Microsoft KB Archive/330328

= SNA Server Does Not Process Data That Is Received from the PVI Interface =

Article ID: 330328

Article Last Modified on 10/6/2005

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APPLIES TO


 * Microsoft SNA Server 4.0
 * Microsoft SNA Server 4.0 Service Pack 1
 * Microsoft SNA Server 4.0 Service Pack 2
 * Microsoft SNA Server 4.0 Service Pack 3
 * Microsoft SNA Server 4.0 Service Pack 4
 * Microsoft Host Integration Server 2000 Standard Edition
 * Microsoft Host Integration Server 2000 Service Pack 1

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This article was previously published under Q330328





SYMPTOMS
An application that is written for the Advanced Program-to-Program Communication (APPC) interface may stop responding intermittently.



CAUSE
In the sample that is discussed in this article, the problem is caused by an incoming LUSTAT negative response. The most significant bit of the sequence number is set in error.



SNA 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 SNA service pack that contains this fix.

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 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.    Date         Time      Version            Size    File name -- 29-Oct-2002 13:45     4.0.0.606       468,864    Snaservr.exe 29-Oct-2002 13:45     4.0.0.606       935,344    Trcservr.exe NOTE: Because of file dependencies, the most recent fix that contains the above files may also contain additional files.

Host Integration Server 2000

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 SNA 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 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. Date        Time   Version            Size    File name -- 08-Nov-2002 18:08  5.0.0.900       471,312    Snaservr.exe 08-Nov-2002 18:08  5.0.0.900     1,024,272    Trcservr.exe NOTE: Because of file dependencies, the most recent fix that contains the above files may also contain additional files.



WORKAROUND
You may be able to work around this problem by enhancing the &quot;Minimum Contention Winner Session Limit&quot; for outgoing conversations in the &quot;Limit&quot; section of the appropriate APPC Mode settings.

If no Contention Winner Sessions are available, SNA Server queries the remote system to find out if it is permitted to open a Bracket. This is completed by sending a LUSTAT request with the Begin Bracket Bit set. This eventually causes the error when the negative response is returned. This scenario does not occur if enough Contention Winner Sessions are available. SNA Server can then open a session immediately instead of prompting the remote system, thereby avoiding the problem.



STATUS
Microsoft has confirmed that this is a problem in Microsoft SNA Server version 4.0, all Service Packs and Host Integration Server 2000, all Service Packs.



MORE INFORMATION
When SNA Server Data Link Traces are enabled, an output similar to the following may appear: DLC  --- 13:50:29.0144 DLC  01020101->04160000 DLC DATA DLC                     DAF:02 OAF:04 ODAI:off Normal DLC                     LUSTAT RQD DFC FI BC EC DR1 QR  BB DLC DLC   Header  at address 013154C0, 1 elements DLC  1E010000 00002C00 020483EA 01002A01     <......,...c...*.> DLC DLC   Element at address 01D0A448, start 10, end 17 DLC  4B828004 00060000                       

DLC  --- 13:50:29.0191 DLC  04160000->01020101 DLC DATA DLC                     DAF:04 OAF:02 ODAI:off Normal DLC                     LUSTAT -RSP DFC FI SD BC EC DR1 QR DLC DLC   Header  at address 01315CAC, 1 elements DLC  04000004 10112C00 040283EA 0100F401     <......,...c...4.> DLC                        ^^^^ DLC   Element at address 01D0AB20, start 10, end 17 DLC  CF920008 14000004                       <.k...... > Notice that the LUSTAT has responded with a negative response. However, view the sequence number that is indicated by ^^^^, which is 83EA. The first significant bit is set. According to IBM's Systems Network Architecture Formats Guide, Document Number GA27-3136, the LUSTAT Request unit, Bytes 4-5 indicate in Note C: Low-order 15 bits of the SNF in the BB request that is being responded to. The high-order bit identifies the sender of the BB request (0 = secondary, 1 = primary). Because the LUSTAT request has not been sent by the primary SNA Server, processing of later conversation data for this session stops.

Additional query words: HIS 2000

Keywords: kbbug kbfix kbqfe KB330328

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