Microsoft KB Archive/194848

= SDLC Connection Fails with Event 23, Qualifier X'002E' =

Article ID: 194848

Article Last Modified on 12/29/2003

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APPLIES TO


 * Microsoft SNA Server 4.0

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This article was previously published under Q194848



IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.



SYMPTOMS
When SNA Server and its synchronous data link control (SDLC) link service do not receive an acknowledgement for a transmitted Information Frame (I- Frame) from the underlying SDLC hardware (that is, SDLC Adapter), the following error will be logged in the Windows NT Application Event Log:

  Event ID: 23 Source: SDLC Link Service Description: Connection using Link Service  failed Qualifier = X'002E' The qualifer of X'002E' indicates that the Write Timeout Retry has been exceeded.



CAUSE
I-Frames should generally be acknowledged before the Write Timeout/Retry value of 15 seconds expires. However, it is not possible to change the Write Timeout and Write Retry Limit parameters in the event that a longer timeout is needed because these values are hardcoded.

These parameters were not originally designed to be configurable.



SNA Server 3.0
To resolve this problem, obtain the latest service pack for SNA Server version 3.0. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

184307 How to Obtain the Latest SNA Server Version 3.0 Service Pack

SNA Server 4.0
Microsoft has confirmed this to be a problem in SNA Server version 4.0 and 4.0 SP1. This problem was corrected in the latest SNA Server version 4.0 U.S. Service Pack. For information on obtaining this Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

  S E R V P A C K



STATUS
Microsoft has confirmed this to be a problem in SNA Server 2.11, 2.11 Service Pack 1, 2.11 Service Pack 2, 3.0, 3.0 Service Pack 1, 3.0 Service Pack 2, 3.0 Service Pack 3, 4.0, and 4.0 Service Pack 1. This problem was first corrected in SNA Server 3.0 Service Pack 4.



MORE INFORMATION
The Write Timeout value is set to 1,000 milliseconds and the Write Retry Limit is set to 15. These values cannot be changed. So, if an I-Frame is not acknowledged within 15 seconds from the time it was sent to the SDLC hardware, the error described above will be logged and the SDLC connection will drop to a Pending state while it attempts to re-establish the SDLC connection to the remote device.

After applying the hotfix above, the Write Timeout and Write Retry Limit parameters can be configured by setting the following registry parameters:

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.

 Start Registry Editor (Regedt32.exe). Locate the following key in the registry: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Snaservr \Parameters NOTE: The above registry key is one path; it has been wrapped for readability.  On the Edit menu, click Add Value, and then add the following registry value: <pre class="fixed_text">     Value Name: SDLCWriteTimeout Data Type: REG_SZ Value:

where: writetimeout can be from 1 to 65,535 milliseconds.

The default value for this entry is 1,000 milliseconds. If the entry does not exist, the default value will be used. </li>  On the Edit menu, click Add Value, and then add the following registry value: <pre class="fixed_text">     Value Name: SDLCWriteRetries Data Type: REG_SZ Value:

where: writeretries can be from 1 to 65535.

The default value for this entry is 15. If the entry does not exist, the default value will be used. </li> Quit Registry Editor.</li></ol>

For more information on these and other SDLC connection parameters, please refer to Open(LINK) Request message discussion in Chapter 4 of the SNA Device Interface Specification manual included with the SNA Server SDK.

Keywords: kbbug kbfix KB194848

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