DOCUMENT:Q313151 08-AUG-2002 [sna] TITLE :COMTI TCP/IP MS Link Fails If Less Data Is Returned Than Sent PRODUCT :Microsoft SNA Server PROD/VER::4.0 SP2,4.0 SP3,4.0 SP4 OPER/SYS: KEYWORDS:sna4 kbsna400sp1 kbsna400sp2 kbsna400sp3 kbhis2000 kbhis2000bug kbsna400sp4 ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Host Integration Server 2000 - Microsoft SNA Server, versions 4.0 SP2, 4.0 SP3, 4.0 SP4 ------------------------------------------------------------------------------- SYMPTOMS ======== When you use COM Transaction Integrator (COMTI) and TCP/IP by means of MS Link, with a modified version of the Microsoft supplied child server sample program (Mscmtics.cbl), and if the data that is returned from the mainframe host program is fewer bytes than what was sent to the mainframe host program, you receive an error message that is similar to the following: COMTI Event 102: Runtime error 2159 : the tcp transport received a socket error while attempting to receive user data expected length 34, received length 25. IP ADDRESS : (address) port number (port). Trans ID : (trans ID) CAUSE ===== This problem occurs when the child server program on the mainframe is designed to return fewer bytes of data than are received from COMTI. The Microsoft-supplied Mscmtics.cbl child server sample program is designed to return at least as many bytes of data as are sent to the host, even if the COMTI type library is designed to expect fewer bytes of data to be returned. If the type library is designed to receive fewer bytes, the COMTI runtime ignores the additional bytes that are returned by the Mscmtics.cbl child server program. For example, the error scenario occurs as follows: - The host expects to receive 34 bytes of data to process, for example, a first name, a last name, and an address. - The host takes that 34 bytes of information and goes to a database to get additional information to return. - The host returns only 25 bytes (for example, the phone number). - The modified version of the child server program sends only 25 bytes of data back to the COMTI runtime. In this case, if COMTI receives only 25 bytes from the host, this error occurs because the COMTI runtime was designed to expect to receive at least as many bytes of data as it sent (34 bytes). RESOLUTION ========== For SNA Server 4.0, the product will not be changed to allow for returning less data than is sent to the host when using TCP/IP by means of MS Link. STATUS ====== Microsoft has confirmed that this is a problem in Microsoft Host Integration Server 2000. Microsoft has confirmed that this is a problem in Microsoft SNA Server Version 4.0. MORE INFORMATION ================ A COMTI tracebits trace of a method call that sends 34 bytes to the mainframe and receives 25 bytes in return shows the TCP Transport Link exiting abnormally as follows: Feb 15 17:19:07.296 18060 TCP Transport DistribLink is sending user data, length = 34 Feb 15 17:19:07.296 18010 TCP Transport SendBuf entered, 34 bytes to send Feb 15 17:19:07.296 18130 TCP Transport SendBuf: Bytes sent=34. Feb 15 17:19:07.296 18011 TCP Transport SendBuf exited normally Feb 15 17:19:07.531 18016 TCP Transport ReceiveBuf entered, maximum 34 bytes to receive Feb 15 17:19:07.531 18090 TCP Transport RecvBuf: Remaining=34, receive size=34. Feb 15 17:19:07.531 18092 TCP Transport RecvBuf: Bytes received=25, total received so far=25. Feb 15 17:19:07.531 18090 TCP Transport RecvBuf: Remaining=9, receive size=9. Feb 15 17:19:07.531 18091 TCP Transport RecvBuf: Shutdown occurred. Feb 15 17:19:07.531 18017 TCP Transport ReceiveBuf exited normally, 25 bytes rcvd, Data Complete = 1 Feb 15 17:19:07.531 18024 TCP Transport Link exited abnormally, HRESULT = 0000000b Additional query words: ====================================================================== Keywords : sna4 kbsna400sp1 kbsna400sp2 kbsna400sp3 kbhis2000 kbhis2000bug kbsna400sp4 Technology : kbAudDeveloper kbSNAServSearch kbHostIntegServ2000 kbSNAServ400SP2 kbSNAServ400SP3 kbSNAServ400SP4 Version : :4.0 SP2,4.0 SP3,4.0 SP4 Issue type : kbbug Solution Type : kbpending ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 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