H3C Technologies H3C S3100V2 Series Switches - Manual (Page 9)

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Multicast overview
NOTE:
This document 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 that coexists with unicast and broadcast, the multicast technique effectively addresses the
issue of point-to-multipoint data transmission. By enabling high-efficiency point-to-multipoint data
transmission over a network, multicast greatly saves network bandwidth and reduces network load.
The multicast technology enables a network operator to easily provide new value-added services, such
as live webcasting, web TV, distance learning, telemedicine, web radio, real-time video conferencing,
and other bandwidth-critical and time-critical information services.
Comparison of information transmission techniques
Unicast
In unicast transmission, the information source must send a separate copy of information to each host that
needs the information.
Figure 1 Unicast transmission
In Figure 1 , assume that Host B, Host D and Host E need the information. A separate transmission channel
must be established from the information source to each of these hosts.