, satisfying new network developments
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