ntpMerlin ntpMerlin - NTP Daemon for AsusWRT Merlin

[L&LD]

If NTP over the Internet can only synchronize to the single milliseconds at best, then what would be the benefit of your access to an atomic clock?

We won't know until we try it.

On routers that I have left on for more than a few days without 'playing' with them (scripts!), I have seen 32 u for offset. That is from a stratum one NTP server within the city (based on GPS).

 

[L&LD]

Jack Yaz, forgot to previously report that the RT-AC3100 running RMerlin 384.10_2 is also one of the 'supported' routers now and has been working great for a few days already.

 

[cmkelley]

I don't think we (as in average joe) will ever get access to the atomic clocks used all around the world as the 'reference').

But can you imagine the fun we could have, though?

Actually, you do have access to the atomic clocks. The clock itself is Stratum 0, so a Stratum 1 server is the time server for that clock - it translates the frequency pulse that the clock gives off into a timestamp that can be served over the network. Something has to take the pulses from the atomic clock and turn it into time that we can use. A Stratum 0 clock is a frequency generator. Having direct access to it wouldn't help you much. You can buy your own rubidium frequency source for ~$1,500 to $5,000 or your own cesium frequency source for ~$25,000. The ntp program can take the frequency from that, along with time information from other Stratum 1 servers, and turn that into your very own Stratum 1 server. But that will still be a Stratum 1 server.

Don't forget, the number of seconds in a year isn't constant (it isn't even a linear decay), but an atomic clock doesn't know anything about the rotation of the earth. So all the Stratum 1 servers have to talk to each other and agree what time it is. Occasionally leap seconds are introduced to account for variations in earth's rotation and orbit. If we just defined a year as a set number of seconds and let the clocks run independently of each other (they would in fact keep perfect time with each other), you'd eventually find that the time of day no longer really corresponds to a sun position in the sky.

 

[JDB]

Actually, you do have access to the atomic clocks. The clock itself is Stratum 0, so a Stratum 1 server is the time server for that clock - it translates the frequency pulse that the clock gives off into a timestamp that can be served over the network. Something has to take the pulses from the atomic clock and turn it into time that we can use. A Stratum 0 clock is a frequency generator. Having direct access to it wouldn't help you much. You can buy your own rubidium frequency source for ~$1,500 to $5,000 or your own cesium frequency source for ~$25,000. The ntp program can take the frequency from that, along with time information from other Stratum 1 servers, and turn that into your very own Stratum 1 server. But that will still be a Stratum 1 server.

Don't forget, the number of seconds in a year isn't constant (it isn't even a linear decay), but an atomic clock doesn't know anything about the rotation of the earth. So all the Stratum 1 servers have to talk to each other and agree what time it is. Occasionally leap seconds are introduced to account for variations in earth's rotation and orbit. If we just defined a year as a set number of seconds and let the clocks run independently of each other (they would in fact keep perfect time with each other), you'd eventually find that the time of day no longer really corresponds to a sun position in the sky.

So, Stratum 1 servers use the principal of a quorum to agree the LST (Local Solar Time) at the Greenwich Meridian. Quite an elegant solution!


Sent from my iPhone using Tapatalk

 

[JemTheWire]

If I install this script on my router, do I also need to install it on my Access Point as well? Also, I have a lot of 'Smart Plugs', Philips Hue lights etc. Do they get their time from the router or are they hard coded to use a remote NTP server?

I am a little confused, as you may gather, as to what actual benifit I would get from this.

I do love tinkering and the fancy graphs though!

 

[L&LD]

If I install this script on my router, do I also need to install it on my Access Point as well? Also, I have a lot of 'Smart Plugs', Philips Hue lights etc. Do they get their time from the router or are they hard coded to use a remote NTP server?

I am a little confused, as you may gather, as to what actual benifit I would get from this.

I do love tinkering and the fancy graphs though!

No, just install on your main router.

If you enable the option for your clients to use it, then not only will they be synced with the router, you are saving a few bytes of bandwidth too by having just one device (the router) go out to an NTP server instead of every single device on your whole network.

Highly recommended!

 

[JemTheWire]

Next question.

How do I enable the option for my client devices to use it?

EDIT:

So sorry, realised it was an option in the installation menu. It's been a long day. Caffine required.

 

[visortgw]

Either enable the option to force all NTP requests to be handled by the router, or specify the router IP as the NTP server for each client.

Next question.

How do I enable the option for my client devices to use it?

EDIT:

So sorry, realised it was an option in the installation menu. It's been a long day. Caffine required.

You can also specify router IP as the NTP server for each client.

 

[cmkelley]

Either enable the option to force all NTP requests to be handled by the router, or specify the router IP as the NTP server for each client.

You can also specify router IP as the NTP server for each client.

Right, but the reason that option is there is because some devices have hardcoded ntp servers in their firmware.

 

[QuikSilver]

Single server users seem to be getting 0 jitter - I don't know enough about ntpd to know if that's expected though, sorry

Added a second and jitter showing now, thanks.

 

[John Fitzgerald]

they're generally funded by the taxpayers. I would assume in the US, the Navy would have one accessible; in every country, there should be ONE that some branch of the government maintains...

tick.usno.navy.mil
tock.usno.navy.mil

 

[Swistheater]

so when I enable this to intercept NTP does that mean i do not need to configure any NTP settings on devices like computers that serve up NTP via internet address?

 

[L&LD]

so when I enable this to intercept NTP does that mean i do not need to configure any NTP settings on devices like computers that serve up NTP via internet address?

No, it means that they will not go out individually to the internet NTP server to get the proper time. This will make the clocks on all client devices essentially identical as the 'clock' is within the LAN.

 

[Swistheater]

so like say for an example a windows computer that is told to get its time from the internet via time.windows.com---- the router will catch this and inject its time instead?

 

[L&LD]

so like say for an example a windows computer that is told to get its time from the internet via time.windows.com---- the router will catch this and inject its time instead?

Yes, that is my understanding.

 

[Swistheater]

so I ran w32tm /stripchart /computer:192.168.1.1 /dataonly /samples:15 in my command prompt
this is my results:

it seems like there is an error response every so often any advice?

 

[Swistheater]

I did however change the ntp server to 192.168.1.1 on the computer clock and ran w32tm /resync
I got pretty interesting results. then I changed it to something else and got failure results :

 

[Centrifuge]

Don't forget, the number of seconds in a year isn't constant (it isn't even a linear decay), but an atomic clock doesn't know anything about the rotation of the earth.

Or time dilation due to gravity, distance from the Earth's core and orbital speed.

 

[Jack Yaz]

Quick question, anyone here running firmware version 384.6 or earlier?

 

[Jack Yaz]

so I ran w32tm /stripchart /computer:192.168.1.1 /dataonly /samples:15 in my command prompt
this is my results:
View attachment 16919
it seems like there is an error response every so often any advice?

This appears to be "limited" in action:

limited
These hosts are subject to limitation of number of clients from the same net. Net in this context refers to the IP notion of net (class A, class B, class C, etc.). Only the first client_limit hosts that have shown up at the server and that have been active during the last client_limit_period seconds are accepted. Requests from other clients from the same net are rejected. Only time request packets are taken into account. Query packets sent by the ntpq and ntpdc programs are not subject to these limits. A history of clients is kept using the monitoring capability of ntpd. Thus, monitoring is always active as long as there is a restriction entry with the limited flag.

@EmeraldDeer do we need limited on the LAN?