Multicast is a protocol implemented in
all modern network hardware (switches,
routers). It is the best way to send a
single video stream to a group of machines.
In multicast streaming, the stream is
sent to a multicast IP address (the IP
addresses reserved for this purpose are
from 224.0.0.0 to 239.255.255.255). Any
machine on the network can join the multicast
group by sending a multicast request on
the network, and it will then receive
the stream. When it sends a request to
leave the group, it will automatically
stop receiving the stream. The advantage
of multicast streaming is that only the
machines that want to receive the stream
actually receive it, and the streaming
server only sends one stream to the designated
multicast IP address even if there are
multiple clients receiving it.
