On the Asymptotic Analysis of Packet Aggregation Systems

In packet communication systems, a header is attached to the transmitted packet at each layer. The overhead due to the transmission of the individual header can have significant impact on the performance of the communication system especially when the system operates in the heavy load. In order to increase data throughput, a number of packets can be aggregated into a frame in a particular OSI layer. In this paper, we present a queuing model with batch service which describes a packet aggregation process for Poisson arrivals and Phase-type service time distributions of the transmitted packets. We focus on the asymptotic behavior of such systems providing a significant reduction in the numerical complexity of their solution and provide analysis of the end-to-end delay of a packet transmitted by the system. Simple expressions for bounds on the average total delay of a packet are obtained. Based on results of experiments with the analytical model, we provide the minimum header size for which packet aggregation improves the system performance. It is numerically shown that the impact of the variability of the packet service time is rather insignificant when the system load is moderate or low. We also examine numerically the accuracy of the bound on the average total packet delay.