Unicast - Unicast is a one-to-one connection in which one client receives a distinct stream from a server. A multicast on the other hand is a one-to-many connection in which multiple clients can receive the same stream from a server. To receive a multicast, a client must have access to a multicast-enabled network.  The web usually uses the unicast model (as compared to multicast).  https://en.wikipedia.org/wiki/Unicast