HP 6125G HP 6125G & 6125G/XG Blade Switches IP Multicast Configuration - Page 12

Multicast overview 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. By using 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 video conferencing, and other bandwidth-critical and time-critical information services. The term "router " in this document refers to both routers and Layer 3 switches. Unless otherwise stated, the term "multicast" in this document refers to IP multicast. Information transmission techniques The information transmission techniques include unicast, broadcast, and multicast. 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 Host A Source IP network Packets for Host B Packets for Host D Packets for Host E Receiver Host B Host C Receiver Host D Receiver Host E 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. 1