Protocol Error: NAK out of window - Protocols

This is a discussion on Protocol Error: NAK out of window - Protocols ; Hi, I am pretty new to kermit but pretty computer savey. I built a script to connect to ministry of health to send health #'s for validity check. The file transfer fails around 25-30% of the time on error "Protocol ...

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Thread: Protocol Error: NAK out of window

  1. Protocol Error: NAK out of window

    Hi,

    I am pretty new to kermit but pretty computer savey. I built a script to
    connect to ministry of health to send health #'s for validity check. The
    file transfer fails around 25-30% of the time on error "Protocol Error: NAK
    out of window". Any ideas would be greatful. Do you think adding "robust"
    would do anything positive? I only get a few chances to submit a transfer
    per day so I try to keep the guesses to a minimum.

    My set up is as follows with a few comments added that are not in the
    running script:

    --------------
    SET DIAL DISPLAY ON
    set retry-limit 0 --this makes no difference ..
    set modem type generic -- tried 3 different modems and they all get the NAK
    error occasionally..usr, boca and creativelabs
    set line /dev/tty1
    set speed 38400
    set stop-bits 1
    SET FLOW RTS/CTS
    set protocol kermit
    dial 19999999999 (fake #)
    INPUT 8 {Please log on}
    IF FAIL quit 1 MSG999 did not present a login prompt. Run Terminated.
    PAUSE 1
    OUTPUT useridxx\{13}
    INPUT 8 {Password?}
    IF FAIL quit 1 MSG999 did not present a Password prompt. Run Terminated.
    PAUSE 1
    OUTPUT pwxxxxx\{13}

    send filename.txt
    SET EXIT WARNING OFF
    EXIT
    --------------

    here is the transaction log from kermit:

    Transaction Log: C-Kermit 8.0.209, 17 Mar 2003
    IBM AIX 4.3
    Tue Oct 28 06:44:07 2003

    Transaction begins Tue Oct 28 06:44:52 2003

    Global file mode: binary

    Sending filename.txt
    as filename.TXT
    mode: text
    xfer character set ASCII
    file character set US ASCII
    complete, size: 60517

    Transaction complete Tue Oct 28 06:45:33 2003

    elapsed time (seconds) : 31
    effective data rate : 1895

    Protocol Error: NAK out of window

    Transaction complete Tue Oct 28 06:45:33 2003

    elapsed time (seconds) : 32
    effective data rate : 1856

    failed: NAK out of window
    Transaction Log Closed

    ----

    Here is the same log of one that worked with no changes to the script:

    Transaction Log: C-Kermit 8.0.209, 17 Mar 2003
    IBM AIX 4.3
    Tue Oct 28 16:11:46 2003

    Transaction begins Tue Oct 28 16:12:49 2003

    Global file mode: binary

    Sending filename.txt
    as filename.TXT
    mode: text
    xfer character set ASCII
    file character set US ASCII
    complete, size: 62854

    Transaction complete Tue Oct 28 16:13:18 2003

    elapsed time (seconds) : 20
    effective data rate : 2996

    Transaction Log Closed

    ---








  2. Re: Protocol Error: NAK out of window

    On Thu, 30 Oct 2003, computer person wrote:

    > Hi,
    >
    > I am pretty new to kermit but pretty computer savey. I built a script to
    > connect to ministry of health to send health #'s for validity check. The
    > file transfer fails around 25-30% of the time on error "Protocol Error: NAK
    > out of window". Any ideas would be greatful. Do you think adding "robust"
    > would do anything positive? I only get a few chances to submit a transfer
    > per day so I try to keep the guesses to a minimum.


    I was hoping Frank would respond to this one as his reply would be much
    better than mine, I'm sure, but there's been no reply from Frank so maybe
    tthis post didn't reach his news server even though it got to me and to
    Google Groups.

    Yes, I think "robust" would help. So might "set window-size 1". The
    error message seems clear. I think the sender is receiving a NAK to
    a packet that has already been released from the window, presumably because
    it was already ACKed. This would indicate at least one side of the
    transfer does not implement the protocol correctly. Your logs indicate
    the sender (your side) is C-Kermit 8.0.209. I would guess the problem
    is with the receiver. What Kermit is running there?

    > My set up is as follows with a few comments added that are not in the
    > running script:
    >
    > --------------
    > SET DIAL DISPLAY ON
    > set retry-limit 0 --this makes no difference ..
    > set modem type generic -- tried 3 different modems and they all get the NAK
    > error occasionally..usr, boca and creativelabs
    > set line /dev/tty1
    > set speed 38400
    > set stop-bits 1
    > SET FLOW RTS/CTS
    > set protocol kermit
    > dial 19999999999 (fake #)
    > INPUT 8 {Please log on}
    > IF FAIL quit 1 MSG999 did not present a login prompt. Run Terminated.
    > PAUSE 1
    > OUTPUT useridxx\{13}
    > INPUT 8 {Password?}
    > IF FAIL quit 1 MSG999 did not present a Password prompt. Run Terminated.
    > PAUSE 1
    > OUTPUT pwxxxxx\{13}
    >


    Presumably the snipped part has to do with starting a Kermit receiver
    at the remote end. Again, what Kermit is this? How does it identify
    itself?

    > send filename.txt
    > SET EXIT WARNING OFF


    Instead of the above, why not "close connection" and/or "hangup"?

    > EXIT
    > --------------
    >
    > here is the transaction log from kermit:
    >
    > Transaction Log: C-Kermit 8.0.209, 17 Mar 2003
    > IBM AIX 4.3
    > Tue Oct 28 06:44:07 2003
    >
    > Transaction begins Tue Oct 28 06:44:52 2003
    >
    > Global file mode: binary
    >
    > Sending filename.txt
    > as filename.TXT
    > mode: text
    > xfer character set ASCII
    > file character set US ASCII
    > complete, size: 60517
    >
    > Transaction complete Tue Oct 28 06:45:33 2003
    >
    > elapsed time (seconds) : 31
    > effective data rate : 1895
    >
    > Protocol Error: NAK out of window
    >
    > Transaction complete Tue Oct 28 06:45:33 2003
    >
    > elapsed time (seconds) : 32
    > effective data rate : 1856
    >
    > failed: NAK out of window
    > Transaction Log Closed


    This seems to indicate the error doesn't occur until after the send
    completed. I don't know why this would be, but it seems clear that
    at least one side is doing something wrong. Is the file received
    completely in this case?

    >
    > ----
    >
    > Here is the same log of one that worked with no changes to the script:
    >
    > Transaction Log: C-Kermit 8.0.209, 17 Mar 2003
    > IBM AIX 4.3
    > Tue Oct 28 16:11:46 2003
    >
    > Transaction begins Tue Oct 28 16:12:49 2003
    >
    > Global file mode: binary
    >
    > Sending filename.txt
    > as filename.TXT
    > mode: text
    > xfer character set ASCII
    > file character set US ASCII
    > complete, size: 62854
    >
    > Transaction complete Tue Oct 28 16:13:18 2003
    >
    > elapsed time (seconds) : 20
    > effective data rate : 2996
    >
    > Transaction Log Closed
    >
    > ---
    >



    --
    Mark Sapiro The highway is for gamblers,
    San Francisco Bay Area, California better use your sense - B. Dylan


  3. Re: Protocol Error: NAK out of window

    On Fri, 31 Oct 2003, Mark Sapiro wrote:

    > On Thu, 30 Oct 2003, computer person wrote:




    > > My set up is as follows with a few comments added that are not in the
    > > running script:
    > >
    > > --------------
    > > SET DIAL DISPLAY ON
    > > set retry-limit 0 --this makes no difference ..
    > > set modem type generic -- tried 3 different modems and they all get the NAK
    > > error occasionally..usr, boca and creativelabs
    > > set line /dev/tty1
    > > set speed 38400
    > > set stop-bits 1
    > > SET FLOW RTS/CTS


    One more thing...

    Are you sure your modem is set to use RTS/CTS flow control and RTS and CTS
    are properly connected and not "faked out" in the cable? If not, it is not
    likely to cause your particular symptom, but it could be the cause of the
    communication error that precipitates the symptom.

    --
    Mark Sapiro The highway is for gamblers,
    San Francisco Bay Area, California better use your sense - B. Dylan


  4. Re: Protocol Error: NAK out of window

    In article ,
    Mark Sapiro wrote:
    : On Thu, 30 Oct 2003, computer person wrote:
    :> I am pretty new to kermit but pretty computer savey. I built a script to
    :> connect to ministry of health to send health #'s for validity check. The
    :> file transfer fails around 25-30% of the time on error "Protocol Error:
    :> NAK out of window". Any ideas would be greatful. Do you think adding
    :> "robust" would do anything positive? I only get a few chances to submit a
    :> transfer per day so I try to keep the guesses to a minimum.
    :
    : I was hoping Frank would respond to this one as his reply would be much
    : better than mine, I'm sure...
    :
    Not necessarily, but something must be wrong with our news service because
    the original post never came in here. Or at least I missed it somehow --
    hard to say, too many things changing at once at our place.

    : Yes, I think "robust" would help. So might "set window-size 1". The
    : error message seems clear. I think the sender is receiving a NAK to
    : a packet that has already been released from the window, presumably because
    : it was already ACKed. This would indicate at least one side of the
    : transfer does not implement the protocol correctly. Your logs indicate
    : the sender (your side) is C-Kermit 8.0.209. I would guess the problem
    : is with the receiver. What Kermit is running there?
    :
    That's the key question of course. We have not had very good experience
    with third-party Kermit implementations, as you can see from:

    http://www.columbia.edu/kermit/ckermit70.html#x4.22
    http://www.columbia.edu/kermit/ckermit80.html#x15
    http://www.columbia.edu/kermit/kermit.html#notslow

    : This seems to indicate the error doesn't occur until after the send
    : completed. I don't know why this would be, but it seems clear that
    : at least one side is doing something wrong. Is the file received
    : completely in this case?
    :
    If you can collect a packet log (tell C-Kermit to "log packets") I can
    take a look and see how the error comes about.

    In any case, read at least the first two links above and try some of the
    suggestions. You can also consult Chapter 10, "Solving File Transfer
    Problems" of "Using C-Kermit".

    As Mark suggests, the most likely culprit is a faulty sliding-windows
    implementation in the other Kermit, in which case "set window 1" should
    eliminate the error. Of course it might also slow down the transfers, but
    a slower transfer is still faster than one that failed.

    "Robust" is the last resort, because this results in the slowest throughput.
    If you can get by with long packets but one window slot, the performance
    shouldn't be too bad, unless you're going through a satellite or something.

    - Frank

  5. Re: Protocol Error: NAK out of window

    "Mark Sapiro" wrote in message
    news:Pine.HPX.4.44.0310312142410.27146-100000@fog.ccsf.cc.ca.us...
    > On Fri, 31 Oct 2003, Mark Sapiro wrote:
    >
    > > On Thu, 30 Oct 2003, computer person wrote:

    >
    >
    >
    > > > My set up is as follows with a few comments added that are not in the
    > > > running script:
    > > >
    > > > --------------
    > > > SET DIAL DISPLAY ON
    > > > set retry-limit 0 --this makes no difference ..
    > > > set modem type generic -- tried 3 different modems and they all get

    the NAK
    > > > error occasionally..usr, boca and creativelabs
    > > > set line /dev/tty1
    > > > set speed 38400
    > > > set stop-bits 1
    > > > SET FLOW RTS/CTS

    >
    > One more thing...
    >
    > Are you sure your modem is set to use RTS/CTS flow control and RTS and CTS
    > are properly connected and not "faked out" in the cable? If not, it is

    not
    > likely to cause your particular symptom, but it could be the cause of the
    > communication error that precipitates the symptom.
    >
    > --
    > Mark Sapiro The highway is for gamblers,
    > San Francisco Bay Area, California better use your sense - B. Dylan
    >

    Well, 5 days now and no problem after adding the "robust" command..It's slow
    but it works 100% of the time now!



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