Abstract

Testing Remote Token Ring Bridges

This April 1994 Data Communications lab test, conducted by Kevin Tolly of The Tolly Group and David Newman of Data Communications, evaluated remote token ring bridges designed to reduce leased-line WAN costs through data compression. The article examined whether bridge vendors’ compression claims translated into meaningful throughput improvements when connecting 16Mbit/s token ring LANs across a simulated 56Kbit/s WAN link.

The lab tested seven remote token ring bridge products from Acsys, Advanced Computer Communications, Andrew, Develcon Electronics, Microcom, Olicom, and 3Com. Products were assessed for compression effectiveness, ease of configuration, WAN and LAN setup, filtering, management, documentation, support, WAN-speed support, and whether the product used hardware or software compression. The test bed connected two token ring LANs through a simulated WAN link and used several traffic patterns, including uncompressed ASCII data, precompressed data, and baseline traffic with compression disabled.

The results showed that compression could significantly improve effective throughput, but that vendor performance varied widely. Advanced Computer Communications’ ACS 4200 delivered the best compression result, achieving nearly 4.2:1 effective compression on ASCII data and earning a Data Communications “Tester’s Choice” designation. The lab praised ACC not only for its performance, but also for straightforward configuration and management. Develcon Electronics’ Token Ring Remote Bridge Model 200 also received a “Tester’s Choice” designation, combining solid performance, compact size, and ease of operation.

Other products showed different strengths. 3Com’s NetBuilder Token Ring Remote compressed ASCII data at nearly 4:1 and offered strong routing and filtering functions, but the article noted that its broader feature set could make configuration more complex for organizations using it only as a remote bridge. Microcom’s MBR/6003 exceeded 3:1 compression and was positioned as a good value for entry-level bridge buyers, with support for MNP compression and SNMP. Acsys’ Tokenmaster 5000 was easy to install and manage, but its compression results were lower than the top performers. Olicom’s Token Ring Remote Bridge 16/4 was competitively priced but trailed most of the field in compression and configuration simplicity. Andrew’s Pathwise 7622 offered useful configuration and management features, but produced the lowest compression result in the comparison.

The article emphasized that compression ratios alone did not tell the full story. Network managers also had to consider WAN speeds, maximum compression speed, filtering capabilities, support for LAN Network Manager or SNMP, ability to set WAN frame sizes, link-speed configuration, and whether compression could be enabled or disabled easily. The lab also warned that some compression gains could come with trade-offs, including added latency when bridges buffered frames before transmission.

Overall, the test concluded that remote token ring bridges could deliver meaningful WAN savings by improving effective throughput over low-speed leased lines. However, buyers needed to compare products carefully because compression performance, manageability, filtering, WAN flexibility, and ease of setup varied substantially. The best products combined strong compression with simple configuration and practical management features for distributed enterprise token ring environments.

Solutions Tested

Acsys — Tokenmaster 5000
Advanced Computer Communications — ACS 4200
Andrew Corp. — Pathwise/7622
Develcon Electronics — Token Ring Remote Bridge Model 200
Microcom — MBR/6003
Olicom USA — Token Ring Remote Bridge 16/4
3Com — NetBuilder Token Ring Remote