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Topic: NTP sync frequency

I've had a report that a NION only syncs to NTP server at the moment the server URL is set in the Web Interface, but there is no indication in the log that it does at any other time.

When should it sync? Every minute, or? Maybe this would be obvious to someone who uses NTP regularly - but I don't.

Thanks,

"The single biggest problem in communication is the illusion that it has taken place."
                                                                                        - George Bernard Shaw

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Re: NTP sync frequency

A one-time synchronization that you describe would be useless as the clocks would just drift apart. NTP actively maintains synchronization between peers. The polling interval is actually variable. I'm assuming that the Nion uses a standard NTP implementation; here's a link from the NTP web page for additional information on the polling interval:

http://www.eecis.udel.edu/~mills/ntp/ht … .html#poll

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Re: NTP sync frequency

I agree that there's no point if it doesn't happen continuously (that's the point).

I've just had a look, using YATS32 to avoid having to fight with our corporate firewall at present.
The log (Verbiage) shows "Time sychronisation to server 192.168.100.29 ok" (that's my IP) when I set the server or change timezone in the Web Interface, but no indication of sync happening without intervention.
Is it that the log doesn't show it, or that it's not happening?
Thanks,
Phil

"The single biggest problem in communication is the illusion that it has taken place."
                                                                                        - George Bernard Shaw

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Re: NTP sync frequency

I'm not familiar with what YATS32 is, but the omnipotent Google declares it as some type of time sync software. I don't know what events cause it to make a log entry, but if you want the real story I would suggest heating up Wireshark and watching traffic from the Nion directed to UDP port 123 on the timeserver. Also take into account what provides time for this host running YAT32. If it doesn't have a source to 'real' time, you haven't gained anything by syncing your Nion to just another unsynchronized time source.

I would not expect changing the timezone to have any effect on NTP; NTP distributes UTC(universal coordinated time), which is the same all over the world. This is why computer clocks should be set to UTC and not local time. The OS then interprets this time based on the selected timezone for presentation to the user.

What battle do you have with the corporate firewall? A typical Nion NTP application should only require outgoing access to a small set of hosts on a single UDP port; no inbound access is required. Depending on the size of the facility, an IT department worth its salt probably already has a time source on their internal network available for private hosts. If nothing of that sort exists and they have a truly draconian firewall policy, there are a couple of ways to get real time for your Nions(and other NTP needy devices). You can run ntpd connected to a radio clock:

http://www.eecis.udel.edu/~mills/ntp/html/refclock.html

There are also several stand alone GPS based time servers available:

http://www.veracityglobal.com/products/ … menet.aspx
http://www.timetools.co.uk/ntp-servers/ … server.htm

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Re: NTP sync frequency

It's taken me a year to reconnect with this topic - sorry Jason.
I've had another report that NION systems apparently set up and accessing an appropriate NTP server in the institution are obviously not having time synced (as it drifts at the same rapid rate that stand alone NIONs do).
What I was looking for previously (with YATS32) was evidence in the NION log that a time sync was in fact happening. What I, and our customer, seem to see is that sync only happens while a human is poking around the web interface.

Is there any easy way to check that time sync from a server is actually happening?
Thanks

"The single biggest problem in communication is the illusion that it has taken place."
                                                                                        - George Bernard Shaw

6

Re: NTP sync frequency

Hi Phil-

Look in the Remote Log of the NION in question in NWare. After you enable polling for the NION(s) in question, right click in the Remote Log and choose "Filter". This is set to "note" by default. You want to switch it to "verbiage" instead. As you know, this filter shows (or does not show, depending on setting) messages according to the minimum severity setting.

You should see the message "Time set" as an entry in the Remote log indicating when that NION was syncronized with the rest. One node on your network should be configured as the "Time Server" and it should have the link to whatever time source you desire to use. Please have a look at this page in the help files: http://peaveyoxford.com/kc/index.htm#9016 It contains some very important information regarding how to configure a node on the network to contact an external time source.

Because of people complaining about the message "Time set" filling up their logs after a proper syncronization with NTP was implemented in the NIONs, the "Time set" message was downgraded to "verbiage" so it would not always be shown in the remote log. Every time the NION syncs with the master time clock on the network, there is a message in the remote log.

Please let me know if you have any additional questions.

Josh Millward
Burnt Orange Studios

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Re: NTP sync frequency

I've just done some further testing, and it appears that it's syncing at 6 hour intervals.
Have others observed this?
See the attached log segment. Note that at around 12:30 yesterday (2/13) I was setting date/time to wrong values, then going back to server so I could watch it sync. After that I left it alone, apart from a reboot.

Post's attachments

Attachment icon timeserver log.rtf 4.69 kb, 1162 downloads since 2012-02-14 

"The single biggest problem in communication is the illusion that it has taken place."
                                                                                        - George Bernard Shaw

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Re: NTP sync frequency

That "syncs" with what I know about Network Time Protocol.  (Get it, sync.  Ha ha).

Make it intuitive, never leave them guessing.

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Re: NTP sync frequency

The Nions will synchronise thier time when a Nion requests a time sync, i.e. at power up, or if someone has changed the time via the front panel or the web interface, and at 6 hourly intervals, as Phil found out.  All the Nions on the network send each other what they think the time is.  There is then an "election" to decide who has the right time.  A Nion set to timeserver will always win this election! If there is no time server then a Nion set to master will win.  If there are no clock masters or timeservers then Nions that have been recently powered up or had the time changed will be excluded from the election. The times from the remaining Nions are arranged in chronological order and then the median time value is taken as being the current Nion network time.  This rejects Nions that are very fast/slow.
Not that the protocol is SNTP not NTP which is also supported by NTP servers.

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Re: NTP sync frequency

Hi Graham,
Thanks for the official, and informative, answer to this.
Phil

"The single biggest problem in communication is the illusion that it has taken place."
                                                                                        - George Bernard Shaw