Re: [ntp:questions] NTP slow to start correction after a drift

2008-05-12 Thread Mike K Smith
Hi Brian, On 9 May, 19:06, Brian Utterback <[EMAIL PROTECTED]> wrote: > Do you have the frequency data from the same period as the graph? What > happened to cause the frequency to be off all of a sudden? Loopstats weren't enabled so I don't have the frequency data. I'm out of the office today but

Re: [ntp:questions] NTP slow to start correction after a drift

2008-05-12 Thread Mike K Smith
On 9 May, 16:46, Unruh <[EMAIL PROTECTED]> wrote: > Why would you use a solaris system? AFAIK its kernel timeing routines are > primative. Use a Linux/BSD system. This is an existing system which I don't have the means to change even if I felt that Solaris were somehow intrinsically inferior to Li

Re: [ntp:questions] frequency adjusting only

2008-05-12 Thread Maarten Wiltink
"Unruh" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > [... Delay] assumed to be symmetric and is already cancelled. The > ONLY way to really measure if there assymetry is to put a real clock > on each of the machines (Ie, a clock synchronized to usec accuracy to > UTC-- eg a GPS PP

Re: [ntp:questions] NTP slow to start correction after a drift

2008-05-12 Thread Richard B. Gilbert
Mike K Smith wrote: > On 9 May, 16:46, Unruh <[EMAIL PROTECTED]> wrote: > >> Why would you use a solaris system? AFAIK its kernel timeing routines are >> primative. Use a Linux/BSD system. > This is an existing system which I don't have the means to change even > if I felt that Solaris were someho

Re: [ntp:questions] NTP slow to start correction after a drift

2008-05-12 Thread David Woolley
Mike K Smith wrote: > Looks like I should be reducing maxpoll. I guess the design of NTP is As I understand it, the loop time constant determines the poll interval, but the poll interval doesn't constrain the loop time constant, so reducing maxpoll will not make the system significantly more re

Re: [ntp:questions] How does NTP calculate peer accuracy?

2008-05-12 Thread David L. Mills
Danny, You might recall the message that started the discussion was from a dude that wanted to selectively listen on one broadcast subnet but not another. I proposed to add a list of addresses to the broadcastclient command and include both original broadcast as well as multicast, just like th

Re: [ntp:questions] Dual Mixer Time Difference (DMTD) instruments sought

2008-05-12 Thread Joseph Gwinn
In article <[EMAIL PROTECTED]>, Joseph Gwinn <[EMAIL PROTECTED]> wrote: > I may need a Dual Mixer Time Difference (DMTD) instrument, to measure > picosecond changes in electrical length in a coax plus amplifier time > reference signal distribution system with total delays in the hundreds > of

Re: [ntp:questions] NTP slow to start correction after a drift

2008-05-12 Thread David L. Mills
David and others, The adaptive poll algorithm evolved over many years and many variations. A summary follows. 1. The poll will not be less than the maximum of the peer poll and minpoll. The maximum poll will not be greater than maxpoll. This is to protect the network. 2. The time constant wil

Re: [ntp:questions] Dual Mixer Time Difference (DMTD) instruments sought

2008-05-12 Thread David L. Mills
Joseph, I took a look at the instrument instruction manual to see what is going on. In typical todayspeak, Symmetricom doesn't say how the gadget works. I make it what used to be called a Costas direct-conversion receiver. The test signal is connected to two mixers; the reference oscillator is