They carry files of size F packets.
All packets have equal size.
Time is divided into slots. Each user can transmit at most one packet per slot. The server is located at a round trip propagation time of 2 D slots from the user, has a buffer size of B packets and a capacity of C packets per slot. We define the waiting time of the customer to be the time interval between the arrival of the customer and the completion of transmission of the entire file by the server. The goal is to devise control algorithms that minimize the expected waiting time of a customer.