On Optimal Window Sizes in High Speed Data Networks with Non- Exponential Service Times

Using a simple windowing model, we extend Mitra's relationship between optimal window size and measured network round trip delay to more general situations. Mitra first derived his relationship from an analysis of product form closed queuing networks. Our results suggest that his relationship holds for networks with general packet service distributions, not just exponential. Our simple model is a single transmitter/receiver pair with window flow control similar to SNA session level pacing. On the limit that the network propagation delay is large, we use the Central Limit Theorem to directly derive Mitra's relationship.