Microsoft KB Archive/166875

= 5250 Emulator Won't Connect Even Though Sessions Are Available =

Article ID: 166875

Article Last Modified on 2/20/2004

-

APPLIES TO


 * Microsoft SNA Server 3.0
 * Microsoft SNA Server 3.0 Service Pack 4

-



This article was previously published under Q166875



IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry



SYMPTOMS
When connecting to an AS/400, the 5250 applet shows Not Connected in the lower left corner. SNA Server shows that there are sessions available for the LU-LU pair the 5250 applet is attempting to use. However, some of these LUs on the AS/400 are in an Active - Detached state, thereby preventing the request for conversation from succeeding. The same thing will happen with other 5250 emulators. However, the message displayed in the emulator may be different.

NOTE: There are various situations in which you might see a Not Connected 5250 status. This article documents one possible situation. For other possible situations, see the following Microsoft Knowledge Base article:

150796 5250 Emulator Displays a BlackScreen Then Disconnects



CAUSE
The exact cause of why the AS/400 sometimes shows sessions in an Active - Detached state is unknown.



WORKAROUND
To work around this problem, apply the fix referenced below, and then edit the registry as follows.

NOTE: You must first apply the fix referenced below before editing the registry.

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.  Start Registry Editor (Regedt32.exe or Regedit.exe, as appropriate for your version of Windows NT).  Go to the following key in the registry: HKEY_LOCAL_ MACHINE\SYSTEM\CurrentControlSet\Services\SnaServr\ Parameters  On the Edit menu, click Add Value and use the following entry:

Value Name: SessionLimitMargin

Data Type: REG_SZ

This registry entry artificially lowers the number of post cnos negotiation by the value specified. Therefore, if the negotiated session limit for an LU-LU-MODE triplet is 8 and SessionLimitMargin is 2, the SNA Server service node will only start 6 sessions on the triplet. Exit Registry Editor.

This will work around the problem where SNA Server thinks it has sessions available and the AS/400 does not.

<div class="status_section">

STATUS
Microsoft has confirmed this to be a problem in SNA Server versions 2.11 and 3.0. This problem was corrected in the latest SNA Server version 3.0 U.S. Service Pack. For information on obtaining this Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

<div class="moreinformation_section">

MORE INFORMATION
The following will be seen in an SNA Server DLC trace:

The SNA Server service, thinking it has sessions available for a conversation request, sends an Attach (02ff) for conversation to the AS/400: <pre class="fixed_text">  DLC    -- 22:00:54.97 DLC   01020601->04160005 DLC DATA DLC                      DAF:36 OAF:01 ODAI:off Normal DLC                      RQE FMD FI BC EC DR1 PI CD   DLC DLC    Header  at address 00CC45EC, 1 elements DLC   0B05537E 324F2C00 36010001 01001121     <..S~2O,.6......!> DLC DLC    Element at address 011C68C8, start 10, end 233 DLC   0B91203F 0502FF18 03D00040 0430F0F0     <.j ?.......@.000> DLC   F50F0402 D7C3E209 014AB1D6 5ACABB72     <5...PCS..J.OZ..r>   DLC    8A160DC1 D7D7D54B D4E2E2D5 C1E2F1F6     <...APPNKMSSNAS16> DLC   54310016 0A040001 00080000 00000000     <T1..............> DLC   0001009E 12F5009A 12E20096 12A02000     <.....5...S.o.. .>  DLC    05100100 000023D9 E8C1D5C1 D7D7C1F1     <......#RYANAPPA1> DLC   40F3F1F9 F74040C3 F2404040 40000000     <@3197@@C2@@@@...> DLC   00000000 00000000 000026C4 E4E2C200     <..........&DUSB.> DLC   F6F9F740 F0F3F740 40404040 40404040     <697@037@@@@@@@@@> DLC   40404040 40404040 40E7F900 00000000     <@@@@@@@@@X9.....> DLC   41C10000 00004040 40404040 4040D7C3     <AA....@@@@@@@@PC> DLC   E2404040 40404040 D7C3E240 40404040     <S@@@@@@@PCS@@@@@> DLC   40402040 40404040 40404040 40404040     <@@ @@@@@@@@@@@@@> DLC   40404040 40404040 40404040 40404040     <@@@@@@@@@@@@@@@@> The AS/400 rejects the Attach with a 0846 0000 sense code promising the SNA Server the real error in a following message:

<pre class="fixed_text">  DLC    -- 22:00:56.66 DLC   04160005->01020601 DLC DATA DLC                      DAF:01 OAF:36 ODAI:off Normal DLC                      -RSP FMD SD BC EC DR1 DLC DLC    Header  at address 00CC6AE4, 1 elements DLC   0B05537E 324F2C00 01368000 0100BB00     <..S~2O,..6......> DLC DLC    Element at address 011C68C8, start 10, end 16 DLC   87900008 460000                         <g...F.. >

Here is the actual error from the AS/400:

<pre class="fixed_text">  DLC    -- 22:00:56.87 DLC   04160005->01020601 DLC DATA DLC                      DAF:01 OAF:36 ODAI:off Normal DLC                      RQE FMD FI BC EC DR1 PI CEB DLC DLC    Header  at address 00CC5FEC, 1 elements DLC   0B05537E 324F2C00 01360001 0100BB00     <..S~2O,..6......> DLC DLC    Element at address 011C5440, start 10, end 19 DLC   0B910107 07084B60 3100                  <.j....K`1. >

Primary Sense:  084B - Requested Resources Not Available Secondary Sense: 6031 - Transaction Program Not Available - Retry Available.

See SNA Formats Guide for the full text message.

The third-party products discussed here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.

Keywords: kbbug kbfix kbnetwork KB166875

-

[mailto:TECHNET@MICROSOFT.COM Send feedback to Microsoft]

© Microsoft Corporation. All rights reserved.