TCP/IP behavior in a high-speed local ATM network environment

Abstract

The Internet TCP/IP protocol suite is the first higher-level protocol stack to be used on ATM based networks. High-speed networks reinstate the end-system as the communication path bottleneck. We show how the host architecture and host network interface are crucial for memory-to-memory TCP throughput. In addition, configurable parameters like the TCP maximum window size and the user data size in the send and receive system calls influence the segment flow and throughput performance. We present measurements done on Sparc2 and Sparc10 based machines for both generations of ATM-cards from FORE Systems. The first generation cards are based on programmed I/O. The second generation cards on DMA. To explain the variations in the throughput characteristics, we put small optimized probes in the network driver to log the segment flow on the TCP connections.