Microsoft KB Archive/161775

= Problem Starting Two Non-Queued TPs Simultaneously on Win3.x =

Article ID: 161775

Article Last Modified on 10/23/2003

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APPLIES TO


 * Microsoft SNA Server 2.1
 * Microsoft SNA Server 3.0

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This article was previously published under Q161775





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:  Two instances of the program are started. The first program issues a RECEIVE_ALLOCATE that completes after 20 or more seconds, and normal data flow occurs. 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. The computer running SNA Server may report the following events in the Windows NT Application event viewer:

Event 60

Failed to invoke APPC TP, 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=.



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 KB161775

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