[time-nuts] Serial port server .. any interest in a write up on using ?

Hal Murray hmurray at megapathdsl.net
Wed May 23 08:54:20 UTC 2012


attila at kinali.ch said:
> On an ethernet it looks quite different:

[snip lots of low jitter samples]

> Network is a destkop - switch1 - switch2 - ntp box.

> The switches are two Level1 Gbit smart switches. The desktop is a ~4y old
> Xeon 2GHz system with a Gbit interface The ntp box is a AMD Geode LX 500MHz
> system with a 100MBit interface Both running linux.

> There aren't noticable more jitter for moderate (1-2 MByte/s) traffic.
> (Probably visible if i would do a statistical analysis...but..) 

1-2 megabytes/sec is 8-16 megabits/sec.  You won't get into serious troubles 
until you saturate a link.  With modern CPUs, it's trivial to saturate 100 
megabit links and not very hard to saturate 1 gigabit links.

With older/slower CPUs, you might run into problems a lot sooner.

I'm not trying to discourage using these boxes.  Just don't be surprised when 
you run into quirks if you are trying to use them for timing.  (and don't 
depend upon loud mouths like me to point out all possible ways they can screw 
up)



-- 
These are my opinions.  I hate spam.






More information about the time-nuts mailing list