NDIS 4.1 ATM Call Manager Fails to Properly Buffer ILMI Requests

ID: Q199193

The information in this article applies to:

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 that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific 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 on support costs, please go to the following address on the World Wide Web:

http://www.microsoft.com/support/supportnet/overview/overview.asp


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)

NOTE: If this product was already installed on your computer when you purchased it from the Original Equipment Manufacturer (OEM) and you need this fix, please call the Pay Per Incident number listed on the above Web site. If you contact Microsoft to obtain this fix, and if it is determined that you only require the fix you requested, no fee will be charged. However, if you request additional technical support, and if your no-charge technical support period has expired, or if you are not eligible for standard no-charge technical support, you may be charged a non-refundable fee.

For more information about eligibility for no-charge technical support, see the following article in the Microsoft Knowledge Base:
Q154871 Determining If You Are Eligible for No-Charge Technical Support


WORKAROUND

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

-OR-

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          : 
Version           : WINDOWS:3.0
Platform          : WINDOWS 
Issue type        : kbbug

Last Reviewed: July 2, 1999