Multicast Explained in Flash 10.1 P2P
July 1st, 2010
Multicast is one of the features of Flash Player 10.1 and it enables you to distribute NetStreams across the peer-to-peer mesh. It can be audio, video or even pure data stream (AMF3) - the data stream can be very handy for games, it’s much better for such purpose (like sending realtime positions, directions) than using Posting as Posting is more optimized for large number of senders to send something - like chat, status change and so on.
Difference between Unicast and Multicast
Unicast
Unicast simply delivers streams from a server to n clients. For this purpose you can use Flash Media Server and TCP protocols such as RTMP/T/S/E or HTTP protocol. Unicast also costs you a lot of resources -> 1 MBps stream delivered to 1000 clients means 1 GB upstream from server - which is CPU demanding and network transit is also huge.