Network architecture
We currently have three Symmetricom S300 NTP servers, each connected to a differential GPS antenna on the roof and each with a rubidium oscillator to provide a stable clock in the event of an issue with the GPS signal.
Each is capable of handling 7000 qps, and an explanation of how many clients they can support is given in Calculating NTP server load.
The two issues we have with these boxes are
- IPv4 and IPv6 cannot be configured on the same port and so we have used two ports where one would do on any normal kit.
- There is a remote vulnerability in the Autokey implementation so we cannot turn that on just yet
Synchronisation
The three servers are not synchronised to each other. They only use their internal GPS and rubidium oscillator as their time source.
Host names
The three servers are called ntp[1-3].ntp.net.nz. The host names that we ask you to access them by p[1-3].ntp.net.nz and s[1-3].ntp.net.nz are CNAMEs that we use to enable us to introduce more servers with different characteristics at a later stage without mucking people around. Rules on which names to use are given the in the Acceptable use policy.
Connectivity
ntp1 is in Albany connected via FX.
ntp2 is in Auckland CBD connected via ICONZ and directly into APE.
ntp3 is in Wellington CBD connected via FX and directly into WIX.
Software and Standards
As far as we know the software is the standard NTPv4 distribution which support the latest version of the NTP protocol (v3) and the Simple Network Time Protocol (SNTPv4).
Future plans
We are in touch with an NZ University that is developing a wire speed NTP server. When that eventuates we hope to add those servers as front ends to the current servers, taking a 1PPS signal from them, and possibly swap over the rubidium oscillators.
At some point we may buy more servers to add to the network. Three more would good but that is not high priority for us.
Ideally we would like a pair of active hydrogen masers, possibly five or more caesium clocks, a special basement to house them and a satellite dish for TWSTFT but given the cost of those we can only dream.
Have you looked at my proposal?
It probably needs some tweaks, but takes into account NZ’s ongoing problem with a lack of Stratum 1 servers.
http://hireme.geek.nz/NTP.html
PS:
Has anyone experimented with using the Moon for TWSTFT (Two-Way Satellite Time and Frequency Transfer)?
It’s free, and there are some frequencies set aside for EME transmissions.
Are you still running Symmetricom S300 boxes?
I was wondering if you were still running them because I too have open tickets with them about their IPv6 support. The most critical is the fact that when you enable IPv6 on an interface, it puts absolutely filtering on that interface. Anyone who knows the IPv6 address can connect to any open port on that interface unless something externally blocks it.
I’m also very frustrated that they seem incapable of getting this fixed even though it has been an open issue since April of this year.
I’d be interested in chatting more about your experiences with it if you don’t mind.