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Q233373: CPIC App No Longer Limited to Single Local APPC LU

Article: Q233373
Product(s): Microsoft SNA Server
Version(s): WINDOWS:4.0,4.0SP1,4.0SP2
Operating System(s): 
Keyword(s): kbsna400sp3fix sna4 kbsna400sp1 kbsna400sp2
Last Modified: 08-MAY-2002

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The information in this article applies to:

- Microsoft SNA Server, versions 4.0, 4.0SP1, 4.0SP2 
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SYMPTOMS
========

The SNA Server CPIC interface (Wcpic32.dll) is designed to use a single Local
APPC LU for all conversations initiated by a CPIC application. This behavior is
described in the following Knowledge Base article:

  Q181123 CPIC Application Limited to Single Local APPC LU

Note that this behavior prevents a CPIC application from making use of different
pooled Local APPC LUs to reach one or more Remote APPC LUs residing on one or
more remote systems. While this continues to be the default behavior for SNA
Server 2.0, 2.1, 2.11, 3.0, and 4.0 (all service pack levels), an update to SNA
Server 4.0 Service Pack 2 (SP2) is now available that implements a new registry
parameter to allow a CPIC application to use multiple Local APPC LUs. See the
"More Information" section for more details.

RESOLUTION
==========

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


STATUS
======

Microsoft has confirmed this to be a problem in Microsoft SNA Server version
4.0, 4.0 SP1, and 4.0 SP2. This problem was first corrected in SNA Server
version 4.0 Service Pack 3.

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

After you apply the updated Wcpic32.dll and configure the GETNEWTPID registry
entry (as defined below), a CPIC application can allocate conversations using
different Local APPC LUs. However, note the following behavior:

- The CPIC application needs to call CMINIT (Initialize_Conversation) prior to
  calling CMALLC (Allocate) to receive a new Local APPC LU. If the CPIC
  application only calls CMINIT once, followed by two or more CMALLC requests,
  only one Local APPC LU is used for all conversations.

- Even when calling CMINIT more than once, a CPIC application may still receive
  the same Local APPC LU for multiple conversations. There is not any
  "balancing" of conversation use across different Local APPC LUs from a CPIC
  application.

- A CPIC application still tends to get conversations through one SNA Server. A
  single CPIC application doesn't "balance" conversation requests across
  different SNA Servers.

This update is intended for SNA Servers or SNA Windows NT client computers
running SNA 4.0 SP2. This update should be applied to any computers that support
CPIC applications that require access through more than one Local APPC LU. After
the update is applied, add the following registry key on the computer:

  HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/SnaBase/
  Parameters/Client/

  GETNEWTPID: REG_SZ: YES

The presence of GETNEWTPID under this registry key enables this new behavior for
CPIC applications.

Additional query words:

======================================================================
Keywords          : kbsna400sp3fix sna4 kbsna400sp1 kbsna400sp2 
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ400
Version           : WINDOWS:4.0,4.0SP1,4.0SP2
Issue type        : kbbug
Solution Type     : kbfix

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