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FIX: The IP-DLC link service incorrectly sends a NOTIFY Request Unit before it sends the ACTLU +RSP Response Unit when dependent logical units (LUs) are available to be used

SYMPTOMS
Consider the following scenario:
  • You have a computer that is running Microsoft Host Integration Server 2004.
  • This computer uses the IP-DLC link service to communicate with an IBM mainframe.
In this scenario, the IP-DLC link service may send a NOTIFY Request Unit (NOTIFY RU) to an IBM mainframe before it sends the ACTLU +RSP Response Unit (ACTLU +RSP RU) to the mainframe. This action is a violation of the IBM SNA protocol that is used when dependent logical units (LUs) such as 3270 LUs are available to be used.

Note This issue also applies to Microsoft Host Integration Server 2006.
RESOLUTION

Host Integration Server 2006

To resolve this problem, obtain the latest service pack for Host Integration Server 2006. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
979497 How to obtain the latest Host Integration Server 2006 service pack

Host Integration Server 2004

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. 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 Web site: 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 Microsoft Host Integration Server 2004 installed to apply this hotfix.

Restart requirement

You must restart the Host Integration Server computer after you install this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later) 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 tool in Control Panel.
File nameFile versionFile sizeDateTimePlatformSP requirement
Snaipdlc.dll6.0.2118.0969,72825-Jun-200821:02x86SP1
Trcipdlc.dll6.0.2118.02,956,80025-Jun-200821:02x86SP1
Note Because of file dependencies, the most recent hotfix that contains these files may also contain additional files.

Microsoft Host Integration Server 2004 SP1

A hotfix is currently not available for Microsoft Host Integration Server 2004 SP1.
STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
MORE INFORMATION
After you apply this update, the IP-DLC link service correctly sends the ACTLU +RSP RU before it sends the NOTIFY RU to the IBM mainframe.

The following excerpt from an IP-DLC link service message trace shows the NOTIFY RU being sent to the IBM mainframe before the ACTLU +RSP RU. The traces were captured by using the SNA Trace utility (Snatrace.exe) to enable the Data Link Control and Level 2 Messages trace options for the SNAIP1 link service on a Host Integration Server computer.

The Data Link Control message trace shows the ACTLU +RSP RU and the NOTIFY RU in the following order:
DLC   03020101->01160001 DLC DATA     DLC                      DAF:00 OAF:02 ODAI:off Exp.   DLC                      ACTLU  +RSP SC  FI BC EC DR1 DLC   DLC   ---- Header at address 010142E0, 1 elements ----DLC   04010007 10002D00 00028E4B 0100041D     <......-....K....>DLC   DLC   ---- Element at address 01A026D0, start 10, end 28 ----DLC   EB80000D 02010085 8000000C 06010001     <.......e........>DLC   000000                                  <...             >DLC   03020101->01160001 DLC DATA     DLC                      DAF:00 OAF:02 ODAI:off Normal DLC                      NOTIFY RQD FMD FI BC EC DR1 DLC   DLC   ---- Header at address 01014244, 1 elements ----DLC   02020000 00002C00 00020000 0100041D     <......,.........>DLC   DLC   ---- Element at address 01A04230, start 10, end 23 ----DLC   0B800081 06200C06 01000100 0000         <...a. ........  >
The Level 2 Messages section of the traces has the ACTLU +RSP RU and the NOTIFY RU in the following order. This is the order in which they are sent to the IBM mainframe. The following data includes the NOTIFY RU:
IHV    UDP data => 10.24.192.78 (port 12001)                   IHV        DSAP=04, SSAP=04, CTRL=03 (UI) CMD, LEN=157             IHV        040403c6 00801100 0a010000 00d00000                     IHV        00000000 00ff0016 ffc1e900 012af330                     IHV        00000500 00007200 0003475c 00000400                     IHV        0000000c 0008a30b 90813005 02ff0003                     IHV        d0000004 22f0f0f6 00170ee4 e2c1c1f1                     IHV        4bd3f5f0 f8f8f9f1 f8c274b1 54ff6100                     IHV        01080100 280268f1 c9000033 15000016                     IHV        2c000002 00000b80 00810620 0c060100                     IHV        01000000 1960d13f a0c9a6b3 58670ee4                     IHV        e2c1c1f1 4bd3f5f0 f8f8f9f1 f8       
The following data includes the ACTLU +RSP RU:
IHV    UDP data => 10.24.192.78 (port 12001)                       IHV        DSAP=04, SSAP=04, CTRL=03 (UI) CMD, LEN=162             IHV        040403c6 00801100 0a010000 00d00000                     IHV        00000000 00ff0016 ffc1e900 012af330                     IHV        00000500 00007700 0003ba5c 00000500                     IHV        0000000c 0008a30b 90813005 02ff0003                     IHV        d0000004 22f0f0f6 00170ee4 e2c1c1f1                     IHV        4bd3f5f0 f8f8f9f1 f8c274b1 54ff6100                     IHV        01080100 2f0268f1 c9000038 1500001b                     IHV        2d000002 8e4beb80 000d0201 00858000                     IHV        000c0601 00010000 201960d1 3fa0c9a6                     IHV        b358670e e4e2c1c1 f14bd3f5 f0f8f8f9                     IHV        f1f8           
You can use a network trace utility such as Network Monitor to capture the data that is sent between the Host Integration Server computer and the IBM mainframe to confirm that the order of the ACTLU +RSP RU and the NOTIFY RU is as shown in this trace data.

The following table shows the expected SNA data flow that occurs when a dependent LU, such as a 3270 display LU, is available to be used.
Host Integration ServerDirection of SNA Data FlowIBM Mainframe
<-ACTLU
ACTLU +RSP->
NOTIFY(SLU Disabled)->
<-NOTIFY +RSP
When a user tries to make a 3270 session available to be used, the data flow continues as follows.
NOTIFY(SLU Enabled)->
<-NOTIFY +RSP
At this point, the 3270 session is available to be used, and the user typically receives a VTAM USSMSG 10 sign-on screen or another application screen.

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684Description of the standard terminology that is used to describe Microsoft software updates
Properties

Article ID: 954897 - Last Review: 10/08/2011 06:13:00 - Revision: 3.0

  • Microsoft Host Integration Server 2004 Enterprise Edition
  • Microsoft Host Integration Server 2004 Standard Edition
  • Microsoft Host Integration Server 2004 Service Pack 1
  • Microsoft Host Integration Server 2006 Enterprise Edition
  • Microsoft Host Integration Server 2006
  • kbautohotfix kbexpertiseadvanced kbbug kbfix kbqfe KB954897
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