3com 3.01.01 User Manual

C

HAPTER

 6: M

ULTICAST

 P

ROTOCOL

table independently provided for multicast (such as the MBGP multicast routing 
table). This check mechanism is the basis for most multicast routing protocols , 
which is known as a RPF (Reverse Path Forwarding) check. A multicast router 
uses the source address from the multicast packet to query the unicast routing 
table, or the independent multicast routing table, to determine the incoming 
interface at which the packet arrives. If a source tree is used, the source address 
is the address of the source host sending the multicast packet. If a shared tree 
is used, the source address is the address of the root of the shared tree. When 
a multicast packet arrives at the router, if RPF check succeeds, the packet will 
be forwarded according to the multicast forwarding entry. Otherwise, the 
packet will be dropped.

IP multicast technology effectively solves the problem of packet forwarding from 
single-point to multi-point. It implements high-efficient data transmission from 
single-point to multi-point in IP networks and can save a large amount of network 
bandwidth and reduce network loads. New value-added services that use 
multicast can be delivered, including direct broadcasting, Web TV, distance 
learning, distance medicine, net broadcasting station and real-time audio/video 
conferencing. 

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Multimedia and streaming media applications

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Communications of the training and corporate sites

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Data repository and finance (stock) applications 

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Any “point-to-multi-point” data distribution 

With the increase of multimedia services on IP networks, multicast has huge 
market potential.

A common multicast configuration covers both the multicast group management 
protocol and the multicast routing protocol. The configuration includes enabling 
multicast, configuring multicast forwarding boundary, and displaying multicast 
routing table and multicast forwarding table.

Common multicast configuration includes:

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Enable multicast first before enabling the multicast routing protocol. 

Perform the following configuration in system view.

Table 3   Enabling Multicast

Enable multicast