Hello, friends!
I recently learned a lot about access network technologies and fault analysis in the forum.
I share with you what I know about multicast.
What Is Multicast
Multicast is a communication mode in which one information sender sends one copy of IP data package to a group of information recipients on an IP network. Other hosts on the network cannot receive this data package.
Comparison between multicast and unicast, and multicast and broadcast:
In the multicast mode, a single data stream is sent to a group of users at the same time. Only one copy of the same multicast data stream exists on each link. Compared with the unicast mode, in the multicast mode, the increase of users does not immediately increase the load of the network. Therefore, the server and the CPU can deal with a lighter load, reducing desired network bandwidths.
Multicast messages can be sent across different network segments and will not be received by users who are not interested in the messages. Compared with the broadcast mode, the multicast mode achieves a longer information transmission distance and ensures that information is transmitted to only interested recipients. Hence, information security can be guaranteed.
The preceding comparisons show that multicast effectively resolves the problem of P2MP transmission and implements efficient P2MP data transmission in IP networks.
Why Is Multicast Required
Traditional IP communications are implemented in unicast or broadcast mode.
Unicast: a P2P transmission mechanism. Unicast involves only one information sender and one information recipient.
Broadcast: a point-to-all-point transmission mechanism. Broadcast involves only one information sender and all the reachable information recipients in a LAN.
In broadcast IP communications, the source sends only one copy of packets to the broadcast address of the network. Then, the network copies these packets and sends them to all network segments for all routers and users, regardless of whether these routers and users require such data. In broadcast mode, if only a few users require such packets, network utilization is low and bandwidths are unnecessarily used. The users who do not require such data are adversely affected. In addition, a severe broadcast storm may occur due to routing loopback.
Traditional unicast and broadcast communications cannot meet P2MP service requirements. IP network development supports more network applications. In addition, some large amount of data needs to be sent in P2MP mode. In this case, multicast is introduced to meet these service requirements.
Multicast Applications
The multicast technology enables the device to provide value-added services, including live broadcast, IPTV, distance learning, TeleMedicine, network radio, live radio conference, and online game.
I hope it's helpful.
Thank you!
