Ip Multicast Application; Pim-Dm; Introduction To Pim-Dm - Edge-Core ES3628EA User Manual

packet will be discarded elsewise.

16.1.4 IP Multicast Application

IP Multicast technology has effectively solved the problem of sending in single point
and receiving in multipoint. It has achieved the effective data transmission from a point to
multiple points, saved a great deal of network bandwidth and reduced network load.
Making use of the Multicast property of network, some new value-added operations can
be supplied conveniently. In Information Service areas such as online living broadcast,
network TV, remote education, remote medicine, real time video/audio meeting, the
following applications may be supplied:
1) Application of Multimedia and Streaming Media
2) Data repository, finance application (stock) etc.;
3) Any data distribution application of "one point to multiple points"
In the situation of more and more multimedia operations in IP network, Multicast
has tremendous market potential and Multicast operation will be generalized and
popularized.

16.2 PIM-DM

16.2.1 Introduction to PIM-DM

PIM-DM（Protocol Independent Multicast, Dense Mode）is a Multicast Routing
Protocol in dense mode which applies to small network. The members of multicast group
are relatively dense under this kind of network environment.
The working process of PIM-DM can be summarized as: Neighbor Discovery,
Flooding&Prune, and Graft.
1. Neigh hour Discovery
After PIM-DM router is enabled, Hello message is required to discover neighbors.
The network nodes which run PIM-DM use Hello message to contact each other.
PIM-DM Hello message is sent periodically.
2. Flooding&Prune of process
PIM-DM assumes all hosts on the network are ready to receive Multicast data. When
some Multicast Source begins to send data to a Multicast Group G, after receiving the
Multicast packet, the router will make RPF check first according to the Unicast table. If
the check passes, the router will create a (S, G) table entry and transmit the Multicast
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