What is Multicast
The entire communication system throughout the world has come to be carried out through the internet with the computer being a key element in it. Faster and faster communication and more places to communicate with are the vital operating phrases of the communication technology. With that in mind technologies have developed the multicast system. This feature enables you to send information or message to a set of computers located at different places from your computer, simultaneously without any time gap.
Copies are created automatically only if required in other network features like routers. The Internet Protocol is used for multicast operations. The IP multicast is already being used in internet TV and streaming media. In IP multicast it is visible at the routing level in which the paths of optimal distribution are created by the routers. The multicast way of simultaneous delivery is also termed differently by different systems but the purpose and method of delivery happen remain to be same. While using the IP multicast prior intimation to the recipients is not required.
The recipients need not know who the other recipients are. The infrastructure is quite efficient because the sender is assured that his package is delivered to all the receivers without fail. There is no need to replicate the package. Protocols have been developed to ensure reliability of multicast. These protocols have the ability to detect any message is lost in transmission and redo the transmission in addition to what has been done by IP multicast.
There is widespread use of IP multicast. It is very popular among commercial establishments, private enterprises, stock exchanges and multimedia etc. IP TV application is immensely popular because it is a great help in distance learning. Some companies choose it for televising their meetings also. Efforts are being made to simplify the multicast system because of the very wide applications. The disadvantage in IP multicast is that it is not workable in case a good many number of trees are involved.
XCAST has come as an alternative to IP multicast providing for a wider range of recipients. It assumes that the receiving stations of messages should be known clearly so that proper distribution tree is generated and allocation of resources by network handling the traffic is done in advance. There are other technologies for multicast purposes which are not based on IP. One of them is IRC, catering to small groups. There is another one called PSYC technology which is very much less known used for conferences. The concept of multicast has made several operators to enter the field.