Microsoft KB Archive/259205

= APPC TP_STARTED does not verify local LU alias by default in Host Integration Server =

Article ID: 259205

Article Last Modified on 12/4/2007

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APPLIES TO


 * Microsoft Host Integration Server 2000 Standard Edition
 * Microsoft Host Integration Server 2004 Standard Edition

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This article was previously published under Q259205



SUMMARY
When you use Host Integration Server, an APPC application receives an AP_OK return code when it calls TP_STARTED with an invalid local APPC LU alias. However, the subsequent [MC_]ALLOCATE call does not succeed and you receive the following error message:

primary_rc = 0xF004 (AP_COMM_SUBSYSTEM_NOT_LOADED) secondary_rc = x020000F0

Unlike previous versions of SNA Server, Host Integration Server defers the client-server resource location until the APPC application issues the [MC_]ALLOCATE request when a local LU is provided to TP_STARTED. This change has been implemented in Host Integration Server to improve client-server resource location and load-balancing support. However, you can still configure a registry parameter to revert to the previous behavior in earlier versions of SNA Server.

For additional information about the AP_COMM_SUBSYSTEM_NOT_LOADED secondary return codes, click the article number below to view the article in the Microsoft Knowledge Base:

148359 SNA Server APPC Error: F004 AP_COMM_SUBSYSTEM_NOT_LOADED



MORE INFORMATION
By default, when an APPC application provides a local LU alias to the TP_STARTED call, Host Integration Server no longer verifies that the local LU has been configured. Instead, the APPC application now contacts the Host Integration Server when the [MC_]ALLOCATE request is issued to improve resource location and load-balancing support.

This change has a side effect for APPC applications that require two-phase commit support (if an APPC application issues TP_STARTED with syncpoint_rqd = AP_YES, and [MC_]ALLOCATE with sync_level = AP_SYNCPT). By default, such applications cannot retrieve a valid Logical Unit of Work ID (luw_id) until after the [MC_]ALLOCATE request is issued. In other words, such applications should not call TP_STARTED followed by GET_TP_PROPERTIES to retrieve the luw_id until after the [MC_]ALLOCATE request is issued.

However, to disable this behavior and enforce local LU alias verification for TP_STARTED, or to receive a valid luw_id immediately after calling TP_STARTED, you can configure the following registry parameter:

GenerateLUWIDonTPSTARTED: REG_SZ: YES

Find this parameter in the following locations:  On the computer running Host Integration Server or on the Admin client:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SnaBase\Parameters\Client\

 On the Host Integration Server end-user client:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SnaBase\Parameters\Client\



NOTE: Unlike SNA Server, Host Integration Server does not support the LUWIDSUP registry entry. Instead, this registry entry has been replaced with GenerateLUWIDonTPSTARTED.

Also, the GetAPPCReturnCode function has been updated to return the following error message when F004/020000F0 occurs:

Local LU not configured on an active Node. Either the Local LU has not been configured, or its Node is not started.

Therefore, any APPC application that uses the GetAPPCReturnCode function to convert the APPC error to a text string receives the correct error message.

Additional query words: HIS 2000 HIS2004

Keywords: kbinfo KB259205

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