Multicast Overview; Introduction To Multicast; Comparison Of Information Transmission Techniques - 3Com 4500G Family Configuration Manual

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Multicast Overview

This manual chiefly focuses on the IP multicast technology and device operations. Unless otherwise
stated, the term "multicast" in this document refers to IP multicast.

Introduction to Multicast

As a technique coexisting with unicast and broadcast, the multicast technique effectively addresses the
issue of point-to-multipoint data transmission. By allowing high-efficiency point-to-multipoint data
transmission over a network, multicast greatly saves network bandwidth and reduces network load.
With the multicast technology, a network operator can easily provide new value-added services, such
as live Webcasting, Web TV, distance learning, telemedicine, Web radio, real-time videoconferencing,
and other bandwidth- and time-critical information services.

Comparison of Information Transmission Techniques

Unicast
In unicast, the information source (Source in the figure) needs to send a separate copy of information to
each host (Receiver in the figure) that wants the information, as shown in
1-1
Figure 1-1.