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Acceptance testing lets Bank of Montreal check vendor claims.

Organizations which do acceptance

< testing on their network

devices learn quickly whether their resources are maximizing performance. It's preventative maintenance--an essential process towards building a smoothly running network. "When you're dealing with complex

< systems, working with a tester that doesn't do real-time correlations between networks is like stabbing in the dark," says Ron Szpak, senior engineer of network design and integration at the Bank of Montreal. The bank has an ever-growing network < of banking computers, consisting of SNA, bisync and X.25 applications. Their network consists of branch networks, point of sale networks for Mastercard, shared automated teller machine (ATM) networks and connections to other banks' networks. "Our customers can't tolerate network

< disruptions," Szpak says. To this end, the Bank of Montreal does

< extensive certification before allowing new equipment on their network. This sometimes involves procedures as complicated as setting up test networks to verify the off-the-shelf and custom hardware they require. For intricate tasks, Ron Szpak has found that there is no substitute for a sophisticated tester with strong emulation and multiport capabilities. "Once we needed to connect a client

< with an SNA host to the shared bisync ATM network. Because the need was urgent, a quick analysis resulted in a single vendor's protocol converter that met bank and client requirements," he says. When the protocol converter was installed

< and configured, there were problems related to timing issues and to the mapping of bisync to/from SNA. "To isolate the problems, we connected

< an Idacom tester to both sides of the unit and recorded the incoming and outgoing traffic. We then faxed the vendor a time-stamped recording with the problem areas highlighted to expedite a quick fix," he says. "At first, he didn't believe it because < it showed what was happening on both networks in sync," Szpak says. As the tester is set up to test two ports, < it automatically synchronizes the two ports. The user doesn't need to compare unsynchronized outputs from two testers to guess at the delay time. He just uses the response time menu choice and the tester automatically calculates the exact response time to a five microsecond resolution. "The vendor showed the information < to one of their software engineers and he knew exactly what was happening--it was a protocol timing problem. The engineer changed one timing register. We downloaded new software from the vendor, and--bloom--it was working. "We then emulated the exact same situation

< again with the tester, to verify that it worked correctly, and it did. The whole thing was solved in five or six days." Acceptance testing also lets the bank

< verify vendors' claims of equipment performance. "There was a project to upgrade our

< existing ATM controller which multiplexed six ATMs onto a single higher-order line to the host. The upgraded controller was required to multiplex eight ports of six ATMs per port (48 ATMs total) onto one high order line. The device also had to support any combination of bisync and SNA device types," he recalls. To certify the vendor's product, Walter


Nieczyporowski, staff specialist, and Wen Huang, staff analyst, developed emulations of the low order bisync and SNA device types. Under program control, traffic

< volumes were varied from low, during which the controller operated properly, to high--at which point the processing delays within the controller approached two minutes. "We met with the vendor and discussed

< our results. He couldn't believe it, he thought we actually had 48 ATMs in our test lab. When we told him the traffic was simulated, he was skeptical. We demonstrated a test run and he had to concede that our test was valid. After discussions with the vendor, they fine-tuned some code and changed the worst case transaction times from more than 60 seconds to under 0.5 seconds. The test result from the PT was accurate and avoided haggling and finger pointing." Another complicated project that required < sophisticated protocol abilities was a secure customer banking link. "We eventually settled on a cost effective

< medium: Async. We use Datapac 3101 (Canada's X.25 network) service to a custom X.25 host we maintain. This has a lot of things going for it; the system isn't dedicated to one application. It's an application gateway to a multitude of services. But there was a catch--it isn't secure--so the link had to be encrypted, and it had to be verifiable as secure. We developed a spec and put it out to tender. "We required a system that would provide

< data encryption between a customer's async terminal and our X.25 host," Szpak says. Customers use the Datapac 3101 X.25 network to access the bank's X.25 host. "A company built our unit and we had

< to verify that it worked. To do that we wrote scripts on our Idacom testers that emulated and monitored all the possible situations that could arise while talking to our hosts," he explains. "We used two testers and monitored the

< traffic at every point in the communications between the terminal and our computer. "When something didn't work, the

< testers provided us with clear definitions of what was going wrong--there was no guesswork involved. We could turn around and give that clear cut information to the vendor and he would know how to fix it. "The whole process was not only

< beneficial to the vendor but also to the bank because the encryption units were not sent out to our customers with problems," Szpak concludes.

COPYRIGHT 1992 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1992 Gale, Cengage Learning. All rights reserved.

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Title Annotation:Data/Voice Test Equipment
Publication:Communications News
Date:May 1, 1992
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