Chapter 16. Multicast Protocols; Protocol Independent Multicast (Pim) - Samsung Ubigate iBG3026 Configuration Manual

Ubigate iBG3026 Configuration Guide
CHAPTER 16. MultiCast Protocols
This chapter describes the multicast routing protocols and how to configure
the multicast routing protocols. Please refer to the RFCs and the standards
documents for more detailed protocol specifications.

Protocol Independent Multicast (PIM)

Protocol Independent Multicast(PIM) protocols route multicast packets to
multicast groups. PIM is protocol independent because it can leverage
whichever unicast routing protocol is used to populate unicast routing table.
There are two modes of PIM protocol - Dense mode(DM) and Sparse mode
(SM). Ubigate iBG3026 supports SM but not DM. PIM-DM floods multicast
traffic throughout the network initially and then generates prune messages as
required. PIM-SM attempts to send multicast data only to networks which
have active receivers. This is achieved by having a common Rendezvous Point
(RP) known to the senders and receivers and by forming shared trees from the
RP to the receivers. The Protocol Independent Multicasting-Sparse Mode
(PIM-SM) is a multicast routing protocol designed to operate efficiently
across Wide Area Networks(WANs) with sparsely distributed groups. It helps
network nodes that are geographically dispersed to conserve bandwidth, and
reduces traffic by simultaneously delivering a single stream of information to
multiple locations. PIM-SM uses the IP multicast model of receiver-initiated
membership, supporting both shared and shortest-path trees, and uses soft-
state mechanisms to adapt to changing network conditions. It relies on a
topology-gathering protocol to populate a multicast routing table with routes.
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