To help students to better understand the multicast in application
Understand and apply local network address Understand and apply the UDP and multicast datagrams in an application Network Java programming Design simple communication system and interface
Point-to-point connections handle a lot of communication needs, but passing the same information between many peers becomes challenging as the number of direct connections grows. Sending messages separately to each recipient consumes additional processing time and bandwidth, which can be a problem for applications such as group chat, streaming video or audio. Using multicast to deliver messages to more than one endpoint at a time achieves better efficiency because the network infrastructure ensures that the packets are delivered to all recipients. Unlike the most chat systems (e.g. YMessenger), this program does not need a server that dispatches messages but works in a distributed (i.e. peer-to-peer) style, allow chat in a LAN using multicast UDP datagrams.