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Q161190: TN3270 Error 520 When the Host Unbinds and Binds a Session

Article: Q161190
Product(s): Microsoft SNA Server
Version(s): WINDOWS:2.0,2.1,2.11,2.11 SP1
Operating System(s): 
Keyword(s): kbnetwork
Last Modified: 12-JUN-2001

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The information in this article applies to:

- Microsoft SNA Server, versions 2.0, 2.1, 2.11, 2.11 SP1 
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SYMPTOMS
========

The TN3270 client loses its session, receiving an error 520. The Application
Event Logs on the computer running SNA Server show an event 603 with the
following description:

  TN3270E Service Error 520

  Internal LU session state error in FirstInboundByteProcess.
  State error id - 2 (expected CONT,SND,RCV).
  Current state - LU-LU, SNDNXMT

The TN3270 Server traces show the following:

  >09/24 10:33:35.850 (+ smidgen )  Event=TEV_DataFromSNA
   Thread = 0x0000010B  Session = 0x00180478  Socket = 0x00000238
   VCB address=0x00180684
   verb_length=0x0044  verb=0x0052 (RUI)  opcode=0x8004 (WRITE)
   sid=0x000000A8  correlator=0x00180478  post_handle=0x00000150
   prim_rc=LUA_OK  sec_rc=LUA_SEC_RC_OK
   lu_norm    lua_data_length=0x00000000
   TH Only    efi=0  oadi=0  daf=00  oaf=00  snf=0002
   RH +RSP FMD fi=0   sdi=0  bci=1  eci=1  (Only)
   83 80 00    dr1=1  dr2=0  ri=0   qri=0  pi=0
               bbi=0  ebi=0  cdi=0  csi=0  edi=0  pdi=0

  >09/24 10:33:35.850 (+ smidgen )  Event=TEV_CRTOutboundWriteComplete
   Thread = 0x0000010B  Session = 0x00180478  Socket = 0x00000238
   State = OPER        InputState = IGNORE      OutputState = SNAREAD
   Toggle = LU-LU       LU State = SND         CanQueue = DATAPEND
   Bracket = INB         DTActive

  >09/24 10:33:35.860 (+ 10 msecs)  Event=TEV_LogicError
   FirstInboundByteProcess
   LUSessionStateConfused

CAUSE
=====

A session status flag in the TN3270 Server is not being reset when the host
unbinds and rebinds a session.

RESOLUTION
==========

To resolve this problem, obtain the hotfix mentioned below.

STATUS
======

Microsoft has confirmed this to be a problem in SNA Server versions 2.0, 2.1,
2.11, and 2.11 Service Pack 1. This problem was corrected in the latest
Microsoft SNA Server 2.11 U.S. Service Pack. 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


Additional query words: sp1 prodsna

======================================================================
Keywords          : kbnetwork 
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ200 kbSNAServ211 kbSNAServ210 kbSNAServ211SP1
Version           : WINDOWS:2.0,2.1,2.11,2.11 SP1
Issue type        : kbbug
Solution Type     : kbfix

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