264. Introducing multicasting

Multicasting is like a flavor of internet broadcasting. We know that a TV station can broadcast (share) its signal from the source to all its subscribers or to everybody in a certain area. The exceptions are represented by the people who don’t have the proper receiver (equipment) or aren’t interested in this TV station.

From a computer perspective, the TV station can be considered a source that sends datagrams to a group of listeners/subscribers or simply destination hosts. While point-to-point communication is possible via the unicast transport service, in multicasting (sending datagrams from a source to multiple destinations in a single call) we have the multicast transport service. In the case of the unicast transport service, sending the same data to multiple points is possible via the so-called replicated unicast (practically each point receives a copy of the data).

In multicasting terms, the receivers of multicasted datagrams...