APPC Program Never Retries New Local LU From Pool (245487)


The information in this article applies to:

  • Microsoft SNA Server 4.0
  • Microsoft SNA Server 4.0 SP1
  • Microsoft SNA Server 4.0 SP2
  • Microsoft SNA Server 4.0 SP3
This article was previously published under Q245487

SYMPTOMS

If an APPC application supplies a blank Local APPC LU alias to TP_STARTED and calls [MC_]ALLOCATE multiple times using rtn_ctl = AP_WHEN_SESSION_FREE (where all sessions on a Local APPC LU become in use), [MC_]ALLOCATE requests may start to fail even though other Local APPC LUs from the default pool are available.

CAUSE

If an APPC application calls TP_STARTED once and receives a default Local APPC LU, all subsequent conversations that use that tp_id will use the same Local APPC LU alias. The APPC DLL (WAPPC32.dll) was not written to try a different default Local APPC LU in this case.

RESOLUTION

To resolve this problem, obtain the latest service pack for SNA Server 4.0. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack


WORKAROUND

An APPC application may work around this problem by calling TP_STARTED before every [MC_]ALLOCATE request (and by calling TP_ENDED after each conversation is not allocated).

STATUS

Microsoft has confirmed that this is a problem in Microsoft SNA Server version 4.0, 4.0 SP1, 4.0 SP2 and 4.0 SP3.

This problem was first corrected in SNA Server 4.0 Service Pack 4.

MORE INFORMATION

This specific problem won't occur with a CPIC application since CPIC doesn't support the equivalent of the APPC "AP_WHEN_SESSION_FREE" return control setting.
Modification Type:MajorLast Reviewed:11/24/2003
Keywords:kbbug kbfix kbQFE kbSNA400PreSP4fix kbSNA400sp4fix KB245487
©2003 Microsoft Corporation. All rights reserved.