The Open Traceable Time Platform

and applications in finance and

telecommunications

Michael Wouters (NMIA)

Louis Marais (NMIA)

Amitava Sen Gupta (NPLI)

Ahmad Sahar bin Omar (NMIM)

Piyaphat Phoonthong (NIMT)

TCTF Workshop “Applications of T&F in finance and

telecommunications”, Singapore, 23rd November 2018

The Open Traceable Time Platform

www.openttp.org

A fully open platform for developing

time and frequency services with

timing signals traceable to national

standards

A complete hardware and software solution that aims

for a turnkey experience.

https://github.com/openttp

Why Open Source ?

Auditability Access to all system operational data,

at the level of raw measurements, to

prove that it was working correctly

Traceability Access to the full measurement and

analysis chain

Co-operation Leverage limited (and decreasing)

resources

Hardware and timing signals

GPS

receiver

time-interval

counter

GPS-

disciplined

oscillator

single board

computer

time of day

1 pps

NTP 1 pps

10 MHz1 pps

Single-board computer: BeagleBone Black

• 32 bit,1 GHz ARM processor

• dual 200 MHz realtime coprocessors

• 512 MB RAM

• running Debian Linux

GPS receiver: NVS NV08C-CSM

• GPS/GLONASS/Galileo

• 32 channel

• 2 UARTS

GPSDO: Jackson Labs LTE-Lite

When unlocked, and operated in an

environment where the temperature

is controlled to ±0.5 °C, the GPSDO

drifts by about 1 ms over 5 days.

TCXO

FPGA: Opal Kelly XEM6001

USB interface

TICS are 200 MHz counters so

only 5 ns resolution.

Potential to improve this

Stability and accuracy of time-transfer

splitter

Septentrio

PolaRx4TRPRONVS NV08C

UTC(AUS)

TIC

1 pps

1 pps10 MHz

Stability of the computer’s time

GPSDO timestampGPIO

1 pps

/dev/pps0

ntpd disciplining

time constant (16s)

Accuracy of the computer’s time

GPSDO IRQ raisedGPIO

1 pps

IRQ handler called

system time

requested for

timestamp

about 5 µs

NTP load testing

PC

OTTP

direct connectiont

40,000 pkt/s

0

pac

kets

/s 8000 pkt/s

Use ntpd’s remote management facilities to gather statistics

ntpd becomes unresponsive and statistics can no longer be collected

Response of the system to a step increase of 104

packets/s in the NTP load

on off

Application: traceable time of day for telecomms

charging and billing systems

TelecommunicationsAustralian Communications Industry Forum Code of Practice:ACIF C518:2006 Call charging and billing accuracywww.acma.gov.au

Tolerance levels – Billing accuracy Parameters

Billing accuracy Test call tolerances

Parameter Untimed Timed

Call start time error +8.5,-5.5 s +8.5, -5.5 s

Call duration error n/a +1.5,-2.5 s

(from Table 3.1, pg 10)

Application: auditing of NTP time of day

OTTP

time server

time server

time server

Customer may already have existing NTP infrastructure for their network.

Advantages of auditing rather than direct provision of time:• not a critical piece of infrastructure• change management is simpler• less complicated management software• less risk !

NTP

NTP exchange

T1

T2 T3

T4

unit under test

auditing system

mean offset = [(𝑇2 − 𝑇1) + (𝑇3 − 𝑇4)]/2

round trip time = 𝑇4 − 𝑇1 − (𝑇3 − 𝑇2)

The uncertainty in the mean offset is half of the round trip time

Other information available –NTP stratum, accuracy, leap second indicator

NTP measurements on a LAN

Audited system is a GPS-referenced NTP appliance

Required synchronization accuracies

Gateway to gateway latency UTC accuracy Timestamp precision

> 1 ms 1 ms < 1 ms

<= 1 ms 100 µs < 100 µs

MiFID II requirements (European Union)

9.3.1 Market operators to synchronise clocks

(1) A Market operator must set the clock the Market operator uses for recording the time and date in its trading, compliance monitoring and reporting systems so that it is synchronised to within 20 milliseconds of the UTC(AUS).

(2) Where a Market operator relies on another person to provide any aspect of their trading, compliance monitoring or reporting systems that records the time and date, the Market operator must take reasonable steps to ensure that person synchronises the clock used for that purpose to within 20 milliseconds of the UTC(AUS).

ASIC requirements for financial markets (Australia)

Department of Industry, Innovation and Science | National Measurement Institute

36 Bradfield Rd

Lindfield NSW 2070

Australia

Telephone +61 2 8467 3501

Thank you for your attention!