Abstract

SMC commissioned Tolly, as part of the 1994 Industry Benchmark for Local Token Ring Bridges, to evaluate the EliteSwitch ES/1, with the main focus on measuring local Token Ring bridge performance across source-route bridging and optional IP and IPX routing scenarios. The project examined frame-handling efficiency, maximum effective unidirectional throughput, and the platform’s ability to deliver near-wire-speed forwarding across two-port, four-port, and six-port Token Ring configurations.  

The December 1994 Technology Spotlight describes the SMC EliteSwitch ES/1 as a multi-port, multi-protocol LAN switch that supports SNMP-based network management. The tested unit ran software version 2.5x8 and used the Texas Instruments TMS380 Token Ring chipset with a Texas Instruments MAC. According to the product-specification panel on page 3, the platform supported 4 or 16Mbit/s Token Ring over STP and UTP media, along with Ethernet, Token Ring, FDDI, and HSSI. It also supported Transparent Bridging, Source Route Bridging, and Source Route Transparent Bridging, plus TCP/IP and IPX routing. Tolly notes additional features including extensive statistics, programmable filtering, translational switching, and virtual LAN support.  

Tolly’s benchmark measured maximum effective unidirectional throughput for specifically routed, non-broadcast source-route bridging frames using seven frame sizes: 28, 64, 256, 512, 1,024, 2,048, and 4,096 bytes. In the two-port tests described on page 2, the EliteSwitch ES/1 forwarded 23,293fps at 28 bytes, 18,189fps at 64 bytes, 6,708fps at 256 bytes, 3,610fps at 512 bytes, 1,874fps at 1,024 bytes, 957fps at 2,048 bytes, and 483fps at 4,096 bytes. Page 1 and the chart on that page emphasize that the switch achieved near-wire-speed performance, defined by Tolly as 90% or more of bandwidth, for 512-byte frames and larger. In the six-port benchmark on page 1, throughput per ring pair reached 13.73Mbit/s at 256-byte frames, 14.78Mbit/s at 512 bytes, 15.37Mbit/s at 1,024 bytes, 15.68Mbit/s at 2,048 bytes, and 15.86Mbit/s at 4,096 bytes.  

The report explains that the primary factors in local Token Ring bridge performance are frame handling, measured in frames per second, and maximum throughput without loss. Because Token Ring bridges forward on a frame-by-frame basis, small frames produce lower effective throughput due to the chipset’s frame-processing limits, while larger frames make it easier to approach wire speed. The four-port and six-port results on page 2 closely tracked the two-port trend, with six-port throughput measuring 6,706fps at 256 bytes, 3,609fps at 512 bytes, 1,876fps at 1,024 bytes, 957fps at 2,048 bytes, and 484fps at 4,096 bytes per ring pair. Tolly also notes that IP routing throughput tracked closely with the source-route bridging results. Overall, the report presents the SMC EliteSwitch ES/1 as a high-performance local Token Ring bridge/switch that delivered strong multi-port scalability, near-wire-speed forwarding on larger frames, and broad protocol and media support.