FIX: APPC and CPI-C applications may stop responding if concurrent transaction requests are submitted when Host Integration Server 2009 connections are configured to support dynamic remote APPC logical units

View products that this article applies to.

Symptoms

Consider the following scenario:

You have an Advanced Program-to-Program Communications (APPC) application or a Common Programming Interface for Communications (CPI-C) application that submits transactions to a partner application by using Microsoft Host Integration Server 2009.
The Supports dynamic remote APPC LU definition option is enabled in the connection properties in SNA Manager.
There are no active APPC sessions on the SNA Server service at the time that the APPC application or the CPI-C application submits concurrent transaction requests.

In this scenario, the APPC application or the CPI-C application may stop responding (hang) as soon as the transactions are initiated.

Note This problem may also occur when you use Host Integration Server 2004 or Host Integration Server 2006.

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Cause

This problem occurs because the SNA Server service (Snaservr.exe) incorrectly handles the second APPC session request that is received while the first APPC session request is being processed. This problem occurs only when the Supports dynamic remote APPC LU definition option is enabled on the connection on which the APPC logical units (LUs) are defined in SNA Manager.

This problem does not occur if explicitly defined remote APPC LUs are being used.

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Resolution

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website:

http://support.microsoft.com/contactus/? ws=support

Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

You must have Host Integration Server 2009 installed to apply this hotfix.

Restart information

You do not have to restart the computer after you apply this hotfix.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

For all x86-based versions of Host Integration Server 2009

File name	File version	File size	Date	Time	Platform
Snaservr.exe	8.0.3776.2	679,760	14-Sep-2010	00:42	x86
Trcservr.exe	8.0.3776.2	920,912	14-Sep-2010	00:42	x86

For all x64-based versions of Host Integration Server 2009

File name	File version	File size	Date	Time	Platform
Snaservr.exe	8.0.3776.2	967,504	14-Sep-2010	00:44	x64
Trcservr.exe	8.0.3776.2	1,261,904	14-Sep-2010	00:44	x64

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Workaround

To work around this problem, disable the Supports dynamic remote APPC LU definition option in the connection properties in SNA Manager for the connections that use APPC LUs. By default, for connections that use the IP-DLC link service, the Supports dynamic remote APPC LU definition option is enabled.

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Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

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More Information

If dependent Local APPC LUs are being used in a scenario similar to the one described here, you will also have to use the SNACFG command-prompt utility to assign the remote APPC LUs to the IP-DLC "Host system" connection that the dependent Local APPC LUs are using.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

947858 FIX: Event 17 occurs when a mainframe application tries to invoke an APPC application over an IP-DLC connection by using a dependent LU 6.2 logical unit

If the remote APPC LUs are not manually assigned to the IP-DLC "Host system" connection by using Snacfg.exe, the SNA Server service will dynamically create remote APPC LUs for the APPC session requests. This occurs even though the remote APPC LUs are explicitly defined in the Host Integration Server configuration.

For more information about how to configure dependent local APPC LUs when you use the IP-DLC link service, click the following article number to view the article in the Microsoft Knowledge Base:

939193 How to set up the connection and the logical units for an APPC application when you use the IP-DLC link service in Host Integration Server 2006 together with dependent APPC logical units

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