Analysis of Diskless Workstation Traffic on an Ethernet

摘要

This study analyzes the communication traffic on a medium-size Ethernet local area network that connects file servers to diskless workstations. The measurements differ from those of other studies in two important aspects. First, the Ethernet traffic is much higher. Second, the measurements are more accurate. For each packet, all the protocol information was extracted and recorded on tapes along with the packet arrival time. Less than one percent of the packets was lost. The clock used had a one-microsecond resolution. This paper describes the measurement methodology, present the traffic statistics, and compare our traffic characteristics with a previous study. The behavior is detailed for each of the protocols responsible for a significant proportion of the total traffic. Traffic patterns are highly skewed: + a single client workstation, under normal usage, can generate for and request from a file and paging server data amounting to more than 20 percent of the total raw Ethernet bandwidth. Protocol timers cause numerous, unnecessary retransmissions. The accurate tracing time allows for extensive study of the packet interarrival time and has provided strong grounds for the hypothesis that the arrival process is non-random. Network bandwidth may be a scarce resource in applications that involve high-performance virtual-memory diskless machines. A key prerequisite for the success of future diskless workstations will be the design of fast interactive communication protocols that function effectively under high network load. (JHD)