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TCP/IP issues with AIX 5.2 (running Cloverleaf v5.5)

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  • June 20, 2008 at 5:34 pm #50119
    Alise Blankenship
    Participant

      Hello All,

      We are having trouble with the TCP/IP protocol on our server merging transactions together. Has anyone else had this problem? Is there a patch or something that we need for the O/S?

      When it’s the same message being retransmitted that gets merged, it seems to work out. But when it’s two different message transactions getting merged, it results in data loss. The result never makes it to the receiving system, and Cloverleaf never receives the transaction acknowledgment for it. We do have the current version of the HealthVision recovery code and it is running in the threads. It does appear that this is occurring only on the high volume threads.

      Any help or advice you could give us would be greatly appreciated!

      TIA

      Alise Blankenship

      Interface Analyst

      Tricore Reference Laboratories

      alise.blankenship@tricore.org

      (505) 938-8674

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      • June 23, 2008 at 3:00 pm #64940
        Russ Ross
        Participant

          Are you saying that what is in your SMAT file is not representative of what the foreign TCP/IP listner is receiving?

          In other words which of these 2 cases best describes your problem:

          CASE 1

          – merge message in cloverleaf

          – message goes to SMAT but some of the merges are missing

          – SMAT messages sent out via TCP/IP

          CASE 2

          – sequential message flow in cloverleaf

          – message goes to SMAT

          – SMAT message goes out via TCP/IP and merges with previous sent message

          I ask because I was not aware that TCP/IP would merge messages.

          Yes it does send packets and reassemble them if that is what you mean by merging messages.

          Long ago when machines were less powerfull, cloverleaf could over run the TCP/IP input buffer on the foriegn system when it had too much to send too fast.

          However, the ACKs are intended to keep this problem from happening even on those old slow systems.

          Russ Ross
          RussRoss318@gmail.com

        • June 23, 2008 at 3:25 pm #64941
          Alise Blankenship
          Participant

            Hi Russ,

            Case 2 is what we are seeing.

            Alise

          • June 23, 2008 at 3:54 pm #64942
            Russ Ross
            Participant

              Yikes!

              Russ Ross
              RussRoss318@gmail.com

            • June 23, 2008 at 4:20 pm #64943
              Alise Blankenship
              Participant

                By the way, this is happening in Cloverleaf, not on the receiving system. We have TCP iptrace logs running on the Cloverleaf engine and they are showing us the problem is on the Cloverleaf side. It does happen mainly during peak performance periods, so we do believe is has to do with volume. But we can’t tell why it is happening.

                What appears to be happening is that a message that has multiple packets will have a separate packet ID for each packet with a single message ID assigned to all packets associated with a message and used for acking the message. When a new message is merged with a packet from the previous message, it receives the same message ID as the previous message. So when the receiving system finally receives all the packets (from both messages), it acks the message based on the message ID assigned and Cloverleaf never recieves an ACK for the second message because it has the same message ID as the first message. I know this sounds confusing but I don’t know how else to explain what we are seeing.

                Please let me know if you have any suggestions. I have a call into support but they are just as stumped as I am.

                Thanks.

                Alise

              • June 23, 2008 at 7:20 pm #64944
                Russ Ross
                Participant

                  I’m curious to hear what OS you are running on.

                  I’ve observed TCP/IP to be more problematic on MS Windows servers.

                  Another question pops into my mind, “Are you running on any kind of virtual shared environment like VMware, or is it a dedicated cloverleaf server?”

                  Russ Ross
                  RussRoss318@gmail.com

                • June 24, 2008 at 4:25 pm #64945
                  Alise Blankenship
                  Participant

                    Hi Russ,

                    We are running Cloverleaf v5.5 on AIX 5L v5.3. We have a dedicated IBM server set up to the recommended specs received from Quovadx in 2007.

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