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Flow control in FreeBSD

Discussion in 'Networking' started by m69, Jul 19, 2012.

  1. m69

    m69 New Member

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    I want to use flow control in FreeBSD for an interface. What I should to do for enabel or disable it in FreeBSD.
    Thanks
     
  2. michaelrmgreen

    michaelrmgreen Member

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    Serial flow control, either software (XON/XOFF) or hardware (CTS/RTS or DSR/DTR) is controlled through getty(8). Have a look at the man page for getty and peruse the related files /etc/ttys and /etc/gettytab. There's also a useful Handbook page here: http://www.freebsd.org/doc/handbook/serial.html

    I struggled for years trying to get good flow control to high speed terminals and it never worked to my satisfaction. In the end I accepted a lower data rate (9600 Baud) and no flow control.

    [Edit] Further information: If you don't use flow control you can use simpler serial cables but you need to change std.9600 to 3wire.9600 in /etc/ttys.
     
    m69 thanks for this.
  3. m69

    m69 New Member

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    Thanks but it wasn't my aim. I want use flow control for a network interface in FreeBSD because I must do a test and I can't because flow control is enable. Is it enable as default?
    How I can disable it?
     
  4. quintessence

    quintessence Member

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    Hello,

    As I see in changes by default it should be disabled in FreeBSD-9, and if you enable it you should see it in the ifconfig(8) output for example as:

    Code:
    100baseTX-FDX-flow
    , where -flow indicates that flow control is enabled on your NIC.

    From /usr/src/sys/net/if_media.h:

     
  5. phoenix

    phoenix Moderator Staff Member Moderator

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    ifconfig(8), especially the parts about -m (to see what mediaopts the driver supports) and mediaopts._