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Researchers find fault with Win2K TCP/IP gateway services

By CHARLES BRUNO
ITclarity, 06/19/00

Network managers who think Windows 2000 will make life a dream will be in for a rude awakening if they plan to use the operating system's TCP/IP gateway services mechanism.

ITclarity researchers are finding the operating system's Dead Gateway Detection and Recovery (DGDR) mechanism is a complex -- and often unreliable -- solution to a straightforward problem.

Typically, every Windows station running TCP/IP is configured to use a single other station on its local TCP/IP subnetwork as its "Default Gateway," according to Tolly Research CTO Kevin Flood. (Note: Gateway and router are synonymous.)

The default gateway is the router port to which stations direct traffic that leaves the local IP subnetwork -- either to a station in the next building or across the Internet on the other side of the globe. Earlier versions of the Windows TCP/IP implementation allowed only a single entry for the "default gateway." You had to choose one link between your station and the rest of the IP universe. If that gateway collapsed, your only recourse was to "hand-configure" a different gateway and reboot every affected machine. Hardly a solution.

Windows 2000's new TCP DGDR implements code that allows the network manager to create a list of default gateways. Should the first one become unavailable, TCP/IP automatically switches to the next.

But, according to Flood, "It sounds a lot simpler than it really is. For one thing, it doesn't even work unless both ends of the session implement DGDR -- and that means Windows 2000 or late service packs on NT 4. And, while our research shows that the code performs adequately when the failure occurs BEFORE the session starts, we are getting very erratic results when failures are introduced when the session is in progress," he adds.

"Frankly," Flood says, "that is where it is the most important. If you are running a massive data mover application that takes hours to run and the failure occurs 95% of the way through, do you really want to have to start at the beginning?"

Microsoft introduced DGDR into several earlier versions of 32-bit Windows via service packs but the Tolly Research team cautions that network managers should expect to find differences in configuration options and default settings as the code evolved to its present stage.

The above information is derived from an ITclarity research track report. To purchase a subscription to Tolly Research's ITclarity service, click here.

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About Tolly Research

Tolly Research, provider of ITclarity, is a technology research firm based in Brielle, N.J., that specializes in testing-based research. Tolly Research provides accurate test results, insightful analysis, and practical recommendations for leading-edge technologies required by network professionals. While many businesses have specific implementation issues, there is a broad base of technology research that is applicable to all organizations. Tolly Research offers a more cost-effective method of gathering data than committing internal resources to tackle each new technology. For more information on Tolly Research, point your browser to www.tollyresearch.com, send e-mail to itclarity@tollyresearch.com or call 732-292-9411.