Microsoft KB Archive/199193

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NDIS 4.1 ATM Call Manager Fails to Properly Buffer ILMI Requests

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Q199193

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The information in this article applies to:


 * Microsoft NetShow Theater Server version 3.0

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SYMPTOMS
NetShow Theater Server may appear to stop responding or may report a variety of network errors due to a connectivity failure when operating in an ATM environment of FORE switches running ForeThought version 5.3. The ipatm -g and atmadm -a commands may take 30 to 60 minutes before returning a MAC address.

CAUSE
The NDIS 4.1 ATM Call Manager is failing to properly buffer Integrated Local Management Interface (ILMI) requests. When ILMI starts, the Fore Switch sends 12-15 requests to the client, all back to back. One of the key requests is to check whether the client's prefix registration table is empty. If the switch receives Nosuchname for that request, then the switch can provide the prefix to the client and then proceed to the ILMI processing state. The client then registers its address(es). Unfortunately, about 65 percent of the 12-15 requests get dropped by the Windows NT host. Eventually, the host may process the prefix request (between 30 to 60 minutes in lab tests). Previous to ForeThought version 5.3, ILMI 4.0, the Fore switch sent fewer requests, which increased the likelihood that the host would process the requests.

This affects all NetShow Theater Server configurations in an ATM environment using FORE ATM switches that are running ForeThought version 5.3.

RESOLUTION
A supported fix is now available from Microsoft, but it is only intended to correct the problem described in this article and should be applied only to systems experiencing this specific problem. This fix may receive additional testing at a later time, to further ensure product quality. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, please go to the following address on the World Wide Web:

http://support.microsoft.com/directory/overview.asp

NOTE: In special cases, charges that are normally incurred for support calls may be canceled, if a Microsoft Support Professional determines that a specific update will resolve your problem. Normal support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The following file corrects the issue described in this article:

"Cmatm.sys version 3.0.0.1355 (dated 10/21/98 10:13am and later)"

WORKAROUND
Increase the NDIS 4.1 ATM Call Manager ILMI buffer counter to 20 in the Cmatm.sys file.

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Use a production release of ForeThought prior to version 5.3.

STATUS
Microsoft has confirmed this to be a problem in NetShow Theater Server version 3.0.

MORE INFORMATION
To install this fix, do the following:


 * 1) Rename the existing Cmatm.sys file in the \WINNT\SYSTEM32\DRIVERS\ folder and copy the newer version 3.0.0.1355 into the same directory.
 * 2) Shutdown and restart the computer.

Additional query words:

Keywords :

Issue type : kbbug

Technology :