Users May Fail to Reconnect to Dynamically Defined Dependent LUs (286813)


The information in this article applies to:

  • Microsoft Host Integration Server 2000
  • Microsoft SNA Server 4.0 SP4
This article was previously published under Q286813

SYMPTOMS

Users who connect to a mainframe by using Dynamically Defined Dependent LUs (DDDLUs) may not be able to reconnect to the mainframe after they disconnect. SNA Manager displays the failing LUs with a status of Available, but the LUs are no longer defined on the mainframe because they were dynamically deleted when the user disconnected the session.

CAUSE

When you use DDDLUs, SNA Server and Host Integration Server (HIS) 2000 send a Network Management Vector Transport (NMVT) Power-Off Response Unit (RU) to the host when a session is closed (terminated). SNA Server and HIS 2000 then expect to receive a Deactivate LU (DACTLU) RU from the host. The problem described here occurs if the host does not send a DACTLU in response to the NMVT Power-Off RU.

RESOLUTION

SNA Server 4.0

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:

File nameDateTime
Snaservr.exe12/05/200012:00PM

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

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

File nameDateTime
Snaservr.exe12/05/200012:00PM

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

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

The following shows a typical sequence that occurs when a dynamically defined LU is closed (terminated):

ClientSNA Server/HIS 2000Host
Close SSCP ->
TRMSLF ->
NMVT(Power-Off) ->
<- UNBIND
UNBIND +RSP ->
<- TRMSLF +RSP
<- NMVT +RSP
<- DACTLU
DACTLU +RSP ->


In the failing case described in this article, the host does not send a DACTLU to the SNA Server or HIS 2000.

After you apply the update, SNA Server and Host Integration Server will issue a new NMVT Power-On RU when they receive an OPEN SSCP Request (new session request) for a DDDLU, even if a DACTLU was never received when the LU was closed. The NMVT Power-On RU causes the mainframe to dynamically create the requested LU, so that it is available for use.

For additional information on SNA Server, Host Integration Server, and DDDLUs, click the article numbers below to view the articles in the Microsoft Knowledge Base:

161492 INFO: LU Session Activation Using Dynamically Defined Dependent

164592 Dynamically Defined Dependent LU Support for LUA LUs

276453 Dynamically Defined Dependent LU Support for Printer LUs

276481 SNA Server Does Not Send LU Name in NMVT for DDDLU

276196 NMVT Power Off Now Supported in SNA Server

Modification Type:MinorLast Reviewed:10/6/2005
Keywords:kbbug kbfix kbHostIntegServ2000preSP1fix kbHostIntegServ2000SP1fix KB286813
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