A short block of data of fixed length and destination information.It is the unit in which information(a message)is transferred in a packet - switching network.Packets may consist of as many as8000bits, and more from noder to node in the network.

• 拥有指定长度和目的地信息的一小块数据。它是分组交换网络中信息（即报文）传递的单位。信息包可以由多达8000位组成，并且可以在网络中从一个网点转移到另一个网点。