Microsoft KB Archive/317642

= FIX: APPC/CPI-C Applications May Not Switch to an Active Connection =

Article ID: 317642

Article Last Modified on 10/6/2005

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APPLIES TO


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

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This article was previously published under Q317642



SYMPTOMS
An Advanced Program-to-Program Communications/Common Programming Interface for Communications (APPC/CPI-C) application that operates properly with one connection may stop responding (hang) when the application needs to switch to another connection in a Hot Backup or Load Balancing situation.



CAUSE
SNA Server 4.0 SP4 uses a new load balancing code that does not handle a &quot;lost locality message&quot; properly.



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:

  Date         Time    File name -  17-Dec-2001  15:35   Wappc32.dll

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:

  Date         Time    File name -  17-Dec-2001  15:35   Wappc32.dll

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
Microsoft added a &quot;last good server&quot; field to Host Integration Server 2000 and SNA Server 4.0 SP4 to prevent unnecessary retries to establish a conversation through an active connection. This field is not reset correctly during lost-locality processing, so the resource location code makes repeated attempts to use the non-existent connection.

If you enable Systems Network Architecture (SNA) Application internal tracing, the resulting trace may appear as follows: LU62CONN for tpcb 0x1472030 rcb 0x1472128 tpcb_destl is zero - use locality 3 for rcb not first pass open lu62 send non-directed open srci:0x0001 desti:0x0000 send to destl 3 from srcl 0 MangleLPIs in from an App XLPI 0004:00:0002->0004:00:0000 CLP 00:00->03:11 XLPI 0200:00:0002->0003:11:0000 CLP 00:00->03:11 O| XLPI 0200:00:0002->0003:11:0000 CLP 00:00->03:11 O| MHTYP:0x0001 MSGTYP:0x01 OPNQUAL:0x01 OPNTYP:0x24 NUMELT:0x02 L-table entry is not in use, LVAL=1 The last entry: L-table entry is not in use, LVAL=1 indicates the &quot;lost locality message&quot; that the application does not handle properly.

Additional query words: Snaservr sp1 sp2 sp3 sp4 1 2 3 4 service pack HIS 2000

Keywords: kbbug kbfix kbhostintegserv2000sp1fix kbsna400sp4 kbhis2000fix sna4 kbhostintegserv2000presp1fix kbsna400sp3 kbsna400sp2 kbsna400sp1 KB317642

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