After SDLC Outage, SNA Server Takes 5-10 Seconds to Recover (216711)

SYMPTOMS

IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

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, click the following article number to view the article in the Microsoft Knowledge Base:

215838 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, 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

MORE INFORMATION

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
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.