[Soekris] Net4501 as NTP server?

[Alex S.]

Hi,I have a net4501, and I would like to use it as a GPS-based NTP server for my network. So, I have a few questions: 1) What would be the best OS for this purpose? One of the BSDs or Linux?2) I read somewhere that the second serial port isn't actually functional on this board. Is this true? I will be using an OEM GPS module so the internal serial port would be useful.3) I also read somewhere that the serial ports on these boards have too much latency for a PPS signal, so could I use one of the GPIO pins for the PPS input instead?4) Would it be hard to replace the onboard crystal with a TXCO or similar? Thanks in advance,Alex

[nikns]

I would definetly prefer OpenBSD:
http://undeadly.org/cgi?action=article&sid=20060528183921

Post by Alex S.
Hi,I have a net4501, and I would like to use it as a GPS-based NTP server for my network. So, I have a few questions: 1) What would be the best OS for this purpose? One of the BSDs or Linux?2) I read somewhere that the second serial port isn't actually functional on this board. Is this true? I will be using an OEM GPS module so the internal serial port would be useful.3) I also read somewhere that the serial ports on these boards have too much latency for a PPS signal, so could I use one of the GPIO pins for the PPS input instead?4) Would it be hard to replace the onboard crystal with a TXCO or similar? Thanks in advance,Alex
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[Stuart Henderson]

Post by Alex S.
Hi,I have a net4501, and I would like to use it as a GPS-based
NTP server for my network. So, I have a few questions: 1) What would
be the best OS for this purpose? One of the BSDs or Linux?

At this point in time, and since you're talking about replacing
xtals, probably FreeBSD. See http://phk.freebsd.dk/soekris/pps/

[Poul-Henning Kamp]

In message <BAY106-***@phx.gbl>, "Alex S." writes:

The net4501 is about the best platform you can get for an NTP server,
seen in a cost/performance light.

See:
http://phk.freebsd.dk/soekris/pps/

Using a clock source with improved stability will certainly help,
just unsolder the 33.3 MHz Xtal and feed in the external signal.

The Elan datasheet has the info on what correct drive conditions is.

[Emmanuel Dreyfus]

Post by Alex S.
Hi,I have a net4501, and I would like to use it as a GPS-based NTP server
for my network. So, I have a few questions: 1) What would be the best OS
for this purpose? One of the BSDs or Linux?

Anyone of these OS will do it. OpenBSD and FreeBSD have been advised, so
I'll advise my faroutie BSD: NetBSD would do the job nicely.

--
Emmanuel Dreyfus
***@netbsd.org

[Alex S.]

Yes, everyone has already pointed me to your page ;) But how did you connect the PPS signal? Serial or GPIO? Do you have more info on the software side of things? And do you know off hand of a good (but low-cost) oscillator I could use? Thanks,Alex

[Poul-Henning Kamp]

Post by Emmanuel Dreyfus

Post by Alex S.
Hi,I have a net4501, and I would like to use it as a GPS-based NTP server
for my network. So, I have a few questions: 1) What would be the best OS
for this purpose? One of the BSDs or Linux?

Anyone of these OS will do it. OpenBSD and FreeBSD have been advised, so
I'll advise my faroutie BSD: NetBSD would do the job nicely.

Actually, now that NetBSD has imported timecounters from FreeBSD I will
second that. OpenBSD has very primitive timekeeping code in the kernel.

[Ask Bjørn Hansen]

On Jun 16, 2006, at 11:30 AM, Alex S. wrote:

Somewhat related: I have a 4501 running FreeBSD 6 working as a
stratum 2 server (ntp1.us.grundclock.com) that does about 600
requests per second. If all the clients were well-behaved that
translates into something like 250-600k clients. It runs at about
85% capacity as far as I can tell.

I actually bought a few PC Engines WRAP boxes to experiment to do the
same thing (figuring they'd have a bit more capacity for the same
price and for a simple stratum 2 box I don't need the extra features
the Soekris have), but the BIOS isn't nearly as nice as the Soekris
one so I've never gotten them running properly (they hang on the
FreeBSD boot manager and don't get me started on the PXE Boot
stuff). The Soekris boxes on the other hand are great -- maybe
except for the color of the standard case. :-)


- ask

[Poul-Henning Kamp]

Post by Poul-Henning Kamp

Post by Emmanuel Dreyfus
Anyone of these OS will do it. OpenBSD and FreeBSD have been advised, so
I'll advise my faroutie BSD: NetBSD would do the job nicely.

Actually, now that NetBSD has imported timecounters from FreeBSD I will
second that. OpenBSD has very primitive timekeeping code in the kernel.

Actually this has been changing in the last weeks. For one
Otto Moerbeck is pulling in changes from DragonflyBSD and also
support for DCF77/HBG as well as GPS/NMEA time signals has been
added recently.

If he pulls timecounters from DFBSD, then fine, otherwise my position
remain unchanged.

Please notice that validating that the kernel part of a UNIX does
even decent timekeeping takes quite a bit of measuring with a good
timeinterval counter. You cannot validate that performance with
software alone.