After SDLC Outage, SNA Server Takes 5-10 Seconds to Recover

ID: Q216711

The information in this article applies to:

Microsoft SNA Server, versions 3.0, 3.0SP1, 3.0SP2, 3.0SP3, 4.0, 4.0SP1, 4.0SP2

SYMPTOMS

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.

After receiving an outage (connection failure) from the IBM SDLC link service, SNA Server takes from 5 to 10 seconds before posting a CLOSE(LINK), and subsequent new OPEN(LINK) to retry connection activation. During this time, the host may stop retrying the PU, and may set the PU to an inactive status, requiring manual host intervention to recover the SDLC connection.

CAUSE

SNA Server intentionally delays SDLC connection recovery to ensure that the SNA Server DACTPU reply has an opportunity to be sent by the link service to the host. However, in a certain customer environment, this 5 to 10 second delay exceeded the host's SDLC connection recovery time period.

RESOLUTION

SNA Server 4.0

To resolve this problem, obtain the latest service pack for SNA Server version 4.0. For additional information, please see the following article in the Microsoft Knowledge Base:

Q215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack

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

STATUS

Microsoft has confirmed this to be a problem in SNA Server 3.0 (SP1-SP3) and SNA Server 4.0 (SP1-SP2). This problem was first corrected in SNA Server version 3.0 Service Pack 4 and SNA Server version 4.0 Service Pack 3.

MORE INFORMATION

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. If you are running Windows NT, you should also update your Emergency Repair Disk (ERD).
After this hotfix is applied, the NoSDLCOutageTimer registry parameter must be added to eliminate the SDLC connection recovery period. Follow these steps to add this registry value:

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:


      Value Name: NoSDLCOutageTimer
      Data Type:  REG_SZ
      Value:      <any value> (the presence of the registry key enables support)

Quit Registry Editor.

Additional query words:

Keywords : sna3sp4fix sna4sp3fix
Version : WINDOWS:3.0,3.0SP1,3.0SP2,3.0SP3,4.0,4.0SP1,4.0SP2
Platform : WINDOWS
Issue type : kbbug