Microsoft KB Archive/249820

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TP May Start Slowly When Using Dynamic Remote APPC LU Definition

Article ID: 249820

Article Last Modified on 10/21/2005


  • Microsoft SNA Server 4.0
  • Microsoft SNA Server 4.0 Service Pack 1
  • Microsoft SNA Server 4.0 Service Pack 2
  • Microsoft SNA Server 4.0 Service Pack 3

This article was previously published under Q249820

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


An APPC application may experience a slow response time when it is configured to use an SNA subdomain with multiple SNA Server computers if the Supports Dynamic Remote APPC LU Definition option is enabled on several computers.


If an APPC application specifies a Local LU Alias when calling TP_STARTED, the APPC interface incorrectly tries SNA Server computers that are configured to support dynamic remote APPC LU definition, even if those computers do not support the Local LU Alias being requested. Because additional time is spent connecting to those other servers, the opening of the application may be delayed.


To work around this issue, try one of the following:

If you are not using Supports Dynamic Remote APPC LU Definition, disable it by clicking to uncheck the Supports Dynamic Remote APPC LU Definition check box on the SNA Server computer(s).


Configure the LUWIDSUP=NO registry entry on the computer where the APPC program is running.

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.

On SNA Windows NT clients:


On SNA Windows 95 clients:


Setting this registry entry to NO defers resource allocation until an [MC_]ALLOCATE is issued. This causes WAPPC32 to issue the GetServerList with the Remote APPC LU alias only, and not the local. Therefore, the resource allocation proceeds correctly.


A supported feature that modifies the product's default behavior is now available from Microsoft, but it is only intended to modify the behavior that this article describes. Apply it only to systems that specifically require it. This feature may receive additional testing. Therefore, if the system is not severely affected by the lack of this feature, we recommend that you wait for the next Microsoft SNA server version 4.0 service pack that contains this feature.

To obtain this feature immediately, contact Microsoft Product Support Services. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

The English version of this feature should have the following file attributes or later:

SNABASE.EXE 01/24/00 08:09p

NOTE: Because of file dependencies, the most recent fix that contains the preceding files may also contain additional files.

NOTE: This hotfix is for the SNA Server. This update does not have to be applied to the SNA clients.

Keywords: KB249820