"Daniel Havey" wrote in message
[]
So, you think that a PC clock will drift 20-50ms in 5 seconds? Seems
like a lot, but whatever. Let me see if I've got this right, you tell
me I might get say synchronization of ~10ms with ntpd running on a lan
with everybody on the same switch or perhaps on
Daniel Havey wrote:
> Wireless packets simply do not move that fast.
I would have guessed even 802.11a or g AP would be able to
reach a couple thousand packets per second, which could
result in sub-millisecond packet timing, and 802.11n AP
perhaps few hundred thousand packets per second resulti
Daniel Havey writes:
> ...but latency? On my control plane? No way ;^) That lan is s
> lightly loaded that any packet can get sent anywhere it wants at any
> time on Gigabit ethernet.
With Gigabit you may get erratic latency due to buffering and interrupt
coalescing.
> That might be a littl
> On its own no. With the help of ntpdate, yes. I
> wouldn't actually expect to reach this level very often, but
> I'd certainly expect several milliseconds. You will
> get these large steps because you are using individual
> measurements, which are very vulnerable to scheduling delays
> and net
Daniel Havey writes:
> So, you think that a PC clock will drift 20-50ms in 5 seconds?
No. We think that the network latency may jitter tens of milliseconds
in five seconds (especially on a busy network). Ntpdate will then
erroneously conclude that the clock is off and jerk it around. You are
tr
On Sep 17, 2010, at 2:21 PM, Daniel Havey wrote:
> So, you think that a PC clock will drift 20-50ms in 5 seconds?
Goodness, no, a typical PC quartz crystal has a frequency stability typically
measured in tens of PPM (ie, ~ 10E-5 to 10E-6); even a bad one ought to not
drift by as much as a millis
Daniel Havey wrote:
So, you think that a PC clock will drift 20-50ms in 5 seconds? Seems like a
lot, but whatever. Let me see if I've got this right, you tell me I might get
say synchronization of ~10ms with ntpd running on a lan with everybody on the
same switch or perhaps one switch away?
Now that's a little more like it ;^) Some real information. The experiments
involve hundreds of packets per second so 20,000 packets per hour is trivial.
Also lets drop the public NTP servers stuff, since I'm not using them and not
interested in doing so.
Of course they are not qualified to g
On Sep 17, 2010, at 10:58 AM, Daniel Havey wrote:
> Hmmm, I'm not sure that I believe you guys ;^)
So you've said before, and I've certainly gotten the impression that you would
prefer to make your own mistakes rather than heed advice about best practices.
> This is a wireless emulator on a wi
On 9/17/2010 10:58 AM, Daniel Havey wrote:
> My worst case occurs if the time is different between the computers.
It will be, perhaps nano seconds, perhaps mili seconds, ...
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It's almost like you didn't even read the last email. Perhaps you should
consider the application?
--- On Fri, 9/17/10, E-Mail Sent to this address will be added to the
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> From: E-Mail Sent to this address will be added to the BlackLists
>
> Subject: Re: [ntp:questions] Why
On 9/16/2010 6:12 PM, Daniel Havey wrote:
> But why would I want this script to point to someone else's ntp server?
They were just hoping you would not abuse others NTP servers
at that rate.
> The script was recommended by the manufacturer.
I think I would start looking for a much more knowledg
The machines are not VM.
Hmmm, I'm not sure that I believe you guys ;^) I don't think that my
application falls into the silly assumption "arrow of time" category. I don't
think there is any difference between a negative time step, and a positive one
(other than direction). Both are bad, but
> From: Steve Kostecke
> Date: 17 Sep 2010 12:34:35 GMT
> Sender: questions-bounces+oberman=es@lists.ntp.org
>
> On 2010-09-16, Daniel Havey wrote:
>
> > I want ntpdate, and don't really care about ntpd.
>
> Why? ntpd is both an ntp server and an ntp client.
>
> > I need an ntp server run
On 2010-09-16, Daniel Havey wrote:
> I want ntpdate, and don't really care about ntpd.
Why? ntpd is both an ntp server and an ntp client.
> I need an ntp server running on one node, and the other nodes connect
> to the first node with ntpdate ...
ntpd continuously disciplines the system clock
On 2010-09-16, Daniel Havey wrote:
> But no. No firewall, only iptables and there are no rules. Emulab
> sets up a VLAN between the two machines. So there are two CentOs 5.4
> machines connected to a switch, and there is a VLAN making this their
> own little world.
>
> Also I just talked to the E
I would like to know the answer to this question, because I have been seeing
the exact same problem with my RHL 5.2 machines.
-Original Message-
From: questions-bounces+steven.j.kelly=navy@lists.ntp.org
[mailto:questions-bounces+steven.j.kelly=navy@lists.ntp.org] On Behalf Of
"Daniel Havey" wrote in message
news:991491.24923...@web50302.mail.re2.yahoo.com...
Oh, yes of course.
It's CentOS 5.4 with the ntp from the distro:
[dha...@node2 /etc]$ yum list installed | grep ntp
chkfontpath.i386 1.10.1-1.1
installed
ntp.i386
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