Re: [ntp:questions] NTP autokey: self-signed certificate expiration problem

2017-12-29 Thread David L. Mills
Stephane lasagni wrote: Hello, I tried the NTP autokey protocol (TC scheme at first, then with IFF parameters - Schnorr algorithm since it is the scheme that is the most documented). I managed to get both schemes to work ok however I have noticed one problem: my product is a NTP client and

Re: [ntp:questions] NTP autokey and the "private certificate" scheme

2017-12-19 Thread David L. Mills
Stephane lasagni wrote: Hello, I apologize in advance if my questions further below seem basic to some of you: I am very new to NTP and Cybersecurity (a whole new world for me!). I am trying to work out out NTP autokey works when using the “private certificate” scheme, I thought you might be

Re: [ntp:questions] Understanding MJD in NTPv4 test cases

2012-08-17 Thread David L. Mills
antony, The NTP timescale described on the NTP Era and Era Numbering page at the NTP Project site reckonds JDN days and fraction since noon on the first day of year 4613. The correspondence betwen JDN day and civil year prior to Pope Gregory's bull is in JDN years of 365.25 days , as is the

Re: [ntp:questions] NTP vs RADclock?

2012-06-07 Thread David L. Mills
Julian, Thanks for the paper reference. Your ideas on feed-forward are similar to the ideas in Greg Troxel's MIT dissertation. These ideas were partially implemented in NTPv3 a very long time ago. There are some minor misinterptretations in the paper. The NTP discipline loop is not

[ntp:questions] Computer Network Time Synchronization: Russian translation

2012-04-26 Thread David L. Mills
Folks, I thought you might get a kick out of this. See www.eecis.udel.edu/~mills for ISBN number. Translated from the second edition, published by CRC Press. Dave ___ questions mailing list questions@lists.ntp.org

Re: [ntp:questions] Falseticker determination

2012-04-05 Thread David L. Mills
A C, Before you take a hacksaw to code, you should see the How NTP Works collection in the online documentation, in particular the clock select algorithm page. It includes advice on how to avoid falsetickers in cases like yours, including the use of tinker and/or tos commands. There should

Re: [ntp:questions] Off topic: using delay in routing protocols

2011-12-29 Thread David L. Mills
Juliusz , The fuzzballs indeed used a delay metric. They made little nests at the earth stations in the SATnet program, as well as the routers used in the early NSFnet. In its original form, the ARPAnet also used a a node state metric like the fuzzballs, but switched to a link based metric

Re: [ntp:questions] Choice of local reference clock seems to affect synchronization on a leaf node

2011-11-08 Thread David L. Mills
unruh, unhurt, 1. You have a broken interpretation on how the NTP discipline algorithm works. See the online document How NTP Works, and in particular the discipline and clock state machine pages. 2. Your

Re: [ntp:questions] Arcron (type 27) driver users needed

2011-09-23 Thread David L. Mills
Guys, Joe sent be a receiver and I have finally verified it works sorta. It took a couple of weeks before it found WWVB, but it did. I connected it to deacon for test. When it first came up ntpq reported it as working, but after a couple of minutes the driver aparently went into a loops and

Re: [ntp:questions] Magice Server Numbers: 4,5,7,9

2011-09-16 Thread David L. Mills
Danny, We would not be having this discussion if folks read how NTP works in the online documentation, in particular, the page on the select algorithm. The number of candidates is not limited to ten. By default, ten is the high water mark for survivors mobilized as preemptible in manycast

Re: [ntp:questions] Magice Server Numbers: 4,5,7,9

2011-09-16 Thread David L. Mills
Danny, We would not be having this discussion if folks read how NTP works in the online documentation. The maximum number of selectable candidates is not limited to ten. Ten is the high water mark for the number of preemptable candidates mobilized by the manycast and pool modes. Dave Danny

Re: [ntp:questions] how long does it take ntpd to sync up

2011-08-28 Thread David L. Mills
Brian, See the release notes for the latest distribution in the online documentation. There has been a bit of facebook engineering in this discussion. For the real story, see the How NTP Works pages in the latest online documentation. Dave Brian Utterback wrote: On 08/28/11 06:53,

Re: [ntp:questions] Setting back-up network servers to minpoll 10 automatically when sychronizied to a referrence clock.

2011-07-15 Thread David L. Mills
David, Something like this was done in NTPv3 (xntpd) and it turned out to be a bad idea. The poll interval is determined by the time constant, which for PPS and other low-stratum sources is relatively small. If a backup is switched in at a poll interval much larger than this, it takes awhile

Re: [ntp:questions] Controlling the combine algorithm

2011-07-04 Thread David L. Mills
the preempt phase. For configured associations, this number is irrelevant. Dave Steve Kostecke wrote: On 2011-07-02, David L. Mills mi...@udel.edu wrote: The combine algorithm operates on the survivors of the cluster algorithm, as described on the How NTP Works page. The number of survivors can

Re: [ntp:questions] Failure of NIST Time Servers

2011-06-04 Thread David L. Mills
Eugen , The remote NIST servers do not use the ACTS driver in the distribution. They use an algorithm called lockclock that functions as a modem device driver. I assume the unhealthy indication provided in the ACTS timecode is translated to the NTP LI indicator via the local clock driver, but

Re: [ntp:questions] Loop Filter Gains vs. Polling Interval

2011-05-16 Thread David L. Mills
Edward, The loop time constant varies directly with the poll interval. See How NTP Works in the current documentation. Note that the default value and range are purposely optimized for public time servers in order to manage network overhead and are not appropriate for the most accurate LAN

Re: [ntp:questions] ntp-keygen -H and update options

2011-05-13 Thread David L. Mills
Joe, The documentation is rather specific. If you generate a new host or sign key, the certificates are invalid and should be regenerated. Running ntp-keygen with now arguments generates a new certificate of the same type and signature as the existing one. Dave Joe Smithian wrote: Hi

Re: [ntp:questions] POSIX leap seconds versus the current NTP behaviour

2011-05-07 Thread David L. Mills
stamping. Dennis Ferguson On 5 May 2011, at 04:10 , David L. Mills wrote: Dennis, Holy timewarp! Are you the same Dennis Ferguson that wrote much of the original xntpd code three decades ago? If so, your original leapseconds code has changed considerably, as documented in the white paper

Re: [ntp:questions] POSIX leap seconds versus the current NTP behaviour

2011-05-04 Thread David L. Mills
Dennis, Holy timewarp! Are you the same Dennis Ferguson that wrote much of the original xntpd code three decades ago? If so, your original leapseconds code has changed considerably, as documented in the white paper at www.eecis.udel.edu/~mills/leap.html. It does not speak POSIX, only UTC.

Re: [ntp:questions] Bug 1700 - Clock drifts excessively at pollinglevels above 256.

2011-04-24 Thread David L. Mills
Edward, I don't know enough about the mechanism Windows uses to adjust the system clock. If some variant of the Unix adjtime(), the solution may be straightforward. The phase-lock loop parameters determine the risetime and overshoot of the discipline loop, in particular the loop gain and

Re: [ntp:questions] NTPD can take 10 hours to achieve stability

2011-04-18 Thread David L. Mills
C., It doesn't take ten hours; it takes five/ten minutes. See the online documentation release notes for recent NTP development versions at www.ntp.org. Dave C BlacK wrote: Why would it take ntpd ten hours to achieve its accuracy? Can this be explained in laymans terms and

Re: [ntp:questions] Help getting IRIG working

2011-04-02 Thread David L. Mills
Chris Co., The usual problem is overdriving the computer input.. Most IRIG devices produce a modulated signal in the range 10 V P-P, which is far larger than the line-in level. You might need an attenuator to produce in the order of 1 V P-P. As Chris says, the best way is to monitor the line

Re: [ntp:questions] Venting steam: Autokey in 4.2.6/4.2.7

2011-03-30 Thread David L. Mills
: On Tue, Mar 29, 2011 at 12:53 AM, David L. Mills mi...@udel.edu wrote: I sent you a message requesting to test this before deployment. I was referring to docs galore as I thrashed about earlier. I don't doubt each of your changes was an improvement, but each one also made

Re: [ntp:questions] new driver development

2011-03-30 Thread David L. Mills
reference to April Fool does not help when assessing your credibility. Dave Bruce Lilly wrote: On Mon, 28 Mar 2011 15:01:13 +, David L. Mills wrote: You may not be aware that all Spectracom devices are supported with one driver, all TrueTime devices are supported with one driver, all

Re: [ntp:questions] Venting steam: Autokey in 4.2.6/4.2.7

2011-03-29 Thread David L. Mills
wrote: On Tue, Mar 29, 2011 at 12:53 AM, David L. Mills mi...@udel.edu mailto:mi...@udel.edu wrote: I sent you a message requesting to test this before deployment. I was referring to docs galore as I thrashed about earlier. Â I don't doubt each of your changes was an improvement, but each

Re: [ntp:questions] Venting steam: Autokey in 4.2.6/4.2.7

2011-03-29 Thread David L. Mills
Miroslav, Unfortunately, while things were in flux, snapshots continued to be produced, which was counterproductive. I have no direct say in that. The best advice is: 1. Produce a working version of the configuration without Autokey. 2. Roll keys for all group members using ntp-keygen with

Re: [ntp:questions] new driver development

2011-03-28 Thread David L. Mills
Bruce Co., You may not be aware that all Spectracom devices are supported with one driver, all TrueTime devices are supported with one driver, all telephone modem services are supported with one driver, all Austron devices are supported with one driver, all Heath devices are supported with

Re: [ntp:questions] Venting steam: Autokey in 4.2.6/4.2.7

2011-03-28 Thread David L. Mills
Dave, When all else fails, read the documentation. There were good reasons to change the configuration in minor ways. 1. There was a huge vulnerability if the identity file was specified by the server, but the correct file was not specified by the client. The scheme devolved to TC with no

Re: [ntp:questions] Secure NTP

2011-03-24 Thread David L. Mills
Yassica, In principle, NTP Autokey can use certificates generated by OpenSSL or by other certificate authorities (CA); however, there are some very minor details with these certificates, including the sequence number and use of the X.500 extension fields. Ideally, the CA would run the Autokey

Re: [ntp:questions] new driver development

2011-03-17 Thread David L. Mills
Bruce, I take it your driver will replace or modify an existing driver, right? Adding a new driver to the current population of over 40 drivers is not a practical course. Dave Bruce Lilly wrote: I'm preparing a POSIX shared memory driver (PSHM) for ntp to address a few issues that exist

Re: [ntp:questions] Is a Spectracom Netclock/2 worth saving?

2011-03-11 Thread David L. Mills
Rick, All the Spectracom WWVB and GPS receivers use the same serial protocol; I have had one or more of these things running for almost 30 years. The Netclock/2 is useless without its ferrite-stick loop antenna, and even then the rising noise pollution due to the noisy electrical grid and

Re: [ntp:questions] AutoKey again

2011-02-04 Thread David L. Mills
Jacek, An index to the cryptic error comment is in ./include/ntp_crypto.h. It says bad or missing group key. This message is from the client; you should see the similar message at the server. Check to be sure you are using the correct client parameters file. Recent chjanges to the

Re: [ntp:questions] Number of servers needed to detect one falseticker?

2011-01-05 Thread David L. Mills
Terje, That's why Autokey uses digital signatures and zero-knowledge identity proofs. Dave Terje Mathisen wrote: David L. Mills wrote: Miroslav, Nowhere in the documentation produced by me is the statement that the minimum number of servers to reliably find the truechimers is four

Re: [ntp:questions] Number of servers needed to detect one falseticker?

2011-01-05 Thread David L. Mills
MIroslav, The select algorithm was changed in a very minor way to conform precisely to the formal assassin quoted in my previous message. It probably has very little practical significance. After all, the old algorithm has been going strong for nineteen years. Dave Miroslav Lichvar wrote:

Re: [ntp:questions] Number of servers needed to detect one falseticker?

2011-01-05 Thread David L. Mills
Terfe, Read the formal assertion carefully and examine the algorithm on the Select Algorithm page. The algorithm would return interval C as the smallest intersection with the largess number of contributors. Dave Terje Mathisen wrote: David L. Mills wrote: Miroslav, Nowhere

Re: [ntp:questions] Number of servers needed to detect one falseticker?

2011-01-05 Thread David L. Mills
Miroslav, According to your diagram, the algorithm would determine the intersection interval as interval a. The midpoints of all three intervals would be considered truechimers, since each of the intervals a, b and c, contain points in the intersection interval. Dave Miroslav Lichvar

Re: [ntp:questions] Number of servers needed to detect one falseticker?

2011-01-04 Thread David L. Mills
Miroslav, Nowhere in the documentation produced by me is the statement that the minimum number of servers to reliably find the truechimers is four. There might have been some confusion in the past, in particular with reference to Lamport's paper, which describes an algorithm much more

Re: [ntp:questions] Number of servers needed to detect one falseticker?

2011-01-04 Thread David L. Mills
David, As you might see from the online documentation, much of the tutorial material has been largely rewritten. Awhile back, some kind soul pointed out a logical discrepancy in the select algorithm. That was repaired, the code updated and the documentation refreshed. The pages linked from

Re: [ntp:questions] synchronization distance

2010-12-04 Thread David L. Mills
or worse than with SNTP.. Dave David Woolley wrote: David L. Mills wrote: BlackList, I say again with considerable emphasis: this is a Microsoft product, not the NTPv4 distribution that leaves here. What you see is what you get, But it is often NTPv4 reference version that is used

Re: [ntp:questions] synchronization distance

2010-12-04 Thread David L. Mills
with update intervals of a week will be as bad or worse than with SNTP.. Dave David Woolley wrote: David L. Mills wrote: BlackList, I say again with considerable emphasis: this is a Microsoft product, not the NTPv4 distribution that leaves here. What you see is what you get

Re: [ntp:questions] synchronization distance

2010-12-03 Thread David L. Mills
David, I'm confused about your explanation, especially the default configuration. The definitive explanation of synchronization distance, in particular your reference more precisely to root distance, is on the page How NTP Works in the online documentation at ntp.org. Dave David Woolley

Re: [ntp:questions] synchronization distance

2010-12-03 Thread David L. Mills
if the customer is satisfied with the performance. Just don't compare it with anything in the NTP distribution, documentation or specification. Dave E-Mail Sent to this address will be added to the BlackLists wrote: David L. Mills wrote: I had no idea somebody would try to configure

Re: [ntp:questions] help needed for ntpd ipv6 setup

2010-12-01 Thread David L. Mills
horhe, I can't speak to the versions used by other repackagers, but the current ntp-dev version interprets a nonzero broadest delay option as defeating the calibration volley for all broadcast and multicast clients. This is why it replaced the novolley option of the broadcast client command.

Re: [ntp:questions] Newbie question on the MD5 key of a public/remote NTP server.

2010-11-12 Thread David L. Mills
Harry, As I said, NTP Autokey is designed to operate outside the NAT perimeter. In principal, although I don't recommend it, it is possible to use symmetric key cryptography transparently with a NAT box. The policies on assignment and distribution of keys depend on the agency. NIST has an

Re: [ntp:questions] Will AutoKey setup work on a NAT host behind a firewall?

2010-11-10 Thread David L. Mills
to the internal network via a separate interface. Dave Harry wrote: On Nov 10, 2:59 am, David L. Mills mi...@udel.edu wrote: Harry, Autokey is not designed to work behind NAT boxes. The Autokey server and client must have the same (reversed) IP addresses. The intended model is using two interfaces, one

Re: [ntp:questions] Will AutoKey setup work on a NAT host behind a firewall?

2010-11-09 Thread David L. Mills
Harry, Autokey is not designed to work behind NAT boxes. The Autokey server and client must have the same (reversed) IP addresses. The intended model is using two interfaces, one for the Internet side running Autokey, the other for the inside net on the other side of the NAT box. Dave

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-09 Thread David L. Mills
is about 5 PPM low. Happy hunting, Dave Hart On Sun, Nov 7, 2010 at 00:58 UTC, David L. Mills mi...@udel.edu wrote: Dave, I think I have hunted down what is going on. It takes some serious investigation. Turns out the modern adjtime(), at least in some systems, is far from what I knew some years

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-08 Thread David L. Mills
presented with new ones. For that reason if no other, the mission to measure the intrinsic clock offset with large initial offsets is dead in the water. The source will be modified to entirely avoid all such initial training. Dave Dave Hart wrote: On Mon, Nov 8, 2010 at 05:14 UTC, David L. Mills mi

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-06 Thread David L. Mills
. The new code is in the backroom, but not yet a snapshot. Dave Dave Hart wrote: On Sat, Nov 6, 2010 at 03:34 UTC, David L. Mills mi...@udel.edu wrote: Now to the apparent initial frequency error. This is new, as tests in the past have not confirmed that. I need to plant some debug code

Re: [ntp:questions] calldelay syntax error ntp4.2.7p77 ?

2010-11-05 Thread David L. Mills
. They don't belong on the same web site. In any case, a prospective development user must first obtain the distribution, then read the release notes to see if it would be useful. At least, the release notes should be on the web site. Dave Steve Kostecke wrote: On 2010-11-05, David L. Mills mi

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-05 Thread David L. Mills
Dave, Further investigation continues; however, you have a fundamental misunderstanding of the slew limit in Soalris or any other BSD-semantics system. The slew is not a limit, it is an intrinsic constant equal to 500 PPM. The slew is implemented in this way. When adjtime() is called, it

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-05 Thread David L. Mills
Dave, We need some order here, as what you report with a pre-existing frequency file is quite dubious. Consider the two runs here, both with an existing frequency file and starting at both plus and minus 90 ms offsets: howland initial offset -91.7 ,s 55505 63959.804 -0.01000 -7.250

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-04 Thread David L. Mills
at 10:03:30PM +, David L. Mills wrote: I ran the same test here on four different machines with the expected results. These included Solaris on both SPARC and Intel machines, as well as two FreeBSD machines. [...] Ok, I think I have found the problem. The adj_systime

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-04 Thread David L. Mills
:33PM +, David L. Mills wrote: The daemon clamps the adjtime() (sic) offset to 500 PPM, which is consistent with ordinary Unix semantics. No, during that new fast phase correction on start it's not clamped to anything. That's the bug I'm hitting here. If 500 ppm is the standard rate

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-04 Thread David L. Mills
may have a different view, but the NTP implementation conforms to the traditional Unix semantics. Dave Miroslav Lichvar wrote: On Thu, Nov 04, 2010 at 08:32:06PM +, David L. Mills wrote: Wrong. The damon starts off be setting the frequency to zero, as you can see in the protostats. When

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-04 Thread David L. Mills
unruh wrote: On 2010-11-04, David L. Mills mi...@udel.edu wrote: Miroslav, The NTP daemon purposely ignores the leftover from adjtime(). To do otherwise would invite massive instability. Each time an NTP update is received, a new offset estimate is available regardless of past history

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-04 Thread David L. Mills
of 128 ms before the step kicks in. And yes, as reported several times, I have tested it with and without when the step is exceeded, but not with Linux. Dave ms/5 mini. Dave Hart wrote: On Thu, Nov 4, 2010 at 22:22 UTC, David L. Mills mi...@udel.edu wrote: Miroslav, IT IS NOT S BUG

Re: [ntp:questions] calldelay syntax error ntp4.2.7p77 ?

2010-11-04 Thread David L. Mills
BlackLists, The calldelay option is not mentioned in the master copy of the documentation that resides here. Sometimes there can be considerable delay for it to be published at ntp.org. Sorry about that, but I have no control over the publishing process. I am told the relevant documentation

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-03 Thread David L. Mills
, David L. Mills wrote: I ran the same test here on four different machines with the expected results. These included Solaris on both SPARC and Intel machines, as well as two FreeBSD machines. I tested with and without the kernel, with initial offset 300 ms (including step correction) and 100 ms. I

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-03 Thread David L. Mills
angst with the Linux semantics. Dave David Woolley wrote: David L. Mills wrote: I don't think that is right. The adjtime() call can be in principle anything, accoridng to the Solaris and FreeBSD man pages, but the rate of adjustment is fixed at 500 PPM in the Unix implementation. If the Linux

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-11-01 Thread David L. Mills
, even with the kernel enabled. You should see the frequency change in the loopstats. If not, try disabling the kernel to see if that is the problem. Dave, Miroslav Lichvar wrote: On Wed, Oct 27, 2010 at 11:55:22PM +, David L. Mills wrote: See the most recent ntp-dev. It needed some

Re: [ntp:questions] systems won't synchronize no matter what

2010-11-01 Thread David L. Mills
Mirslav, There is a very good reason. First, the kernel can an only be switched between PLL and FLL mode discreetly, while the daemon has a gradual transition between modes so that the poll interval can vary seamlessly between 8 s and 36 hr. Second, the kernel PLL is most useful to minimize

Re: [ntp:questions] peers using same server

2010-11-01 Thread David L. Mills
Miroslav, Depends on the synchronization distance. See the online page How NTP Works. Dave Miroslav Lichvar wrote: I've come across an interesting problem and I'm not sure if this is a bug or feature. When two peers are configured to use the same server as their source and the link between

Re: [ntp:questions] What level of timesynch error is typical onWinXP?

2010-10-25 Thread David L. Mills
the initial frequency file is in error something like 500 PPM, there will be a considerable additional time to converge. The model for this scheme is not to fix broken frequency files, but to quickly converge after a laptop has been off for a few hours. Dave David L. Mills wrote: Miroslav

Re: [ntp:questions] ntp orphan mode without manycast or multicast or broadcast ?

2010-10-14 Thread David L. Mills
Jerzy , See the online documentation at www.ntp.org. The release notes page has a link to a tutorial on orphan mode. Note the online documentation applies to the latest development version; the feature may or may not appear in the release versioin. Dave Miernik, Jerzy (Jerzy) wrote:

Re: [ntp:questions] GPS

2010-10-05 Thread David L. Mills
John, My experience with SA some years ago was that the timing accuracy was in the order of LORAN C, that is, about one microsecond. However, the oscillator in my Austron 2201 GPS receiver was disciplined in frequency by LORAN C, with result the timing accuracy was in the order of 50 ns. I

Re: [ntp:questions] Allan deviation survey

2010-09-16 Thread David L. Mills
. The intent is to avoid non-intersecting correctness intervals. Dave Dave Hart wrote: On Thu, Sep 16, 2010 at 1:23 AM, David L. Mills mi...@udel.edu wrote: Miroslav, The fastest machine I can find on campus has precision -22, or about 230 ns. Then, I peeked at time.nist.gov, which

Re: [ntp:questions] Allan deviation survey

2010-09-15 Thread David L. Mills
: On Tue, Sep 14, 2010 at 07:17:04PM +, David L. Mills wrote: Miroslav, Better recalibrate your slide rule. On a 2.8 GHz dual-core Pentium running OpenSolaris 10, the measured precision is -21, which works out to 470 ns. That probably just means the system on your machine

Re: [ntp:questions] Allan deviation survey

2010-09-14 Thread David L. Mills
in the distribution. Dave Miroslav Lichvar wrote: On Tue, Sep 14, 2010 at 02:45:01AM +, David L. Mills wrote: Don't get fooled by the MINSTEP. Precision is defined by the time to read the system clock at the user interface and I have never seen anything less than 500 ns for that, more typically 1000

Re: [ntp:questions] Allan deviation survey

2010-09-14 Thread David L. Mills
the criteria to judge performance, ntpdt would look 256 times better than advertised. I am not here judging whether chrony is better than ntpd or not, just that the performance measurements be comparable and honest. Dave unruh wrote: On 2010-09-14, David L. Mills mi...@udel.edu wrote

Re: [ntp:questions] Allan deviation survey

2010-09-13 Thread David L. Mills
the experiment with trace 3 and NTP operating at a poll interval of 16 s.. Dave Miroslav Lichvar wrote: On Fri, Sep 10, 2010 at 10:10:08PM +, David L. Mills wrote: A previous message implied that, once the Allan characteristic was determined, it would show chrony to be better than ntpd

Re: [ntp:questions] Allan deviation survey

2010-09-13 Thread David L. Mills
. Dave Miroslav Lichvar wrote: On Fri, Sep 10, 2010 at 08:48:58PM +, David L. Mills wrote: Miroslav, I've done this many times with several machines in several places and reported the results in Chapter 12 and 6 in both the first and second editions of my book, as well as my 1995 paper

Re: [ntp:questions] Allan deviation survey

2010-09-12 Thread David L. Mills
, and it servers no useful purpose. And, by the way, mail sent to your alleged mail address is returned to sender as undeliverable. Dave unruh wrote: On 2010-09-11, David L. Mills mi...@udel.edu wrote: David, With due respect, your comment has nothing to do with the issue. Allan deviation is between

Re: [ntp:questions] Allan deviation survey

2010-09-11 Thread David L. Mills
: David L. Mills wrote: Bill, Running a precision time server on a busy public machine with a widely varying load is not a good idea and I have no interest in that. Running As indicated by the sort of questions the group is getting recently, it is becoming the norm to run time servers

Re: [ntp:questions] Allan deviation survey

2010-09-11 Thread David L. Mills
I am concerned about and they are the ones the Allan deviation analysis is intended for. If you want to run NTP in a virtual machines, the performance will depend on many factors, but none of which have to do with Allan deviation. Dave David Woolley wrote: David L. Mills wrote: I beg

Re: [ntp:questions] Allan deviation survey

2010-09-10 Thread David L. Mills
Miroslav, I've done this many times with several machines in several places and reported the results in Chapter 12 and 6 in both the first and second editions of my book, as well as my 1995 paper in ACM Trans. Networking. Judah Levine of NIST has done the same thing and reported in IEEE

Re: [ntp:questions] Allan deviation survey

2010-09-10 Thread David L. Mills
Bill, All my measurements were in temperature-controlled environments, such as a campus lab or home office, and the data were collected over one week. The temperature varied less than a degree C. However, I have data from Poul-Henning Kamp for a similar experiment done in summertime Denmark

Re: [ntp:questions] Allan deviation survey

2010-09-10 Thread David L. Mills
David, I beg to differ. All the machines I used are PCs or similar workstations. They really and truly behave according to an exponential distribution with a small mean of a few to a few tens of microseconds. I have done a tedious histogram from which I can pick out the cache replacement,

Re: [ntp:questions] Allan deviation survey

2010-09-10 Thread David L. Mills
, it's from my book. However, there are examples in the Precision Time Synchronization briefing slides on the NTP project page at www.eecis.udel.edu/~mills/ntp.html. be advised, most of those briefings are from the 1990s. Dave unruh wrote: On 2010-09-10, David L. Mills mi...@udel.edu wrote

Re: [ntp:questions] [Pool] 4000 packets a second?

2010-09-01 Thread David L. Mills
how to fix this simple bug. Apparently, I never did get around to documenting the command other than an orphan reference on the rate management page. That's in process of fix. Dave Dave Hart wrote: On Wed, Sep 1, 2010 at 03:43 UTC, David L. Mills mi...@udel.edu wrote: Dave, The code I

Re: [ntp:questions] [Pool] 4000 packets a second?

2010-08-31 Thread David L. Mills
is contrary to the original intent and documentation. I didn't check to see if the probabilistic choice to preempt old entries if the list is full remains. My earlier experience is that this is important for the busiest servers. Dave Dave Hart wrote: On Wed, Sep 1, 2010 at 00:42 UTC, David L

Re: [ntp:questions] noise and stability values

2010-08-26 Thread David L. Mills
Jaap, Please see the Event Messages and Status Codes ant the ntpq pages in the documentation in your release. Dave Jaap Winius wrote: Hi folks, A few years ago I started graphing my NTP server's performance. The machine ran Debian lenny with ntp v4.2.4. However, after recently upgrading

Re: [ntp:questions] Q: No state variable in ntpd 4....@1.2089-o?

2010-08-13 Thread David L. Mills
Ulrich, The state variable was never intended to be externally visible. It has changed in many ways for many reasons. The variables designed for external monitoring are explicitly revealed in the documentation, in particular the ntpq page and the Event Messages and Status Words page.

Re: [ntp:questions] Advice for a (LAN-interconnected) WLAN Testbed w/ ARM nodes

2010-08-03 Thread David L. Mills
Guys, May I suggest you review the definitions of system offset (THETA), root distance (LAMBDA) and system jitter (PSI) in Section 11.2 of rfc5905. Dave David Woolley wrote: Miroslav Lichvar wrote: But there will be more clock updates. Noise in frequency may go up, but the offset will be

Re: [ntp:questions] Is a packet with stratum 1 allowed to contain a KoD code?

2010-07-25 Thread David L. Mills
Danny, KoD packets have the leap bits set to 3 (unsynchronized); the stratum is not signficant. The reference implementation sets the stratum to 16 for the RATE kiss code. However, packet stratum 16 is mapped to stratum 0 as visible to the monitoring function. Codes like INIT and STEP are

Re: [ntp:questions] Do logs indicate a config problem?

2010-07-16 Thread David L. Mills
Ulrich, From context I suspect Linux has incorporated the PPS kernel discipline code I wrote in the 1990s. That code has several provisions to groom noisy PPS signals, including a median filter, popcorn spike suppressor and range gate. Apparently, the PPS signal in this case is very noisy

Re: [ntp:questions] monitoring symmetric peers

2010-07-12 Thread David L. Mills
Kostas, Your symmetric peers have the same upstream system peer, so by rule they are not going to believe each other unless one of them switches to a different upstream source. Even if they have differerent upstream sources, one of them will not beleive the other, since that would create a

Re: [ntp:questions] SNTP with 1ms of precision?

2010-07-08 Thread David L. Mills
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

Re: [ntp:questions] Clock and Network Simulator

2010-07-01 Thread David L. Mills
engineering practice. This is the practice in the systems engineering course I taught over several years. You are invited to obstruct that practice to your own ends, but not in the public distribution. Dave Miroslav Lichvar wrote: On Wed, Jun 30, 2010 at 10:00:06PM +, David L. Mills wrote

Re: [ntp:questions] Clock and Network Simulator

2010-07-01 Thread David L. Mills
Miroslav, Exactly as expected. The overshoot exceeds the design limit of 10 percent by as much as 40 percent. That's exactly what the design is intended to avoid Dave Miroslav Lichvar wrote: On Wed, Jun 30, 2010 at 10:00:06PM +, David L. Mills wrote: The change in SHIFT_PLL would

Re: [ntp:questions] Clock and Network Simulator

2010-07-01 Thread David L. Mills
judgment. Dr. Dave Rob wrote: Miroslav Lichvar mlich...@redhat.com wrote: On Wed, Jun 30, 2010 at 10:00:06PM +, David L. Mills wrote: Is there somebody around here that understands feedback control theory? You are doing extreme violence to determine a really simple thing

Re: [ntp:questions] Clock and Network Simulator

2010-07-01 Thread David L. Mills
wrote: David L. Mills mi...@udel.edu wrote: Rob, With due respect, I don't think you know what you are talking about. Read it again. I don't question your design, I question your claims that the code implements the design which are upheld even when the contrary is shown

Re: [ntp:questions] Clock and Network Simulator

2010-06-30 Thread David L. Mills
Miroslav Lichvar wrote: On Tue, Jun 29, 2010 at 06:31:01PM +, David L. Mills wrote: From your description your simulator is designed to do something else, but what else is not clear from your messages. It might help to describe an experiment using your simulator and show what results

Re: [ntp:questions] Clock and Network Simulator

2010-06-30 Thread David L. Mills
Bill, The ntpdsim simulator uses the real system clock, which is modeled as the Allan variance. However, the server clock is modeled as a random-walk process computed as the integral of a Gaussian process. The network is modeled as an exponential distribution, although provisions have been

Re: [ntp:questions] Clock and Network Simulator

2010-06-30 Thread David L. Mills
David L. Mills wrote: Bill, The ntpdsim simulator uses the real system clock, which is modeled as the Allan variance. However, the server clock is modeled as a random-walk process computed as the integral of a Gaussian process. The network is modeled as an exponential distribution, although

Re: [ntp:questions] Clock and Network Simulator

2010-06-29 Thread David L. Mills
to describe an experiment using your simulator and show what results it produces. Dave Miroslav Lichvar wrote: On Mon, Jun 28, 2010 at 05:35:34PM +, David L. Mills wrote: How is your simulator different than the one included in the NTP software distribution? If I read the code

Re: [ntp:questions] Reference clock driver for /dev/rtc

2010-06-28 Thread David L. Mills
and the Autokey protocol will be unavailable. This is most important for NASA/JPL users when converting to and from UTC and TAI and eventually to TDB for deep space missions. Dave Miroslav Lichvar wrote: On Sat, Jun 26, 2010 at 03:07:33PM +, David L. Mills wrote: Another case in which

Re: [ntp:questions] Reference clock driver for /dev/rtc

2010-06-26 Thread David L. Mills
. Dave unruh wrote: On 2010-06-23, David L. Mills mi...@udel.edu wrote: Pavel, Linux has many, many times broken the NTP model compatible with other systems such as Solaris and FreeBSD, among others. I have no trouble with that as long as whatever modifications are required in NTP to make

Re: [ntp:questions] Reference clock driver for /dev/rtc

2010-06-26 Thread David L. Mills
Kalle, Calling settimeofday() is completely transparent to the kernel and ntpd state variables, including the UNSYNC bit; however, the actions in Linux might violate this design. Setting the RTC is a byproduct of settimeofday(), but in general setting the time to the current time is a no-op,

Re: [ntp:questions] Reference clock driver for /dev/rtc

2010-06-24 Thread David L. Mills
the NTP. Dave Krejci, Pavel wrote: Hello Dave, From: David L. Mills [mailto:mi...@udel.edu] Sent: Wednesday, June 23, 2010 4:42 AM To: Krejci, Pavel Cc: questions@lists.ntp.org Subject: Re

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