Experts pointed out the difference between unicast messages and multicast messages in network connection.

Unicast is a one-to-one communication mode between hosts. Switches and routers in the network only forward data without copying it. If 10 clients need the same data, the server needs to transmit them one by one and repeat the same work 10 times. However, due to its timely response to every customer, all web browsing now adopts IP unicast protocol. Routers and switches in the network select transmission paths according to their destination addresses and transmit IP unicast data to their designated destinations.

Multicast means that hosts who join the same group can receive all the data of this group, and switches and routers in the network only copy and forward the data they need to those who need it. A host can ask a router to join or leave a group. Routers and switches in the network selectively copy and transmit data, that is, only the data in the group are transmitted to those hosts who join the group. In this way, data can be transmitted to multiple required hosts (joining the group) at one time, while ensuring other communication of other unnecessary hosts (not joining the group).

To put it bluntly, the laboratory uses multicast and the dormitory uses unicast.

A message is just a data unit.