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Session P2: PTTI Applications

Traceable UTC Time for the Finance Sector from NPLTime
Elizabeth Laier English, Conway Langham, Peter Whibberley, David Hicks, Simon Ashford, Leon Lobo, National Physical Laboratory, UK
Location: Regency B

The NPLTime service from the UK’s National Time Scale is fully operational and provides certified precise time to customers within the financial sector. The service is directly traceable to Coordinated Universal Time (UTC) and independent of GPS. Secure fibre optic links deliver the service, which is based on PTP version 2 (IEEE 1588 – 2008) and certified to be within +/- 1 microsecond of UTC(NPL).
Connection to NPLTime is available in datacentres in London, Reading and the surrounding areas. The main fibre infrastructure has expanded over the last year to include a number of datacentres along the M4 corridor to the west of London, where many financial firms have a presence due to the slightly reduced distance to the US and the resulting slightly lower latency for US trading.
The new European MiFID II regulation comes into force on 3rd January 2018, and requires all high-frequency trading participants to synchronise their business clocks to within ± 100 microseconds of UTC and timestamp algorithmic based trades with a granularity of 1 microsecond. The NPLTime service level agreement (SLA) of +/- 1 microsecond to UTC(NPL) at the customer endpoint aids firms in compliance with these regulations, and provides monitoring to validate service delivery. The customer endpoint is located in one of the datacentres where NPLTime is available, and connects to the service via fibre. The SLA of 1 microsecond to UTC(NPL) uses only 1% of the 100 us clock synchronisation to UTC error budget, rendering the remaining 99% to the customer for propagation through their own network to the point of the timestamp.
Recent customer data will be presented. Data collected from a customer endpoint during a calibration with a caesium clock demonstrates the performance of the service to be much better than the stated SLA. The customer’s time offset to UTC is of the order of 100 ns, which is typical of the performance achievable with PTP. This observed time offset is predominantly due to fibre network asymmetry. The stability of the customer’s equipment over the calibration period will be presented.
White Rabbit has been tested in our lab as a planned future upgrade from PTP for the primary fibre links in use by the NPLTime service, connecting NPL to datacentres in London Docklands and Reading. The onward distribution, managed by NPLTime’s partner Distributors, connecting to the customer endpoints and into the customer networks, will continue to be based on PTP v2. The sub-ns stability offered by White Rabbit provides a significant improvement on the 10 ns stability observed using PTP. Preparations are underway to install White Rabbit switches on the fibre link from NPL to Reading, where multiplexers are now in place on the fibre pair to allow both protocols to operate over different DWDM channels.



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