[time-nuts] GPS, NTP, and Cisco routers...

Scott McGrath scmcgrath at gmail.com
Mon Oct 6 16:08:22 UTC 2008


The Oscillator on a 25xx is a Saronix 3.864Mhz oscillator chip.   Also see this


This is from one of Cisco's configuration guides - my documentation
unfortunately was covered by a Cisco NDA I am looking for a public
document which describes serial interrupt handling.    But when you
think about it input must also have a interrupt handler otherwise one
would never be able to send a break sequence and have it acted upon.



!--- Reduce async framing overhead to improve throughput.

 speed 115200

!--- The AUX port on the 2600 supports a speed of 115200.
!--- Note: If you route through the AUX port, each character generates a
!--- processor interrupt. This is an abnormally high load on the CPU,
!--- which can be resolved if you use a lower AUX port speed.

 flowcontrol hardware

!--- This configures RTS/CTS flow control.



On Sun, Oct 5, 2008 at 10:54 PM, Dave hartzell <hartzell at gmail.com> wrote:
> Hmmm...
>
> I would be interested to see those docs.
>
> I find it hard to believe that a pin going high on a serial port would
> generate an interrupt unless a process is listening to it.
>
> Its not that I don't believe you, I just have never run into this in
> my 12+ years dealing with Cisco.  Output logging crashes for sure, but
> never anything with terminal servers.
>
> Scary stuff.  I'm going to unplug all my consoles now!  ;-)
>
>
> On Sun, Oct 5, 2008 at 11:28 AM, Scott McGrath <scmcgrath at gmail.com> wrote:
>> Interrupts happen on any serial operation I'll dig out the relevant
>> doc's as another interesting way to crash a 6509 is to have a terminal
>> server randomly generating text.   Been there, got the scars... and
>> the root cause analysis from TAC...
>>
>>
>



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