DOCUMENT:Q161775  13-JUN-2001  [sna]
TITLE   :Problem Starting Two Non-Queued TPs Simultaneously on Win3.x
PRODUCT :Microsoft SNA Server
PROD/VER:WINDOWS:2.1,2.11
OPER/SYS:
KEYWORDS:kbnetwork

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft SNA Server, versions 2.1, 2.11 
-------------------------------------------------------------------------------


SYMPTOMS
========

If the host allocates two conversations at the same time, causing two instances
of a non-queued autostarted TP to be invoked on an SNA Server Windows 3.x
client, the following sequence of events occurs:

1. Two instances of the program are started.

2. The first program issues a RECEIVE_ALLOCATE that completes after 20 or more
   seconds, and normal data flow occurs.

3. The second program issues a RECEIVE_ALLOCATE that fails with the following
   error:

   primary_rc = 0x0002 (AP_STATE_CHECK)
   secondary_rc = 0x00000509 (AP_ALLOCATE_NOT_PENDING)

   When this occurs, the first program stops responding.

4. The computer running SNA Server may report the following events in the
   Windows NT Application event viewer:

   Event 60
   Failed to invoke APPC TP <value>, sense data = X'084C0000'
   AP_TRANS_PGM_NOT_AVAIL_NO_RETRY.

   Event 557
   DLOAD has timed out.

   Event 575
   Failed to Execute a program, RC=8 name=<value>.

If there is a 30-second delay between host attach requests, the problem doesn't
occur; both APPC TP's are invoked, and they run fine.

CAUSE
=====

This is a problem in the SNA Server 2.11 Windows 3.x client. If the Windows 3.x
client receives two dynamic load requests from two different servers within five
seconds, the SNA client (Wdmod.dll) may send the second acknowledgement
(RCV_ALLOC) message to the wrong server.

STATUS
======

Microsoft has confirmed this to be a problem in SNA Server version 2.1 and 2.11.
This problem was corrected in the latest SNA Server version 2.11 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


A supported fix is now available, but has not been fully regression- tested and
should be applied only to systems experiencing this specific problem. Unless you
are severely impacted by this specific problem, Microsoft recommends that you
wait for the next Service Pack that contains this fix. Contact Microsoft
Technical Support for more information.



Additional query words: prodsna

======================================================================
Keywords          : kbnetwork 
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ211 kbSNAServ210
Version           : WINDOWS:2.1,2.11

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2001.