Factors Influencing ATM Adapter Throughput

Analytical and experimental evaluations show that ATM adapters can perform quite close to their designed limits, provided that they are used in a properly configured environment with series resources capable of sustaining the desired throughputs. While the media speed may be 155, 100 or 25 Mbps, there are a number of factors that will determine the final achieved maximum throughput observed by a user of an ATM adapter. One is the overhead inherent to ATM, such as the 5 byte ATM header that accompanies every 48 bytes of data sent. Others are inherent in the protocol used in the communication layers above ATM (e.g., pacing and retransmission associated with TCP/IP). Still others are dependent upon the processor speed and operating system used by the adapter host system. This paper discusses those parameters that, based on our experience, can have a considerable impact on the throughput of an ATM adapter. Turboways 2 25, 100 and 155 ATM adapter measurements illustrate these issues. Thes..

High Performance Tuning Tips For Communications Adapters: Token Ring, Ethernet And Atm

In this paper, we will present performance tuning tips (including step-by-step instructions for modifying the appropriate parameters) for Ethernet, Token Ring and ATM adapters installed under some of the most common operating systems (Windows 95 and NT, NetWare, OS/2, and AIX). IBM communications adapters will be used as examples throughout. We will discuss the theory behind adapter performance tuning as we go. We will then discuss some workstation and networking hardware features, capacities, etc. that will affect final observed adapter performance. Finally, we will recommend some industry standard benchmarks that may be used to measure the performance resulting from the tuning process. ITIRC KEY WORDS Performance Tuning Ethernet Adapter Token Ring Adapter LAN Adapter ATM Adapter TCP/IP Tuning IPX Tuning iii iv CONTENTS ABSTRACT . . . . . . . . . . . . . . . . . . . . . iii ITIRC KEYWORDS . . . . . . . . . . . . . . . . . . iii INTRODUCTION . . . . . . . . . . . . . . . . . . . ..

Performance Considerations In Positioning Emerging Networking Technologies: Atm, Atm-To-The-Desktop And Switched/high-Speed Ethernet

In this paper, we present measured and simulated data that should allow the reader to objectively evaluate the relative performance merits of an ATM-to-the-Desktop vs. switched/high-speed Ethernet networking solution. The data and arguments presented herein should be combined with those presented in other documents regarding cost, network management complexity, Quality of Service support and other capabilities, etc. when any final assessment of the two technologies is made. While the study suggests that ATM provides the best overall performance, as both a backbone technology and end-to-end solution, because of the inherent advantage of fixed size ATM cell switching over variable sized Ethernet frame switching, it must be emphasized that the empirical data demonstrates that both technologies deliver excellent performance. The installation of Ethernet switches to an existing shared Ethernet LAN will provide a significant demonstrable improvement in performance, and will extend the life o..