Date Added: Feb 2013
Congestion is an important issue in the computer network. Congestion takes place when the numbers of packets sent are more than the capacity of the network. The primary cause of network congestion is that data in networks are overloaded and available resources such as bandwidth, buffers, queues, processor time etc. are inadequate to handle such traffic loads. Congestion occurs on shared networks when multiple users contend for the access to the same resources. Whenever sum of demands is more than the available resources, then queues are built up. This occurs because incoming packet rate is greater than the departure rate at routers and switches. Queues are built up whenever waiting is involved.