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Q128245: CPIC/APPC Program May Hang Opening a Dependent APPC Session

Article: Q128245
Product(s): Microsoft SNA Server
Version(s): WINDOWS:2.0,2.1,2.11
Operating System(s): 
Keyword(s): 
Last Modified: 13-JUN-2001

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The information in this article applies to:

- Microsoft SNA Server, versions 2.0, 2.1, 2.11, on platform(s):
   - the operating system: Microsoft Windows NT 
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SYMPTOMS
========

Under SNA Server 2.0 or 2.1, when a CPIC or APPC application allocates a
dependent LU6.2 session where the dependent APPC LU is defined in SNA Server
Admin to be a "Member of Default Outgoing Local APPC LU Pool", the allocate
request may hang. Within an APPC application, the call to [MC_]ALLOCATE may not
return. Within a CPIC application, the call to CMINIT may not return (since CPIC
runs over APPC, the underlying APPC [MC_]ALLOCATE hangs).

CAUSE
=====

SNA Server 2.0 and 2.1 do not correctly implement pooling of dependent APPC
LU's, however, the SNA Server Admin program does not prevent it. The problem
doesn't occur if independent APPC LU's are configured to be a member of the
default outgoing APPC LU pool.

With dependent APPC LU's, SNA Server may have allocated the dependent APPC LU/LU
session to another APPC or CPIC application. If a second APPC or CPIC
application attempts to open the same dependent APPC LU (which can occur if a
dependent APPC LU is configured to be a member of the default APPC LU pool), the
second application's [MC_]ALLOCATE call will hang until the session becomes
available.


RESOLUTION
==========

To solve the problem on SNA Server 2.0 or 2.1, each CPIC or APPC application
must use a unique dependent Local APPC LU.

For an APPC application, the application must be predefined to use a specific
dependent Local APPC LU alias. If the Local LU alias is left blank, the default
Local APPC LU can be associated to a user or group within the "Users and Groups"
window of SNA Server Admin.

For a CPIC application, the Local APPC LU alias must be preset within SNA Server
by either:

- Defaulting the user/group to use a specific Local APPC LU alias:

  Within the "Users and Groups" window of SNA Admin, the user or group record
  can be configured with a default Local and Remote APPC LU aliases.

-or-

- Defaulting the workstation to use a specific Local APPC LU alias:

  The SNA Server client software can be defined with a default Local APPC LU
  alias, as described in the CPI-C API section of Appendix C in the SNA Server
  Reference Guide:

  Windows NT clients (within the Registry):

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

           application: REG_SZ: localLUalias

  Win 3.x clients (within WIN.INI) or OS/2 clients (within SNA.INI):

           [ApplicationName]
           APPCLLU=localLUalias

  where application is the name of the CPIC application (without the .EXE
  extension).

STATUS
======

This problem is fixed in SNA Server 2.11. The fix involves changes to the server
and the client software, so both ends must be updated to SNA Server 2.11.

Additional query words: prodsna 2.00 2.10 2.11 3.50 allocate

======================================================================
Keywords          :  
Technology        : kbAudDeveloper kbSNAServSearch
Version           : WINDOWS:2.0,2.1,2.11
Issue type        : kbbug
Solution Type     : kbfix

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

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