H3C Technologies H3C SecPath F1000-E - Manual (Page 13)

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packets to receivers located at different positions of the network, multicast routers on the forwarding
paths usually forward multicast packets received on one incoming interface to multiple outgoing
interfaces. Compared with a unicast model, a multicast model is more complex in the following aspects.
• To ensure multicast packet transmission in the network, unicast routing tables or multicast routing
tables (for example, the MBGP routing table) specially provided for multicast must be used as
guidance for multicast forwarding.
• To process the same multicast information from different peers received on different interfaces of the
same device, every multicast packet is subject to a reverse path forwarding (RPF) check on the
incoming interface. The result of the RPF check determines whether the packet will be forwarded or
discarded. The RPF check mechanism is the basis for most multicast routing protocols to implement
multicast forwarding.
NOTE:
For more information about the RPF mechanism, see Multicast Routing and Forwarding Configuration or
IPv6 Multicast Routing and Forwarding Configuration in the IP Multicast Volume.