Microsoft KB Archive/307601

= Unable to Allocate LU 6.2 Sessions Using Dependent APPC LUs =

Article ID: 307601

Article Last Modified on 2/21/2007

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APPLIES TO


 * Microsoft SNA Server 3.0 Service Pack 4
 * Microsoft SNA Server 4.0
 * Microsoft Host Integration Server 2000 Standard Edition

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This article was previously published under Q307601



SYMPTOMS
Advanced Program-to-Program Communications (APPC) or Common Programming Interface for Communications (CPI-C) applications may be unable to allocate LU 6.2 sessions. This typically occurs after the applications have been functioning normally for a long period of time.

This problem only occurs if the SNA Server or Host Integration Server (HIS) 2000 systems are using dependent APPC LUs for communications with the host system.

The exact symptoms experienced by the end users of the APPC or CPI-C applications may vary depending on the application, but the following errors are likely to be returned by the underlying SNA Server/HIS 2000 APPC and CPI-C APIs:

APPC

Primary Return Code: 0003 (AP_ALLOCATION_ERROR)

Secondary Return Code: 00000005 (AP_ALLOCATION_FAILURE_RETRY)

CPI-C

Error 20 (CM_PRODUCT_SPECIFIC_ERROR)

-or-

Error 24 (CM_PROGRAM_PARAMETER_CHECK)



CAUSE
The SNA Server service gets into a state where it rejects solicited BINDs from the host, which leads to the APPC or CPI-C allocation failures. The following problems have been identified:
 * An internal variable could become negative if the SNA Server/HIS 2000 configuration is very large.
 * The SNA Server service does not correctly process a BIND when the host system responds to an INIT-SELF request with a NOTIFY ILU/TLU (Initiating LU/Terminating LU) notification of a procedure error.



SNA Server
A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Microsoft SNA Server version 4.0 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix should have the following file attributes or later:

NOTE: Because of file dependencies, the most recent fix that contains the preceding files may also contain additional files.

Host Integration Server 2000
To resolve this problem, obtain the latest service pack for Host Integration Server 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

328152 How to Obtain the Latest Host Integration Server 2000 Service Pack



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Host Integration Server 2000 Service Pack 1.



MORE INFORMATION
Note that the APPC and CPI-C errors described in the &quot;Symptoms&quot; section are common errors that can also occur for reasons other than the ones discussed in this article.

SNA Server and HIS 2000 systems that meet the following criteria may be susceptible to the problem described in this article:
 * Dependent APPC LUs used for LU 6.2 sessions.
 * Supports Dynamic Remote APPC LU Definition is enabled in the connection properties for the configured host connections.
 * SNA configurations that are very large. This would include configurations that contain large numbers of LUs (APPC, 3270, LUA) and/or host connections.

The following Microsoft Knowledge Base articles describe other problems related to dependent APPC LUs or the use of dynamic remote APPC LUs that can cause similar symptoms:

307520 Dynamic Remote LUs May Lead to Allocation Failures

281507 Dependent LU Version 6.2 Session Requests May Hang If Default Pool Is Used

259149 SNA Server Selects Bad Dependent APPC LU from Default Pool

245487 APPC Program Never Retries New Local LU From Pool

Additional query words: HIS 2000

Keywords: kbbug kbfix kbhostintegserv2000presp1fix kbhostintegserv2000sp1fix KB307601

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