IP Multicast
A multicast is a single data stream sent from one source to a group of recipients.
Examples might be a stock ticker or live video feed. Figure 7-1 shows
an example multicast topology, as contrasted to unicast and broadcast.
Figure 7-1 Multicast Topology
GE
GE GE
FE FE FE FE
DS3 (~45MB)
In contrast, a unicast is traffic from one source to one destination (see Figure 7-2).
Figure 7-2 Unicast Topology
GE
GE GE
FE FE FE FE FE
DS3 (~45MB)
A broadcast is traffic from one source to all destinations (see Figure 7-3).
Broadcasts are not routed!