TN3270 Client's Session Drops (163578)


The information in this article applies to:

  • Microsoft SNA Server 2.11
  • Microsoft SNA Server 2.11 SP1
This article was previously published under Q163578

SYMPTOMS

When you are using a TN3270e client against the TN3270 service, the TN3270e client session drops.

CAUSE

The host had not yet sent a Change Direction (CD) indicator telling the TN3270 client that it had direction to send data.

RESOLUTION

To resolve this problem, obtain the hotfix mentioned below. In the hotfix, the TN3270 server discards all data received from a TN3270 emulator if the host has not yet sent a CD message.

STATUS

Microsoft has confirmed this to be a problem in Microsoft SNA Server versions 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

MORE INFORMATION

SNA Server sends the TN3270 service a message inbound from the host. A TN3270 trace shows the following (notice that there is no CD bit set): 
   FMI    ---------------------------------------------- 14:23:29.63
   FMI    01020E02->0B1D0001 FMI DATA
   FMI                       NO ACK reqd Key:312 Seq:309 BCI ECI CEI
   FMI                       BBIUI EBIUI
   FMI
   FMI    ---- Header  at address 00DA4620, 1 elements ----
   FMI    00050138 600E2C00 05010135 0100B100     <...8`.,....5....>
   FMI
   FMI    ---- Element at address 0129B000, start 4, end 23 ----
   FMI    2C000501 01350390 00F14011 F56F1D40     <,....5...1@.5o.@>
   FMI    1161F013                                <.a0.            >
The following is the TN3270 Service sending the same message to the client: 
   >06/12 14:23:29.645 (+ smidgen )  Event=TEV_DataToClient
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    LU-LU Data
    Number of bytes = 30

   >06/12 14:23:29.645 (+ smidgen )  Event=TEV_TCPSendIssued
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    Number of bytes = 30
    000000  0000 0100 f401 c111 086f 1d40 3c0a 5000  |....4.A..?. ..&.|
    000010  3c0c 3000 3c00 0000 1108 7013 ffef       |..............  |

   >06/12 14:23:29.645 (+ smidgen )  Event=TEV_CRTReadProcessed
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    State = OPER        InputState = IDLE        OutputState = TCPWRITE
    Toggle = LU-LU       LU State = RCV         CanQueue = YES
    Bracket = INB         DTActive

   >06/12 14:23:29.645 (+ smidgen )  Event=TEV_TCPSendCompleted
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    Bytes transferred = 30

   >06/12 14:23:29.645 (+ smidgen )  Event=TEV_DataToSNA
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    VCB address=0x0027775C
    verb_length=0x0044  verb=0x0052 (RUI)  opcode=0x8003 (READ)
    sid=0x00000001  correlator=0x00277598  post_handle=0x000001F8
    prim_rc=LUA_OK  sec_rc=LUA_SEC_RC_OK
    lua_max_length=0x00000800

   >06/12 14:23:29.655 (+ 10 msecs)  Event=TEV_DataFromSNA
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    VCB address=0x0027775C
    verb in progress -- opcode=0x8003 (READ)

   >06/12 14:23:29.655 (+ smidgen )  Event=TEV_CRTOutboundWriteComplete
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    State = OPER        InputState = IDLE        OutputState = SNAREAD
    Toggle = LU-LU       LU State = RCV         CanQueue = YES
    Bracket = INB         DTActive

   >06/12 14:23:29.655 (+ smidgen )  Event=TEV_DataFromSNAAsync
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    VCB address=0x0027775C
    verb_length=0x0044  verb=0x0052 (RUI)  opcode=0x8003 (READ)
    sid=0x00000001  correlator=0x00277598  post_handle=0x000001F8
    prim_rc=LUA_OK  sec_rc=LUA_SEC_RC_OK
    lu_norm    lua_data_length=0x0000000B
    lua_message_type=0x01 (LUA_MESSAGE_TYPE_LU_DATA)
    TH Only    efi=0  oadi=0  daf=05  oaf=01  snf=0135
    RH  REQ FMD fi=0   sdi=0  bci=1  eci=1  (Only)
    03 90 00    dr1=1  dr2=0  ri=1   qri=0  pi=0
                bbi=0  ebi=0  cdi=0  csi=0  edi=0  pdi=0
    000000  f14011f5 6f1d4011 61f013             *1 .5?. ./0.     *

   >06/12 14:23:29.655 (+ smidgen )  Event=TEV_DataToClient
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    LU-LU Data
    Number of bytes = 18

   >06/12 14:23:29.655 (+ smidgen )  Event=TEV_TCPSendIssued
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    Number of bytes = 18
    000000  0000 0100 f501 4011 f56f 1d40 1161 f013  |....5. .5?. ./0.|
    000010  ffef                                     |..              |

   >06/12 14:23:29.665 (+ 10 msecs)  Event=TEV_CRTReadProcessed
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    State = OPER        InputState = IDLE        OutputState = TCPWRITE
    Toggle = LU-LU       LU State = RCV         CanQueue = YES
    Bracket = INB         DTActive

   >06/12 14:23:29.665 (+ smidgen )  Event=TEV_TCPSendCompleted
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    Bytes transferred = 18

   >06/12 14:23:29.665 (+ smidgen )  Event=TEV_DataToSNA
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    VCB address=0x0027775C
    verb_length=0x0044  verb=0x0052 (RUI)  opcode=0x8003 (READ)
    sid=0x00000001  correlator=0x00277598  post_handle=0x000001F8
    prim_rc=LUA_OK  sec_rc=LUA_SEC_RC_OK
    lua_max_length=0x00000800

   >06/12 14:23:29.665 (+ smidgen )  Event=TEV_DataFromSNA
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    VCB address=0x0027775C
    verb in progress -- opcode=0x8003 (READ)

   >06/12 14:23:29.665 (+ smidgen )  Event=TEV_CRTOutboundWriteComplete
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    State = OPER        InputState = IDLE        OutputState = SNAREAD
    Toggle = LU-LU       LU State = RCV         CanQueue = YES
    Bracket = INB         DTActive

   >06/12 14:23:32.159 (+  2 secs )  Event=TEV_TCPRecvCompleted
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    Bytes returned = 10

The following is the client sending data to the TN3270 service when it does
not have direction to send:

   >06/12 14:23:32.159 (+ smidgen )  Event=TEV_DataFromClient
    Thread = 0x000000DC  Session = 0x00277598  Socket = 0x0000005C
    000000  0000 0100 e87d 61f0 ffef                 |....Y'/0..      |

The following is the TN3270 service rejecting the client's message:

   >06/12 14:23:32.179 (+ 20 msecs)  Event=TEV_LogicError
    InboundLULUData
    LUSessionStateConfused

   FMI    ---------------------------------------------- 14:23:32.25
   FMI    0B1D0001->01020502 CLOSE SSCP REQUEST
   FMI
   FMI    ---- Header  at address 00DA4620, 0 elements ----
   FMI    01010001 600E2C00 05010135 0100C800     <....`.,....5..H.>
   FMI    ---------------------------------------------- 14:23:32.26
   FMI    01020502->0B1D0001 CLOSE SSCP RSP OK
   FMI
   FMI    ---- Header  at address 00DA4620, 0 elements ----
   FMI    02010001 600E2C00 05010135 0100C800     <....`.,....5..H.>
Modification Type:MajorLast Reviewed:2/20/2004
Keywords:kbbug kbfix kbnetwork KB163578
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