Configuring mbgp, Mbgp overview, Protocols and standards – H3C Technologies H3C S12500 Series Switches User Manual

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Configuring MBGP

The term "router" in this chapter refers to both routers and Layer 3 switches.
This chapter covers configuration tasks related to multiprotocol BGP for IP multicast only. For more

information about BGP, see Layer 3—IP Routing Configuration Guide.

MBGP overview

BGP-4 can carry routing information for IPv4 only. IETF defined multiprotocol BGP extensions to carry

routing information for multiple network layer protocols.
For a network, the multicast topology might be different from the unicast topology. To meet the
requirement, the multiprotocol BGP extensions enable BGP to carry the unicast Network Layer

Reachability Information (NLRI) and multicast NLRI separately, and the multicast NLRI performs reverse

path forwarding (RPF) exclusively. In this way, route selection for a destination through the unicast routing

table and through the multicast routing table will have different results, ensuring normal unicast and
multicast routing. For more information about RPF, see "Configuring multicast routing and forwarding."
Multi-protocol BGP is defined in RFC 2858 (Multiprotocol Extensions for BGP-4).
Multi-protocol BGP for IP multicast is referred to as Multicast BGP (MBGP) for short.

Protocols and standards

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RFC 2858, Multiprotocol Extensions for BGP-4

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RFC 3392, Capabilities Advertisement with BGP-4

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draft-ietf-idmr-bgp-mcast-attr-00, BGP Attributes for Multicast Tree Construction

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RFC 4271, A Border Gateway Protocol 4 (BGP-4)

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RFC 5291, Outbound Route Filtering Capability for BGP-4

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