Abstract

Connectware commissioned The Tolly Group, as part of its 1994 Industry Benchmark for Local Token Ring Bridges, to evaluate the TokenSwitch 3000 with the main focus on measuring local Token Ring bridge performance across source-route bridging, IP routing, and IPX routing scenarios. The report emphasizes frame-handling efficiency, maximum unidirectional throughput, and the ability of the bridge to sustain high offered loads without packet loss in IBM-compatible Token Ring environments.  

The Connectware TokenSwitch 3000, formerly associated with Acsys LAN Products Group, is presented as a two-port, multi-protocol bridge/router designed for 4 or 16Mbit/s Token Ring networks. According to the product-specification panel on page 3, it supports Source Route Bridging, IEEE 802.1 Spanning Tree, TCP/IP and IPX networking, OSPF and RIP for IPX routing, frame sizes up to 8,144 bytes, and management features including SNMP and IBM LAN Network Manager. Additional listed features include flash memory, a front-panel LCD display, and in-band management with remote download and configuration.  

Tolly’s benchmark suite examined overall throughput for source-route bridged frames and optionally for IP and IPX routed traffic, using seven frame sizes for SRB testing: 28, 64, 256, 512, 1,024, 2,048, and 4,096 bytes. As shown in the throughput chart on page 1, the TokenSwitch 3000 delivered 8.60Mbit/s at 28 bytes, 12.01Mbit/s at 64 bytes, 14.84Mbit/s at 256 bytes, 15.03Mbit/s at 512 bytes, 15.50Mbit/s at 1,024 bytes, 15.75Mbit/s at 2,048 bytes, and 15.86Mbit/s at 4,096 bytes. Tolly states that these results correspond to 38,400fps at 28-byte frames and 23,450fps at 64-byte frames, while near-wire-speed throughput, defined by Tolly as 90% or more of ring bandwidth, was achieved for 256-byte frames and larger.  

The report explains that bridge performance is shaped primarily by two factors: frame handling, measured in frames per second, and maximum total throughput without loss. Smaller frames impose higher processing overhead because Token Ring bridges forward traffic on a frame-by-frame basis, reducing effective data throughput at high frame rates. Even so, Tolly reports that the Connectware TokenSwitch 3000 successfully forwarded all maximum frame rates generated by the test bed without packet loss throughout the testing, and that IP and IPX routing throughput closely tracked the source-route bridging results. Overall, the report presents the TokenSwitch 3000 as a high-performing local Token Ring bridge/router that combines strong frame-processing capability with near-wire-speed throughput on larger frames and solid support for routed Token Ring traffic.