Network Delay in TCP/IP. - VxWorks

This is a discussion on Network Delay in TCP/IP. - VxWorks ; Hello, We have a terminal running VxWorks 5.4.2 connected to the network thru an ADSL line. We have been experiencing some problems on the connection because sometimes it is imposible to ping the terminal as it always times out unless ...

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Thread: Network Delay in TCP/IP.

  1. Network Delay in TCP/IP.

    Hello,

    We have a terminal running VxWorks 5.4.2 connected to the network thru
    an ADSL line. We have been experiencing some problems on the

    connection because sometimes it is imposible to ping the terminal as
    it always times out unless you send it a second ping message. We

    have checked that the ping message has reached the terminal but
    somehow it seems to be accumulated somewhere until the terminal

    receives subsequent messages.

    This type of behavior happens also when using a TCP connection.
    Sometimes the messages take quite a long time to reach the
    application

    level in the terminal although we have checked that they had actually
    arrived into the ethernet card of the terminal.

    This is quite a random behavior, sometimes it happens, sometimes not,
    on the same ethernet network.

    I have heard that there were some problems in the past with the
    communications stack or the netTask priority, or even with the RTL

    8139 Ethernet Card.


    Could somebody please give us a clue about what is happening?

    Our execution environment is:

    VxWorks 5.4.2
    BSP pcPENTIUM ver 1.2/0
    Ethernet Card Realtek RTL 8139
    Intel Celeron 300Mhz
    128 MB RAM



    Thanks a lot in advance.


  2. Re: Network Delay in TCP/IP.

    Ricardo escribió:
    > Hello,
    >
    > We have a terminal running VxWorks 5.4.2 connected to the network thru
    > an ADSL line. We have been experiencing some problems on the
    >
    > connection because sometimes it is imposible to ping the terminal as
    > it always times out unless you send it a second ping message. We
    >
    > have checked that the ping message has reached the terminal but
    > somehow it seems to be accumulated somewhere until the terminal
    >
    > receives subsequent messages.
    >
    > This type of behavior happens also when using a TCP connection.
    > Sometimes the messages take quite a long time to reach the
    > application
    >
    > level in the terminal although we have checked that they had actually
    > arrived into the ethernet card of the terminal.
    >
    > This is quite a random behavior, sometimes it happens, sometimes not,
    > on the same ethernet network.
    >
    > I have heard that there were some problems in the past with the
    > communications stack or the netTask priority, or even with the RTL
    >
    > 8139 Ethernet Card.
    >
    >
    > Could somebody please give us a clue about what is happening?
    >
    > Our execution environment is:
    >
    > VxWorks 5.4.2
    > BSP pcPENTIUM ver 1.2/0
    > Ethernet Card Realtek RTL 8139
    > Intel Celeron 300Mhz
    > 128 MB RAM
    >
    >
    >
    > Thanks a lot in advance.
    >


    In my experience (VxWorks 5.4.2, i386/Pentium targets), all the problems
    we have had to date were caused by defective drivers or bad application
    code.

    Do you have the sources for the Ethernet driver? If so, try debugging
    it. I once used a driver for the cs8900, delivered by the manufacturer,
    which had a nasty bug. It would drop a packet from time to time, and
    even stall. Eventually I found it nad fixed it. In any case, try to get
    the latest drivers.

    As you are using something like a PC, you could also try another
    "standard" Ethernet card and its associated driver.

    Good luck.

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