Multicast or multicasting is the process of transmitting data from a single source to a single multicast address, which is then distributed to an entire group of recipients. It’s similar to broadcasting, with the difference being that information is transmitted to specific users.
Because a server only needs to send each packet once and will reach all of the recipients, it’s useful for situations where a large number of receivers need to receive the same data. Since the replication and distribution of these packets is done by the network rather than the head end server, it scales well to extremely large numbers of receivers. Multicast is used in IPTV installations within, for example, companies, hotels, cruise ships, et cetera. But it is also used within the TV distribution networks, such as KPN and Ziggo. The networks are specially designed for this.
The biggest advantage of multicast is that it is a very efficient way to distribute video over a managed network. The network load remains within limits. The disadvantage is that the network has to be configured in a special way. The network administrator must have this knowledge to use multicast correctly.