R3303-HP HSR6800 Routers IP Multicast Configuration Guide
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Configuring MBGP
The term "router" in this document refers to both routers and routing-capable Ethernet switches.
MBGP overview
BGP-4 can carry routing information for IPv4 only. IETF defined Multiprotocol Border Gateway Protocol
(MP-BGP) to extend BGP-4 so that BGP can carry routing information for multiple network-layer protocols.
For a network, the topology for multicast might be different from that for unicast. To distinguish them, the
MP-BGP enables BGP to carry the unicast Network Layer Reachability Information (NLRI) and multicast
NLRI separately. The multicast NLRI performs an RPF check exclusively. In this way, route selection for a
destination through the unicast routing table and through the multicast routing table have different results,
ensuring consistent unicast forwarding and normal multicast between domains. For more information
about RPF, see "Configuring multicast routing and forwarding."
MP-BGP is defined in RFC 2858 (Multiprotocol Extensions for BGP-4). The application of MP-BGP for
multicast is called Multicast BGP (MBGP).
This document covers configuration tasks related to multiprotocol BGP for IP multicast only. For more
information about BGP, see Layer 3—IP Routing Configuration Guide.
Protocols and standards
• RFC 2858, Multiprotocol Extensions for BGP-4
• RFC 3392, Capabilities Advertisement with BGP-4
• draft-ietf-idmr-bgp-mcast-attr-00, BGP Attributes for Multicast Tree Construction
• RFC 4271, A Border Gateway Protocol 4 (BGP-4)
• RFC 5291, Outbound Route Filtering Capability for BGP-4
• RFC 5292, Address-Prefix-Based Outbound Route Filter for BGP-4
MBGP configuration task list
Task Remarks
Configuring basic MBGP functions Required.
Controlling route
advertisement and
reception
Configuring MBGP route redistribution Required.
Configuring default route redistribution into MBGP Optional.
Configuring MBGP route summarization Optional.
Advertising a default route to an IPv4 MBGP peer or peer group Optional.
Configuring outbound MBGP route filtering Optional.
Configuring inbound MBGP route filtering Optional.