Operation Manual – MulticastH3C S5500-EI Series Ethernet Switches Chapter 1 Multicast Overview1-5For a better understanding of the multicast concept, you can assimilate multicasttransmission to the transmission of TV programs, as shown in Table 1-1.Table 1-1 An analogy between TV transmission and multicast transmissionStep TV transmission Multicast transmission1 A TV station transmits a TVprogram through a channel.A multicast source sends multicastdata to a multicast group.2 A user tunes the TV set to thechannel. A receiver joins the multicast group.3The user starts to watch the TVprogram transmitted by the TVstation via the channel.The receiver starts to receive themulticast data that the source sendsto the multicast group.4 The user turns off the TV set ortunes to another channel.The receiver leaves the multicastgroup or joins another group.Note:z A multicast source does not necessarily belong to a multicast group. Namely, amulticast source is not necessarily a multicast data receiver.z A multicast source can send data to multiple multicast groups at the same time, andmultiple multicast sources can send data to the same multicast group at the sametime.1.1.3 Advantages and Applications of MulticastI. Advantages of multicastAdvantages of the multicast technique include:z Enhanced efficiency: reduces the CPU load of information source servers andnetwork devices.z Optimal performance: reduces redundant traffic.z Distributive application: Enables point-to-multiple-point applications at the price ofthe minimum network resources.II. Applications of multicastApplications of the multicast technique include:z Multimedia and streaming applications, such as Web TV, Web radio, and real-timevideo/audio conferencing.z Communication for training and cooperative operations, such as distance learningand telemedicine.z Data warehouse and financial applications (stock quotes).
