Hi to all.
I'm trying to setup an NTP server. I have an external device that is connected
to a GPS signal and sends to my device the time. My device runs an application
that receives this time and has to fill-in the shared memory of NTP, thus
allowing NTP to adjust system time and to
cloudd...@gmail.com cloudd...@gmail.com wrote:
I've written a simple application for now that writes in the shared memory
segment the information about time following the approach shown here:
http://www.opensource.apple.com/source/ntp/ntp-86/util/sht.c
Can someone please help me?
Thanks in
Just to understand:
when I run ntpq -p, I think that a star (*) symbol should appear in the shared
memory segment that NTPD has choose for keeping the time.
Does the fact that in my output of ntpq I can't see any star means that no one
is filling the memory with good values or that NTPD has
Claudio Persico cloudd...@gmail.com wrote:
Just to understand:
when I run ntpq -p, I think that a star (*) symbol should appear in the
shared memory segment that NTPD has choose for keeping the time.
Before that, you first have to see values appear within the other fields
on the line.
Does
Claudio Persico wrote:
Just to understand:
when I run ntpq -p, I think that a star (*) symbol should appear in the shared
memory segment that NTPD has choose for keeping the time.
This is *only* if ntpd accepts this time source as system peer.
Does the fact that in my output of ntpq I
William Unruh wrote:
Not if you have gps reference at both ends, though why you would not use
the gps as the timesource then I do not know.
The case mentioned by the original poster is just one possible reason.
If you have a GPS controlled NTP server at home, and a fast internet
connection,
Rob wrote:
Ok you are right. In fact I filed bug #2598 myself for a similar
situation... In my case I wanted to compensate for the delay asymmetry
for external users using my GPS reference via my ADSL line. So I
would like to apply such a fudge command to a network interface, not
to a peer
Martin Burnicki martin.burni...@meinberg.de wrote:
This is also what Rob has mentioned in another post of this thread, and
I agree with Rob that a one approach could be to specify (and configure
for ntpd) the systematic error due to asymmetry of your internet connection.
However, this can
On 2014-09-11, Martin Burnicki martin.burni...@meinberg.de wrote:
William Unruh wrote:
Not if you have gps reference at both ends, though why you would not use
the gps as the timesource then I do not know.
The case mentioned by the original poster is just one possible reason.
If you have a
On Tue, Sep 9, 2014 at 6:58 PM, Harlan Stenn st...@ntp.org wrote:
The issue is that the huff-n-puff filter will work in the case where a
symmetrical delay becomes asymmetric, and it will tolerate or
accommodate an asymmetric delay (caused by a large download, for
example) for some period of
Paul tik-...@bodosom.net wrote:
Not to suggest that someone is doing something unreasonable but again
why does time derived from the back-up clock need to be as accurate as
the local clock (say .5ms versus 2ms)? If there's a legitimate need
then trying to solve the problem with the wrong tool
Paul tik-...@bodosom.net wrote:
As an aside has anyone tried shaping traffic to make the
upstream/downstream latencies similar? It would seem more efficient
to apply network solutions to network problems if possible.
That does not work. The asymmetry is not caused by traffic but by
modem
On Thu, Sep 11, 2014 at 12:48 PM, Rob nom...@example.com wrote:
That does not work. The asymmetry is not caused by traffic but by
modem parameters.
The asymmetry is caused by asymmetric latency which is caused (for our
purposes) by asymmetric line speeds. Traffic shaping can change
various
Le 11 sept. 2014 à 18:48, Rob a écrit :
Paul tik-...@bodosom.net wrote:
As an aside has anyone tried shaping traffic to make the
upstream/downstream latencies similar? It would seem more efficient
to apply network solutions to network problems if possible.
That does not work. The
It has been pointed out to me that this page:
http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver28.html
says: The gpsd man page suggests setting minpoll and maxpoll to 4. That
was an attempt to reduce jitter. The SHM driver was fixed
(ntp-4.2.5p138) to collect data each second rather
On 2014-09-11, Rob nom...@example.com wrote:
Martin Burnicki martin.burni...@meinberg.de wrote:
This is also what Rob has mentioned in another post of this thread, and
I agree with Rob that a one approach could be to specify (and configure
for ntpd) the systematic error due to asymmetry of
On 2014-09-11, mike cook michael.c...@sfr.fr wrote:
Le 11 sept. 2014 ? 18:48, Rob a ?crit :
Paul tik-...@bodosom.net wrote:
As an aside has anyone tried shaping traffic to make the
upstream/downstream latencies similar? It would seem more efficient
to apply network solutions to network
On Thu, Sep 11, 2014 at 2:29 PM, William Unruh un...@invalid.ca wrote:
I doubt that NAT would add much assymetry
NAT is symmetric. Otherwise it wouldn't work. But I don't see how
that's part of anything at hand.
And yes the A in ADSL stands for Asymmetric. If you see the word
home in
On Thu, Sep 11, 2014 at 2:08 PM, mike cook michael.c...@sfr.fr wrote:
Did I miss something?
On Tue, Sep 9, 2014 at 3:17 PM, Rich Wales ri...@richw.org wrote:
My home LAN is connected to my school's network via a cable modem.
If we make the (safe) assumption of a common cable ISP/FiOS in the
Le 11 sept. 2014 à 21:08, Paul a écrit :
On Thu, Sep 11, 2014 at 2:08 PM, mike cook michael.c...@sfr.fr wrote:
Did I miss something?
On Tue, Sep 9, 2014 at 3:17 PM, Rich Wales ri...@richw.org wrote:
My home LAN is connected to my school's network via a cable modem.
If we make the
The offset may be a function of distance.
Try this experiment:
Set up your ntp.conf file to have three servers (all examples assume you
are located in Eastern USA):
1. A relatively unused stratum 1 or 2 server as close to you as possible.
2. A relatively unused stratum 1 or 2 server about 1,000
Paul tik-...@bodosom.net wrote:
On Thu, Sep 11, 2014 at 2:29 PM, William Unruh un...@invalid.ca wrote:
I doubt that NAT would add much assymetry
NAT is symmetric. Otherwise it wouldn't work. But I don't see how
that's part of anything at hand.
I never claimed it is part of the asymmetry, I
mike cook michael.c...@sfr.fr wrote:
Le 11 sept. 2014 à 18:48, Rob a écrit :
Paul tik-...@bodosom.net wrote:
As an aside has anyone tried shaping traffic to make the
upstream/downstream latencies similar? It would seem more efficient
to apply network solutions to network problems if
mike cook michael.c...@sfr.fr wrote:
Le 11 sept. 2014 à 21:08, Paul a écrit :
On Thu, Sep 11, 2014 at 2:08 PM, mike cook michael.c...@sfr.fr wrote:
Did I miss something?
On Tue, Sep 9, 2014 at 3:17 PM, Rich Wales ri...@richw.org wrote:
My home LAN is connected to my school's network via
cloudd...@gmail.com writes:
My configuration file il se following:
#
driftfile /var/log/ntp.drift# path for drift file
logfile /var/log/ntp.log# alternate log file
# shared memory configuration
server 127.127.28.0 minpoll 4 maxpoll 4 prefer
fudge 127.127.28.0 time1 0.420
There are a bunch of issues here, and I don't think there is a simple
answer.
For starters, there is static asymmetry and dynamic asymmetry.
One of the core issues is that NTP is frequently multihop, and the
routing for at least some of these connections can spontaneously change.
Declaring an
On 11/09/14 22:11, Rob wrote:
mike cook michael.c...@sfr.fr wrote:
Le 11 sept. 2014 à 21:08, Paul a écrit :
On Thu, Sep 11, 2014 at 2:08 PM, mike cook michael.c...@sfr.fr wrote:
Did I miss something?
On Tue, Sep 9, 2014 at 3:17 PM, Rich Wales ri...@richw.org wrote:
My home LAN is
David Woolley david@ex.djwhome.demon.invalid wrote:
On 11/09/14 22:11, Rob wrote:
mike cook michael.c...@sfr.fr wrote:
Le 11 sept. 2014 à 21:08, Paul a écrit :
On Thu, Sep 11, 2014 at 2:08 PM, mike cook michael.c...@sfr.fr wrote:
Did I miss something?
On Tue, Sep 9, 2014 at 3:17 PM,
mike cook wrote:
Le 11 sept. 2014 à 21:08, Paul a écrit :
On Thu, Sep 11, 2014 at 2:08 PM, mike cook michael.c...@sfr.fr wrote:
Did I miss something?
On Tue, Sep 9, 2014 at 3:17 PM, Rich Wales ri...@richw.org wrote:
My home LAN is connected to my school's network via a cable modem.
If we
29 matches
Mail list logo
