KB161190 - TN3270 Error 520 When the Host Unbinds and Binds a Session

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

TN3270 Error 520 When the Host Unbinds and Binds a Session

SYMPTOMS

CAUSE

RESOLUTION

STATUS