why one need multistage interconnection networks for reducing crosspoint complexity - He should be able to explain the difference between call congestion and time congestion, the computation of blocking probabilities for blocking switches - various fundamental theorems to decide on strictly non-blocking, wide-sense non-blocking, rearrange-ably non-blocking properties of the network. He should able to compute the crosspoint complexity bounds and how they can be further improved. He should be able to explain the rearrangement algorithms in rearrange-ably non-blocking switches - He should be able to explain packet switching input and output queued switch performance, Banyan, Delta network construction and properties, self routing in the Delta networks, performance analysis in Delta networks, prove that the Shufflenet is a Delta network - He should be able to explain the SIP (session initiation protocol) functionality, various message types, data types, message interpretation, call management procedures