An analytical model for buffer and trunk sizing and severe congestion avoidance in LAPD frame-relay networks

An analytic model is presented to deal with sizing and managing sources so that the severity of congestion can be minimized. This model does not account for packet loss and the consequent retransmission. However, it computes distributions of the number of packets of each type in the trunk buffer and the corresponding memory requirements, which can be used to estimate the probability of packet loss for a given buffer size. The model uses closed queuing analysis with simple approximations to account for the constraints imposed by window flow control. Some results derived from the model are presented and compared with those obtained through simulation. The analytical model can deal with the buffer sizing problem for high-speed trunks which can carry thousands of virtual circuits. It is demonstrated that with proper system sizing and management, network resources can be efficiently utilized.<>