SANReN NTP Time Servers

Access Policy

Free and open to anyone.

Disclaimer: This service is done on a best effort basis, with reasonable effort to maintain a good quality NTP service. You use the service at your own risk and we accept no liability for its consequences. No guarantee about the availability or usefulness of the service is made.

If you abuse the sytem, we reserve the right to filter or rate limit your access.

Note: If you are synchronizing a lot of devices, it might be better to setup one or more of your own NTP servers, as depicted in the diagram. Configure only those to synchronize their time from NTP servers on the Internet. Then configure all your devices to use your own NTP servers.

Stratum 1 NTP servers

tick.sanren.ac.za
tock.sanren.ac.za
time-dev.sanren.ac.za (Used for development)
Note: All servers supports both IPv4 and IPv6.

Contact

john+ntp at sanren.ac.za

Performance and Usage Statistics

Over the last 3 days

Over the last 40 days

Over the last 400 days

Hardware

Supermicro SYS-110D-8C-FRAN8TP - 1U rack mount server
OCP TAP TimeCard v8 with:
- ALINX SoM AC7100B: XILINX Artix-7 XC7A100T Field Programmable Gate Array (FPGA)
- Global Navigation Satellite Systems (GNSS) receiver board using an u-blox NEO-M9N
- Oscillator board with SiTime SIT5721AC 10MHz 5ppb Digitally Controlled Oven Controlled Crystal Oscillator (DCOCXO)

Software

The TimeCard implements a counter in timespec format, that is made available on the PCI-Express bus. It synchronizes the counter to International Atomic Time (TAI), using the GNSS receiver and implementing two Proportional-Integral-Derivative (PID) controllers, called servos, one for the frequency and one for the offset or phase. This is all implemeted in the FPGA.

The TimeCard driver provides access to the card functionality and also implements a FreeBSD timecounter using the timecounters(4) API. It also makes the Pulse Per Second (PPS) signal available using the RFC2783 PPS API.

Created by John Hay,
Last edited: 2024-08-04