3Com Switch 7750 Configuration Guide Guide

378 CHAPTER 39: MULTICAST OVERVIEW
■ Optimal performance: Multicast reduces redundant traffic.
■ Distributive application: Multicast makes multiple-point application possible.
Application of multicast
The multicast technology effectively addresses the issue of point-to-multipoint
data transmission. By enabling high-efficiency point-to-multipoint data
transmission, over an IP network, multicast greatly saves network bandwidth and
reduces network load.
Multicast provides the following applications:
■ Applications of multimedia and flow media, such as Web TV, Web radio, and
real-time video/audio conferencing.
■ Communication for training and cooperative operations, such as remote
education.
■ Database and financial applications (stock), and so on.
■ Any point-to-multiple-point data application.
Multicast Architecture The purpose of IP multicast is to transmit information from a multicast source to
receivers in the multicast mode and to satisfy information requirements of
receivers. You should be concerned about:
■ Host registration: What receivers reside on the network?
■ Technologies of discovering a multicast source: Which multicast source should
the receivers receive information from?
■ Multicast addressing mechanism: Where should the multicast source transports
information to?
■ Multicast routing: How is information transported?
IP multicast is a kind of peer-to-peer service. Based on the protocol layer sequence
from bottom to top, the multicast mechanism contains addressing mechanism,
host registration, multicast routing, and multicast application, as shown in
Figure 88:
Figure 88 Architecture of the multicast mechanism
Mult ic as t
route
Hos t
registration
Addressing
mec hanis m
Multicast
application
Hos t
registration
Addressing
mechanism
……
……
Multicast
source
(Host)
Mult ic as t r out e r
Rec eiv er
(Host)
Mult ic as t
route
Hos t
registration
Addressing
mechanism
Multicast router
Mult ic as t
application
Hos t
registration
Addressing
mec hanis m
……
Mult ic as t
route
Hos t
registration
Addressing
mec hanis m
Multicast
application
Hos t
registration
Addressing
mechanism
……
……
Multicast
source
(Host)
Mult ic as t r out e r
Rec eiv er
(Host)
Mult ic as t
route
Hos t
registration
Addressing
mechanism
Multicast router
Mult ic as t
application
Hos t
registration
Addressing
mec hanis m
……