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To find out, Network Computing and sister publication InternetWeek issued a challenge to ATM vendors: Design and deploy an ATM network that fosters distance-learning across a 100-kilometer wide-area link; allows for simultaneous transmission of data and video with guaranteed QoS (Quality of Service); and guarantees fault tolerance on the wide-area connection. Six vendors brought solutions to the test site at the University of Hawaii at Manoa: Bay Networks (now owned by Nortel Networks), Cabletron Systems, FORE Systems, Hitachi internetworking, Olicom and 3Com Corp. Cisco Systems indicated a desire to participate, but failed to respond to our request in time to be included in the testing.

The University of Hawaii at Manoa was selected as the test site for several reasons. It is located about 96 kilometers (60 miles) from the High Performance Computing Center (HPCC) on the island of Maui. High-speed access to HPCC is currently routed through a DS-3 circuit between Oahu and Maui. The test plan was developed with an eye toward satisfying the island's need for distance learning and high-speed computing. The challenge to vendors focused on the need for a tenfold increase in bandwidth, plus real-time video transmission, which is a prerequisite for the next-generation Hawaiian network.

Our 16-day testing period demonstrated the unfortunate reality of ATM today. The Olicom and Bay Networks solutions exhibited some interoperability problems associated with ATM signaling and LANE (LAN Emulation) in our test environment. A technology as mature as ATM really should be beyond such trivial issues. Once the kinks were worked out, all vendors' products successfully completed the testing process. But the fact remains that ATM is much more complex than its frame-based counterparts, and multivendor interoperability is not guaranteed in an ATM environment.

Price is another sticking point. Although solution prices have been falling during the past two years, OC-12 ATM technology is still an expensive proposition. Prices ranged from $120,000 for Cabletron's solution to more than $230,000 for 3Com's offering. The Cabletron, FORE Systems and Olicom offerings came within $11,000 of each other. Cabletron earned our Best Value award for its solution, which included advanced features such as MPOA (Multiprotocol Over ATM) and Gigabit Ethernet routing.

During our tests, we ran into interoperability problems between FORE Systems' ATM NICs and the vendors' switches; we did not test switch-to-switch interoperability. We solved most of the problems, but some answers eluded us--Olicom ultimately had to use its own ATM NICs; Bay Networks suffered transient problems that fortunately cleared up long enough for us to run and complete our tests. Other vendors resorted to downgrading code on the FORE Systems NICs to older, previously tested drivers.

Keep in mind, however, that our test was complex and application-specific. Although interoperability issues caused us some grief, nearly every vendor has demonstrated interoperability with FORE Systems NICs in the past. Vendors typically bring to our tests the latest and greatest code revisions for their products, many of which haven't been fully tested for interoperability. ATM is a proven technology, but it requires patience when you're integrating products from multiple vendors.