David Woolley da...@ex.djwhome.demon.invalid wrote:
Rob wrote:
What nearly all of them do is send a query at the specified (or fixed)
interval, and put the time from the reply packet in the clock, stepping
it to that value.
Maybe it cannot be rightfully called SNTP, but it is what we
Rob wrote:
What nearly all of them do is send a query at the specified (or fixed)
interval, and put the time from the reply packet in the clock, stepping
it to that value.
Maybe it cannot be rightfully called SNTP, but it is what we have.
The SNTP supplied with the reference implementation
Danny Mayer wrote:
On 6/16/2010 5:22 PM, Maarten Wiltink wrote:
Marcelo Pimenta marcelopiment...@gmail.com wrote in message
news:aanlktilq6m8apeoasibr-o8mhwifqkfv9xyf6mudr...@mail.gmail.com...
[...]
The NTP algorithm is much more complicated than the SNTP algorithm.
The short, short version:
On 7/8/2010 2:50 AM, David Woolley wrote:
Danny Mayer wrote:
On 6/16/2010 5:22 PM, Maarten Wiltink wrote:
Marcelo Pimenta marcelopiment...@gmail.com wrote in message
news:aanlktilq6m8apeoasibr-o8mhwifqkfv9xyf6mudr...@mail.gmail.com...
[...]
The NTP algorithm is much more complicated than
Danny Mayer ma...@ntp.org wrote:
There has been no attempt to redefine SNTP. RFC 2030 is 15 years old so
it's hardly recent. Tools like ntpdate are not SNTP clients by the
definitions of any RFC you care to name, it just sets the clock. SNTP is
a simplified protocol to discipline the clock and
David,
The basic definition of SNTP has not changed over the yeas, although
rfc5905 does clarify the intended scope and role of primary servers,
secondary servers and clients. It was the expected, but not required,
model that the Unix adjtime() system call be used if the offset was less
than
Danny Mayer wrote:
RFC 2030, which RFC5905 obsoleted, said the same thing. It doesn't
The substring disci appears nowhere in RFC 2030; together with failing
to find anything of the sort in a quick skim, and a specific skim of the
wording around the word clock!, I conclude that RFC 2030
On 6/16/2010 5:22 PM, Maarten Wiltink wrote:
Marcelo Pimenta marcelopiment...@gmail.com wrote in message
news:aanlktilq6m8apeoasibr-o8mhwifqkfv9xyf6mudr...@mail.gmail.com...
[...]
The NTP algorithm is much more complicated than the SNTP algorithm.
The short, short version: there is no
On 6/17/2010 9:46 AM, Marcelo Pimenta wrote:
Yep but I have an equipment for specific use with RFC2030 implemented
because of a standard that I have follow that say it is mandatory SNTP -
RFC2030. My equipment ask for time every minute and frequence tolerance of
the crystal is less then
Marcelo Pimenta wrote:
Yes!! My question is about ms(MILIsecond) a collegue of this forum said that
NTP give nsec accurancy... Is impossible to have usec imagine nsec!
ns (as in less than us) is absolutely possible for NTP, but it cannot be
done over a network, you need a good deal of
On 2010-06-18, Richard B. Gilbert rgilber...@comcast.net wrote:
David J Taylor wrote:
Richard B. Gilbert rgilber...@comcast.net wrote in message
news:fcgdnxzbxfvy7ifrnz2dnuvz_sadn...@giganews.com...
[]
If you have a GPS timing receiver (different from navigation
receiver), with a PPS
Marcelo Pimenta marcelopiment...@gmail.com wrote in message
news:aanlktilffevh94cief43-ewqbc2dtqev4dbbpfs1d...@mail.gmail.com...
[]
Yes, I agree. But we were talking about NTP using Ethernet, so... that's
impossible
Even with Ethernet, temperature variations at the client will have a
Richard B. Gilbert rgilber...@comcast.net wrote in message
news:fcgdnxzbxfvy7ifrnz2dnuvz_sadn...@giganews.com...
[]
If you have a GPS timing receiver (different from navigation receiver),
with a PPS output, one edge of that pulse should be accurate to within
50 nanoseconds. A serial output
On 2010-06-17, Marcelo Pimenta marcelopiment...@gmail.com wrote:
2010/6/17 unruh un...@wormhole.physics.ubc.ca
On 2010-06-16, Marcelo Pimenta marcelopiment...@gmail.com wrote:
2010/6/15 unruh un...@wormhole.physics.ubc.ca
On 2010-06-14, Marcelo Pimenta marcelopiment...@gmail.com wrote:
On 2010-06-17, Marcelo Pimenta marcelopiment...@gmail.com wrote:
2010/6/16 David Woolley da...@ex.djwhome.demon.invalid
Marcelo Pimenta wrote:
Rob, my understading about the use of SNTP and NTP is: while SNTP provides
time synchronization within *one *network, NTP allows a global time
unruh un...@wormhole.physics.ubc.ca wrote in message
news:slrni1mjri.fnp.un...@wormhole.physics.ubc.ca...
On 2010-06-17, Marcelo Pimenta marcelopiment...@gmail.com wrote:
[...] What's your SO?
Define SO.
Operating System in Italian.
Groetjes,
Maarten Wiltink
On 2010-06-16, Marcelo Pimenta marcelopiment...@gmail.com wrote:
2010/6/15 unruh un...@wormhole.physics.ubc.ca
On 2010-06-14, Marcelo Pimenta marcelopiment...@gmail.com wrote:
Hi everybody!!
My question is about Time Accuracy of NTP/SNTP protocol. I want to know
if
is possible to have
On 2010-06-16, Marcelo Pimenta marcelopiment...@gmail.com wrote:
2010/6/16 Rob nom...@example.com
Marcelo Pimenta marcelopiment...@gmail.com wrote:
The idea to have this is not overload the network asking time every
second
to keep my accurancy in 1ms in 100% of time. And the second reason
2010/6/16 David Woolley da...@ex.djwhome.demon.invalid
Marcelo Pimenta wrote:
Rob, my understading about the use of SNTP and NTP is: while SNTP provides
time synchronization within *one *network, NTP allows a global time
You are confusing it with timed. SNTP also expects to use global
2010/6/16 Maarten Wiltink maar...@kittensandcats.net
Marcelo Pimenta marcelopiment...@gmail.com wrote in message
news:aanlktilaoduniqjgpigohpzvjcv_zmsw_tr7naj6b...@mail.gmail.com...
[...] accuracy of 1ms. On a local network 100usec?? Even if we use
only switches(no routers), how is that
2010/6/17 unruh un...@wormhole.physics.ubc.ca
On 2010-06-16, Marcelo Pimenta marcelopiment...@gmail.com wrote:
2010/6/15 unruh un...@wormhole.physics.ubc.ca
On 2010-06-14, Marcelo Pimenta marcelopiment...@gmail.com wrote:
Hi everybody!!
My question is about Time Accuracy of
2010/6/17 unruh un...@wormhole.physics.ubc.ca
On 2010-06-16, Marcelo Pimenta marcelopiment...@gmail.com wrote:
2010/6/16 Rob nom...@example.com
(...)
In my case, I have* only one* network. My Time Server is not a machine,
is a
meinberg GPS. In my point of view, if my source time
Marcelo Pimenta marcelopiment...@gmail.com wrote:
I thought that SNTP was used in a kind of Intranet with no routers and no
internet, so the low latency there is no need of so much calculations to
adjust the clock.
No, SNTP is used by software manufacturers who are too lazy to implement
full
Marcelo Pimenta marcelopiment...@gmail.com wrote:
Yep but I have an equipment for specific use with RFC2030 implemented
because of a standard that I have follow that say it is mandatory SNTP -
RFC2030. My equipment ask for time every minute and frequence tolerance of
the crystal is less then
NTP can deliver a time accuracy of 1nsec?? I my point of view, NTP
includes
methods to estimate the round-trip path delay between the server and
client
but the performance is limited by SO stack latency, it is an Application
Layer protocol.
Marcelo, here's what /my/ NTP achieves:
Marcelo Pimenta marcelopiment...@gmail.com wrote:
In my case, I have* only one* network. My Time Server is not a machine,
is a
meinberg GPS. In my point of view, if my source time were machines, maybe
A Meingerg GPS IS a machine.
I agree, I said machines equipment like PC computers with
2010/6/17 David J Taylor david-tay...@blueyonder.co.uk.invalid
NTP can deliver a time accuracy of 1nsec?? I my point of view, NTP
includes
methods to estimate the round-trip path delay between the server and
client
but the performance is limited by SO stack latency, it is an Application
David,
CONGRATULATIONS!!! Very good tests and presentations!! Very very good!!!
You
gave me real results and all your reports are consistent and show that
it's
impossible to have usec and nsec precision using NTP though Ethernet.
You
have SO stack latency and it's a Layer 7 protocol!!!
One
Yes!! My question is about ms(MILIsecond) a collegue of this forum said that
NTP give nsec accurancy... Is impossible to have usec imagine nsec!
Thanks
2010/6/17 David J Taylor david-tay...@blueyonder.co.uk.invalid
David,
CONGRATULATIONS!!! Very good tests and presentations!! Very very
Marcelo Pimenta wrote:
Yes!! My question is about ms(MILIsecond) a collegue of this forum said that
NTP give nsec accurancy... Is impossible to have usec imagine nsec!
Thanks
If you have a GPS timing receiver (different from navigation receiver),
with a PPS output, one edge of that pulse
In article aanlktil2jbpj9p5eqfykgnjev8_ejr6ic_0cuodgf...@mail.gmail.com,
Marcelo Pimenta marcelopiment...@gmail.com writes:
I thought that SNTP was used in a kind of Intranet with no routers and no
internet, so the low latency there is no need of so much calculations to
adjust the clock.
I
2010/6/17 Richard B. Gilbert rgilber...@comcast.net
Marcelo Pimenta wrote:
Yes!! My question is about ms(MILIsecond) a collegue of this forum said
that
NTP give nsec accurancy... Is impossible to have usec imagine nsec!
Thanks
If you have a GPS timing receiver (different from navigation
Rob wrote:
With NTP a single query does not affect the time so much, because
successive queries are fed through a filter to find the average, and
the time is not stepped but slowly changed to the new value. So when
there is an occasional delay in your network it will not affect the
time
Marcelo Pimenta wrote:
I thought that SNTP was used in a kind of Intranet with no routers and no
internet, so the low latency there is no need of so much calculations to
adjust the clock.
As W32Time is not fully NTP compliant, out of the box, it is probably
currently true that most SNTP use
On 2010-06-17, Marcelo Pimenta marcelopiment...@gmail.com wrote:
Yes, I agree. But we were talking about NTP using Ethernet, so... that's
impossible
Here's a snapshot of my main system showing an offset of 340us
(0.340ms) from it's sys_peer over a switched GigE LAN ...
remote refid
David Woolley da...@ex.djwhome.demon.invalid wrote:
SNTP as used on Windows to access the Microsoft timeserver certainly
can't. Anything that runs on Windows that sets the clock on ever
poll almost certainly can't for any reasonable application load. On
Linux you have to beware of interrupt
Steve Kostecke wrote:
On 2010-06-17, Marcelo Pimenta marcelopiment...@gmail.com wrote:
Here's a snapshot of my main system showing an offset of 340us
(0.340ms) from it's sys_peer over a switched GigE LAN ...
Which doesn't mean the error is .34 ms; it is quite likely less than
.1ms,
Marcelo Pimenta wrote:
2010/6/17 Richard B. Gilbert rgilber...@comcast.net
Marcelo Pimenta wrote:
Yes!! My question is about ms(MILIsecond) a collegue of this forum said
that
NTP give nsec accurancy... Is impossible to have usec imagine nsec!
Thanks
If you have a GPS timing receiver
2010/6/15 unruh un...@wormhole.physics.ubc.ca
On 2010-06-14, Marcelo Pimenta marcelopiment...@gmail.com wrote:
Hi everybody!!
My question is about Time Accuracy of NTP/SNTP protocol. I want to know
if
is possible to have precision of 1ms(could be 1 ms?) using SNTP in a
network with
Marcelo Pimenta marcelopiment...@gmail.com wrote:
The idea to have this is not overload the network asking time every second
to keep my accurancy in 1ms in 100% of time. And the second reason is about
how many ms your clock will be wrong in 59 sec without a frame to discipline
my clock again?
2010/6/16 Rob nom...@example.com
Marcelo Pimenta marcelopiment...@gmail.com wrote:
The idea to have this is not overload the network asking time every
second
to keep my accurancy in 1ms in 100% of time. And the second reason is
about
how many ms your clock will be wrong in 59 sec without
Marcelo Pimenta wrote:
Rob, my understading about the use of SNTP and NTP is: while SNTP provides
time synchronization within *one *network, NTP allows a global time
You are confusing it with timed. SNTP also expects to use global time,
and NTP can be used with an arbitrary timebase,
Marcelo Pimenta marcelopiment...@gmail.com wrote:
In my case, I have* only one* network. My Time Server is not a machine, is a
meinberg GPS. In my point of view, if my source time were machines, maybe
NTP could be better to find a middle line between all these machines used as
time servers.
Marcelo Pimenta marcelopiment...@gmail.com wrote in message
news:aanlktilq6m8apeoasibr-o8mhwifqkfv9xyf6mudr...@mail.gmail.com...
[...]
The NTP algorithm is much more complicated than the SNTP algorithm.
The short, short version: there is no SNTP algorithm. SNTP is NTP
_without_ the algorithms.
Marcelo Pimenta marcelopiment...@gmail.com wrote in message
news:aanlktilaoduniqjgpigohpzvjcv_zmsw_tr7naj6b...@mail.gmail.com...
[...] accuracy of 1ms. On a local network 100usec?? Even if we use
only switches(no routers), how is that possible if I have 4 types of
Latency increasing about
Hi everybody!!
My question is about Time Accuracy of NTP/SNTP protocol. I want to know if
is possible to have precision of 1ms(could be 1 ms?) using SNTP in a
network with 50 hosts(is the same with 100 hosts?) using only swithes, no
routing. All these hosts are syncronized with a Meinberg GPS.
On Mon, Jun 14, 2010 at 3:03 PM, Marcelo Pimenta
marcelopiment...@gmail.com wrote:
Hi everybody!!
My question is about Time Accuracy of NTP/SNTP protocol. I want to know if
is possible to have precision of 1ms(could be 1 ms?) using SNTP in a
network with 50 hosts(is the same with 100
On 2010-06-14, Marcelo Pimenta marcelopiment...@gmail.com wrote:
Hi everybody!!
My question is about Time Accuracy of NTP/SNTP protocol. I want to know if
is possible to have precision of 1ms(could be 1 ms?) using SNTP in a
network with 50 hosts(is the same with 100 hosts?) using only
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