TCP BUFFERING AND PERFORMANCE OVER AN ATM NETWORK

This paper reports a series of experiments to measure TCP performance when transferring data through an asynchronous transfer mode (ATM) switch, The results show that TCP buffer sizes and the ATM interface maximum transmission unit have a dramatic impact on throughput. We observe a throughput anomaly iu which an increase in the receiver's buffer size decreases throughput substantially. For example, when using a 16K octet send buffer and ATM Adaptation Layer 5 on a 100 megabit per second (Mb/s) ATM path, the mean throughput for a bulk transfer drops from 15.05 Mb/s to 0.322 Mb/s if the receiver's buffer size is increased from 16K octets to 24K octets. This paper analyzes the performance, explains the anomalous behavior, and describes a solution that prevents the anomaly from occurring.