TCP over wireless links with variable bandwidth
M. Yavuz, Farid Khafizov · 2003
We analyze the effects of TCP algorithms on data transmission over links with variable bandwidth. Significant throughput degradation is demonstrated due to factors such as spurious TCP retransmissions. The degradation is shown to be severe especially when high bandwidth resources are allocated to users for time periods during which multiple TCP segments are transmitted. The throughput degradation due to TCP effects is quantified for a wide range of burst and delay durations. A model for the TCP round trip time (RTT) is developed and validated with experimental results. This model is used to provide insight into spurious TCP retransmission problem and to suggest methods to alleviate it. Consequently, various methods are proposed and evaluated to improve the system throughput. Although we focus on IS-2000 links with finite burst mode of operation, the results would apply to different systems with shared resources and slow bandwidth allocation mechanisms.