Q194848: SDLC Connection Fails with Event 23, Qualifier X’002E’

Article: Q194848
Product(s): Microsoft SNA Server
Version(s): 4.0
Operating System(s): 
Keyword(s): 
Last Modified: 01-MAR-2002

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The information in this article applies to:

- Microsoft SNA Server, version 4.0 
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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 <connection name> using Link Service <link service 
   name> 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.


RESOLUTION
==========

SNA Server 3.0
--------------

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

  Q184307 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.

1. Start Registry Editor (Regedt32.exe).

2. 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.

3. On the Edit menu, click Add Value, and then add the following registry
  value:

     Value Name: SDLCWriteTimeout
     Data Type:  REG_SZ
     Value:      <writetimeout>

     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.

4. On the Edit menu, click Add Value, and then add the following registry
  value:

     Value Name: SDLCWriteRetries
     Data Type:  REG_SZ
     Value:      <writeretries>

     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.

5. Quit Registry Editor.

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.

Additional query words:

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Keywords          :  
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ400
Version           : :4.0
Issue type        : kbbug
Solution Type     : kbfix

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