Network measurement of the VMTP request-response protocol in the V distributed system

Abstract

Communication systems are undergoing a change in use from stream to request-response or transaction communication. In addition, communication systems are becoming increasingly based on high-speed, low delay, low error rate channels. These changes call for a new generation of networks, network interfaces, and transport protocol design. The performance characteristics of request-response protocols on these high-performance networks should guide the design of this new generation, yet relatively little data of this nature is available. In this paper, we present some preliminary measurements of network traffic for a cluster of workstations connected by Ethernet running the V distributed operating system. We claim that this system, with its use of a high-speed local area network and a request-response transport protocol tuned for RPC, provides some indication of the performance characteristics for systems in the next generation of communication systems. In particular, these measurements provide an indication of network traffic patterns, usage characteristics for request-response protocols, and the behavior of the request-response protocol itself. These measurements suggest in general that a key design focus must be on minimizing network latency and that a request-response protocol is well-suited for this goal. This focus has implications for protocol design and implementation as well as for the design of networks and network interfaces.