Network cable disconnect

Eric Norum norume at
Wed Jun 20 16:40:41 UTC 2007

The original intent of the Internet was to be able to get data  
through even in the event of a nuclear attack.  Allowing a minute for  
a damaged connection to be cleared or routed around is quite  
reasonable under those circumstances.   What is your need to detect a  
disconnected cable that quickly?

On Jun 20, 2007, at 11:26 AM, Joel Sherrill wrote:

> Camilo Alejandro Arboleda wrote:
>> Hello,
>> We working with a PC386 based board, with NE2000 compatible network
>> adapter. I've seen that disconnecting the network cable doesn't cause
>> the "write()" function to fail immediately, but it takes about a
>> minute to detect the network disconnection. Is it possible to detect
>> cable faults faster? Am I doing something wrong?
> Did you turn on debug in the driver and try it?
> Is there any output at all from the driver now?
> I don't see anything explicitly in the driver about cable disconnect.
> I do see ne_watchdog which is hooked to if_watchdog.  The
> associated if_timer value is 2 which I think is 2 seconds based
> upon IFNET_SLOWHZ and hz being rtems_bsdnet_ticks_per_second.
> But this looks like a Tx timeout and is way shorter than what you
> are seeing.

Eric Norum <norume at>
Advanced Photon Source
Argonne National Laboratory
(630) 252-4793

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