Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) - Manual (Page 374)

346 Multi-Service IronWare Routing Configuration Guide
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MBGP
This chapter provides details on how to configure Multi-protocol Border Gateway Protocol (MBGP).
MBGP is an extension to BGP that allows a router to support separate unicast and multicast
topologies. BGP4 cannot support a multicast network topology that differs from the network’s
unicast topology. MBGP allows you to support a multicast topology that is distinct from the
network’s unicast topology. For example, if you want to dedicate a link on your Internet router to
multicast traffic, use MBGP to handle the routes on that link.
NOTE
The IPv6 multicast address family for MBGP is supported. However, only static mroutes and directly
connected routes over IPv6 multicast enabled interfaces may be enabled for distribution.
MBGP provides the following benefits:
• You can support a network whose multicast topology is different from its unicast topology. Even
if the unicast and multicast networks have the same topologies, you can support different sets
of routing policies for unicast and multicast.
• You can use BGP4's powerful feature set with MBGP.
Figure 22 shows an example of a network that contains both a unicast topology and a multicast
topology. The unicast and multicast router in this example receives unicast and multicast routes
from the Internet. The router advertises the multicast routes to the multicast router and advertises
the unicast routes to the unicast router. Likewise, the unicast and multicast router can advertise
unicast routes received from the unicast router to the Internet, and can advertise multicast routes
received from the multicast router to the Internet.
FIGURE 22 MBGP used when multicast topology is different from unicast topology
An MBGP router learns MBGP routes from its neighbors in other ASs. An MBGP router also can
advertise MBGP routes to its neighbors. The implementation of MBGP enables you to advertise
multicast routes from the following sources:
• Explicitly configured network prefixes
• Static IP multicast routes
• Directly-connected multicast routes redistributed into MBGP.
You can configure an aggregate address to aggregate network prefixes into a single, more general
prefix for advertisement.
MBGP is described in detail in RFC 2858.