TCP/ATM experiences in the MAGIC testbed

This paper describes performance measurements taken in the MAGIC gigabit testbed relating to the performance of TCP in wide area ATM networks. The behavior of TCP with and without cell level pacing is studied. In particular, we focus on results that indicate that the TCP rate control mechanism alone is inadequate for congestion avoidance and control in wide-area gigabit networks. We also present results showing that TCP augmented by cell-level pacing addresses these problems and allows the full bandwidth capacity to be utilized. These results demonstrate the viability of high performance distributed systems based on wide area ATM networks given the proper ATM traffic management infrastructure.