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Q193815: Improved APPC/CPIC Performance on SNA Client Computer

Article: Q193815
Product(s): Microsoft SNA Server
Version(s): WINDOWS:4.0,4.0 SP1
Operating System(s): 
Keyword(s): 
Last Modified: 22-OCT-2000

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The information in this article applies to:

- Microsoft SNA Server, versions 4.0, 4.0 SP1 
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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.

SUMMARY
=======

When an APPC application calls TP_ENDED (to end the last conversation) from an
SNA Server Windows NT or Windows 95 or Windows 98 client computer, the
underlying LAN session to the SNA Server is dropped. If the application
immediately calls TP_STARTED and [MC_]ALLOCATE to invoke a new conversation, a
new LAN session is established to the SNA Server, and the user is authenticated
again by the server. This can significantly reduce APPC application performance
if the program continuously starts, ends, and restarts new conversation
requests.

MORE INFORMATION
================

An update to Snadmod.dll for SNA Server 4.0 is available which improves
performance. Instead of closing a client-server connection immediately after the
last conversation ends, Snadmod.dll now waits a short period before it closes
the LAN connection. The idea is that if the application starts a new
conversation within this period, the snadmod.dll can avoid expensive logon
validations and resource allocations by reusing the existing connection. The
delay is configurable through the following registry parameter.

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).

SNA Server Windows NT Client
----------------------------

1. Apply the hotfix.

2. Start the Windows NT Registry Editor (Regedt32.exe) and find the following
  key:

  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SnaBase
      \Parameters\ 

3. Add the following entry to this key:

      Value Name: CloseTimeout
      Data Type: REG_DWORD
      Data (Decimal): <value>

  Where value is the number of seconds. If this entry is not specified, the
  CloseTimeout value internally defaults to 10 seconds.

SNA Server Windows 95 or Windows 98 Client
------------------------------------------

1. Apply the hotfix.

2. Start the Windows 95/98 Registry Editor (Regedit.exe) and find the following
  key:

  HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SnaBase
      \Parameters\ 

3. Add the following new DWORD value:

      CloseTimeout
      Value Data (Decimal): <value>

  Where value is the number of seconds. If this entry is not specified, the
  CloseTimeout value internally defaults to 10 seconds.

This update applies to any SNA Server Windows NT, Windows 95, or Windows 98
client which runs an APPC or CPIC application to connect through an SNA Server
running on a separate computer. The SNA Server does not need to be updated, and
can remain at SNA Server 4.0 or a prior release. If the application is running
on the server itself, it may still establish a LAN session to use resources
provided by another SNA Server in the subdomain. In this case, this update
should be applied to the server (that is, the computer where the application is
running).


RESOLUTION
==========

Microsoft has produced an update to SNA Server 4.0 which improves performance,
as described in this article. This update is in included 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


Additional query words:

======================================================================
Keywords          :  
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ400 kbSNAServ400SP1
Version           : WINDOWS:4.0,4.0 SP1
Issue type        : kbinfo

=============================================================================

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