Microsoft KB Archive/185630

= 3270 Sessions May Hang When Emulator Rejects Host Bind =

Article ID: 185630

Article Last Modified on 5/23/2003

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APPLIES TO


 * Microsoft SNA Server 3.0 Service Pack 2
 * Microsoft SNA Server 3.0 Service Pack 3
 * Microsoft SNA Server 4.0

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This article was previously published under Q185630



SYMPTOMS
3270 sessions may appear to stop responding occasionally if the 3270 Emulator rejects an application BIND that it receives from the host. In addition, the computer running SNA Server that the 3270 session is defined on may log the following message in the Windows NT Application Event Log:

  Event ID: 9 Source: SNA Server Description: (1117) A protocol error occurred due to a message sent by a 3270 emulator or link service

EXPLANATION A protocol error occurred due to a message sent by a 3270 emulator or link service.

SUBCODE INFORMATION X'1117' A 3270 emulator used by the following user caused an error, though the user's 3270 session was not interrupted:

Client Domain: Client User: LU name:       <3270 LU name> FMI Sense Code:

NOTE: The Event 9 message was enhanced in SNA Server 3.0 SP3 and SNA Server 4.0 to include the additional client, LU, and FMI Sense Code information shown here.

This particular problem only occurs with SNA Server versions 3.0 SP2, 3.0 SP3, and 4.0.



CAUSE
SNA Server occasionally discards OPEN PLU RSP ERROR messages it receives from 3270 emulators. When SNA Server discards this message, it fails to sends a BIND -RSP to the host for that particular session (for example, 3270 LU). This causes the session to stop responding because the host is waiting for a response to the application BIND that it sent for that session.



SNA Server 3.0
To resolve this problem, obtain the latest service pack for SNA Server version 3.0. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

184307 How to Obtain the Latest SNA Server Version 3.0 Service Pack

SNA Server 4.0
This problem has been corrected in the latest U.S. Service Pack for SNA Server version 4.0. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

  S E R V P A C K



STATUS
Microsoft has confirmed that this is a problem in SNA Server versions 3.0SP2, 3.0 SP3, and 4.0. This problem was first corrected in SNA Server 3.0 Service Pack 4.



MORE INFORMATION
Event 9 messages can occur for other reasons and do not usually cause the system to stop responding or drop 3270 sessions.

For additional information about Event 9 and Event 12 messages, please see the following article in the Microsoft Knowledge Base:

181121 Enhanced Event Logging for SNA Server Event 9, 12

When a user signs on to a host application (for example, TSO, IMS, and so forth), the host sends an application BIND to SNA Server. SNA Server sends this BIND to the emulator through the Function Management Interface (FMI) OPEN PLU REQUEST message. If the 3270 emulator/application rejects the BIND that it receives in the OPEN PLU REQUEST, it returns an OPEN PLU ERROR RESPONSE message. SNA Server is supposed to send a BIND -RSP to the host when it receives an OPEN PLU ERROR RESPONSE. This problem occurs when the SNA Server fails to send a BIND -RSP to the host when it receives an OPEN PLU ERROR RESPONSE.

The following is an excerpt of SNA Server Data Link Control and 3270 Message traces that capture the problem:

  DLC   01020201->04160000 DLC DATA DLC                     DAF:00 OAF:47 ODAI:off Normal DLC                     RQD FMD BC EC DR1 DLC DLC   Header  at address 0122DB90, 1 elements DLC  01000000 00012C00 0047008C 01000000 <......,..G......> DLC DLC   Element at address 0179CA4C, start 10, end 15 DLC  038000C9 D4E2                           <...IMS>

The user enters IMS to get to access IMS on the host.

  DLC   04160000->01020201 DLC DATA DLC                     DAF:47 OAF:01 ODAI:off Exp.   DLC                      BIND   RQD SC  FI BC EC DR1 DLC DLC   Header  at address 0122DD64, 1 elements DLC  01000000 00012D00 470144A9 01004E00     <......-.G.Dz..N.> DLC DLC   Element at address 0179CA4C, start 10, end 47 DLC  6B800031 010303B1 90308000 00888680  DLC  00020000 00000018 5018507F 000006D4 <........P.P...M>  DLC   C9C9D4E2 D400                           

The host sends a BIND for the IMS application.

  FMI   01026E03->33120000 OPEN  PLU  REQUEST FMI                     FMI  CredR:0 CredS:0 FMI FMI   Header  at address 0122DB90, 2 elements FMI  01020247 001A0000 0000008C 0100C100 <...G..........A.> FMI FMI   Element at address 0179D124, start 1, end 26 FMI  44434250 54323339 00202020 20202020      FMI  20202020 00000800 0200                  <    ......> FMI FMI   Element at address 0179CA4C, start 4, end 47 FMI  2D004701 44A96B80 00310103 03B19030     <-.G.Dzk..1.....0> FMI  80000088 86800002 00000000 00185018 <...hf.........P.> FMI  507F0000 06D4C9C9 D4E2D400               FMI

The BIND is sent to the 3270 emulator in this OPEN PLU REQUEST

  FMI   3312001A->01026E03 OPEN  PLU  RSP ERROR FMI                     FMI  Err1:0805 Err2:0000 Non-neg Bind FMI FMI   Header  at address 0122DB90, 0 elements FMI  03020247 001A0805 0000008C 0100C100 <...G..........A.>

The SNA Server does not send a BIND -RSP to the host after receiving this message. The 3270 session stops responding until the user ends the session.

Additional query words: hang hangs hung

Keywords: kbbug kbfix KB185630

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