1/07/2009

*cast: the any-, broad-, uni- and multi- ones

*cast means network addressing and routing schemes.

Anycast donates that data is routed to the "nearest" or "best" destination as viewed by the routing topology. In extrem scalable online web services, anycast may be used as the first level loadbalance solution. (DNS round robin)

Unicast transmission is the sending of information packets to a single destination. Its name is a little bit strange and the intention is to echo *cast style.

Multicast is a network addressing method for the delivery of information to a group of destinations simultaneously. It is useful for intranet applications such as video conference over IP and VOD services etc.

Broadcast refers to transmitting a packet that will be received (conceptually) by every device on the network. It is used widely in flooding messages when the destination address is unkown.

The following pictures illustrate the main concepts of each method:

Routing
Anycast
broadcast
multicast
unicast

Picture from Wikipedia

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