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NTP Polling Frequency

‎10-07-2018 03:31 PM

I have had my SRX setup to use an NTP source for a while and for the most part, works just fine. Every now and then I notice that the time seems to drift a bit more than I think it should given that the source is literally connected to the SRX - both are connected to an unmanaged switch. The offsets that I have seen range from -2 to -15 which to me seems very high given the proximety to the source - which is a RPi with a GPS puck.

 

I also noticed the poll rate is set to 10 which equates to 1024 seconds. Probably not bad as it keeps the chatter down but maybe less than 17 minutes would minimize the drift? If so, how do you change it as there is not option from the configuration to change the polling interval.

 

Why do I care? Well, everything else on the network points to their gateway for the primary time which is the SRX so I'd like it to be as accurate as possible - also why I build the RPi/Stratum 1 time source.

 

Appreciate any thoughts/suggestions you guys may have.

4 REPLIES 4
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Re: NTP Polling Frequency

‎10-08-2018 08:27 AM

Hello,

 

Is the SRX in standalone more of cluster?

Also can you share the output of command 'show configuration system ntp' as well as output of 'show ntp status' & 'show ntp association' when a) you see a drift & b) when yo do not see drift?

 

Regards,

 

Rushi 

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Re: NTP Polling Frequency

‎10-08-2018 08:38 AM

It is a single SRX-210

 

[root@GreatGazoo> show configuration system ntp |display set

set system ntp server 10.20.15.172

set system ntp server 10.20.15.210 prefer

 

[root@GreatGazoo> show ntp status

status=06f4 leap_none, sync_ntp, 15 events, event_peer/strat_chg,

version="ntpd 4.2.0-a Sat Dec 23 10:42:44 UTC 2017 (1)",

processor="octeon", system="JUNOS12.1X46-D72.2", leap=00, stratum=5,

precision=-17, rootdelay=14.785, rootdispersion=66.811, peer=5781,

refid=10.20.15.210,

reftime=df65f0ef.42460141  Mon, Oct  8 2018 15:06:23.258, poll=10,

clock=df65f77e.47598541  Mon, Oct  8 2018 15:34:22.278, state=4,

offset=-6.241, frequency=16.447, jitter=4.115, stability=0.105

 

root@GreatGazoo> show ntp associations

     remote           refid      st t when poll reach   delay   offset  jitter

==============================================================================

+barney.cpt-laba 10.20.15.210     5 -  682 1024  377    3.360    1.057   5.704

*10.20.15.210    PPS(0)           4 -  659 1024  377    3.121    0.024   6.266

 

Like I said, I check it now and again and just trying to figure out if the drift is due to the fact that it polls the source every 17 minutes (interval setting of 10=1024 seconds) and if there is a way to change that?

 

Thanks!!

 

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Re: NTP Polling Frequency

‎05-16-2019 05:46 AM

Yes this is an old post but I'm still struggling with finding a sollution. Any suggestions? And yes I realize the srx-210 is end of life but hey, if it ain't broke 🙂 And it's just running my home network.

 

Thanks!

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Re: NTP Polling Frequency

‎06-03-2019 11:51 PM

Hi,

When you say the time is drifting, are you seeing a large time difference between the ntp server and the ntp client ? Why are you looking at modifying the polling time? Ntp will choose the polling time dynamically depending on the network conditions. If you are seeing polling times settling at 1024, then the problem could be somewhere else.

 

Thanks

John

 

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