Unicast is a one-to-one transmission method. A single frame is sent from the source to a destination on a network. When this frame is received by the switch, the frame is sent on to the network, and the network passes the frame to its destination from the source to a specific destination on a network.
Multicast is a one-to-many transmission method. A single frame is sent from the source to multiple destinations on a network using a multicast address. When this frame is received by the switch, the frame is sent on to the network and the network passes the frame to its intended destination group.
Broadcast is a one-to-all transmission method. A single frame is sent from the source to a destination on a network using a multicast address. When this frame is received by the switch, the frame is sent on to the network. The network passes the frame to all nodes in the destination network from the source to an unknown destination on a network using a broadcast address. When the switch receives this frame, the frame is sent on to all the networks, and the networks pass the frame on to all the nodes. If it reaches a router, the broadcast frame is dropped.
