ATM swims to strong showing in trans-Atlantic trial.

A recently-completed trial put ATM to the test in a trans-Atlantic, undersea fiber application involving Tandem Computers and two other users.

The 18-month trial involved Tandem, an unnamed financial institution (they are such secretive people) and a company described as a "media industry specialist." All three worked with Cable & Wireless (C&W) in the trial.

Tandem linked its European customer support applications into the company's main databases in Austin, Texas. For the trial, Tandem replaced an existing frame relay circuit and boasted big improvements in response times when it came to dealing with online customer inquiries.

Tandem's customer support system is a critical application for the company's European operations. Inquiries are routed through centers in Germany and the Netherlands into a European Customer Support Centre near Heathrow, England.

With the transmission delays on the existing frame relay link, the system sometimes "timed out" before the customer's inquiry was dealt with.

"Network latency is a vitally sensitive issue when you're dealing with international LAN connections," observes Warren Kirsch, information services director for Tandem, "especially if you've got a customer hanging on the phone waiting for a response to a problem."

The service through the C&W ATM link, Kirsch says, "has been of the highest level."

Tandem also used the link for monthly transfers of server reconfiguration data. The 1.75-gigabyte file transfers used to take 14 hours and required staffers to work on weekends to monitor the operation. With ATM, the data transfer took under two hours in most cases.

Patrick Tilley, project manager for C&W, says the carrier felt the best way to gain experience with ATM was to work with customers who "throw up new problems." The trial involved a 45 Mb/s (T3 rate) linkage using the PTAT U.S.-to-Britain undersea fiber cable, shared by the customers in the trial.

The trial tested ABR, VBR and CBR (available, variable and constant bit rate) services, including compressed voice using VBR. Among applications for the various users were LAN-TO-LAN links, multimedia video on demand, broadcast video and intra-company voice.

Putting ATM over the 45 Mb/s link did not cause any bottlenecking, assures Gian Dilawari, senior VP of engineering and information systems for C&W.

That is because C&W was very selective when it chose ATM switches for the trial, Dilawari says, especially when it came to their implementation of buffering and flow control. The carrier used StrataCom BPX and IPX switches.

"There is not necessarily one major driver for ATM," Dilawari says, with the trial customers finding many appropriate applications. "We learned there is fairly good demand for this trans-Atlantic type of traffic. Some customers are very eager to go into service with this."

However, Charlie Thompson, in marketing communications for C&W, explains that "The purpose of the trial was to do tests and establish the feasibility and logistics of offering a commercial service. All that data will be analyzed with a view to considering the options available to us."

What that boils down to is that for the moment the carrier has no concrete plans to convert the trial into a commercial service offering. They're not saying it won't become a commercial service, just that they can't gauge when it might.

The carrier is doing some other ATM trials around the globe, but most are domestically contained.

"Obviously the trial allowed us to get behind the hype of ATM and start to see more of the true usage," Tilley concludes. "I think you will see certain sectors that will be early adopters of ATM. It is a question of whether there is pentup demand because we have not had this wide area broadband capacity in the past.

"I think that is why we will start seeing early adopters with business-critical applications they are looking to roll out into the wide area. It is then a question of how quickly that rolls out to more than those niche sectors."