It is a symptomatic measure of the message carrying capability of a network. It is termed as the total number of messages network can send in per unit time. To approximate the throughput, the capability of network and the messages number of really carried by the network are computed. Actually the throughput is just a part of its capacity. In 'interconnection network' traffic flow between nodes can be non uniform and it can be probable that a definite pair of nodes manages a disproportionately huge amount of traffic. These are known as 'hot spot'. The hot spot can act like a bottleneck and may reduce the performance of the entire network.