1.
Tech 2 Tech
What (Network) Time is It?
7 December 2022
Online
Tim Chown (Jisc) – tim.chown@jisc.ac.uk

2.
Agenda
• Introduction
• Jisc – Andrew Davis, Mark Rowley – the Janet NTP service
• NPL – Belinda Eglin - PTP and White Rabbit, and related activities
• GARR – Paolo Bolletta – White Rabbit field trial
• SURF – Sander Klemann – Proposed White Rabbit TFT service
• Q&A, discussion
• Future T2T events

3.
Introduction
Aim of this Tech 2 Tech session
• Provide information about our existing NTP service on Janet
• https://www.jisc.ac.uk/network-time-service-ntp
• Hear about other time services with higher accuracy
• Learn about what other NRENs are doing in this space
• Hear examples of what NPL is doing
• Discuss whether Jisc might provide additional services like other NRENs
• Discuss use cases for accurate network time
• Identify opportunities for new work and collaboration, or supporting network time research

4.
What are the use cases?
Examples – with varying requirements on accuracy
• Synchronisation between networked devices
• Improved accuracy for one way delay (OWD) measurements, e.g. using OWAMP
• Better correlation of logging information, esp. regarding security incidents
• Timestamping on a networked device
• Synchronised triggers in control systems
• Security protocols, certificates, DNSSEC, …
• Jisc as an NREN should also support network research, including in T&F services
• We can discuss these and others later in the session

5.
How do we get accurate network time?
“Accurate” varies…
• Network Time Protocol (NTP): RFC 5905
• Long-established, available on Janet over IPv4 or IPv6
• Open protocol, runs readily over existing IP network infrastructure
• Might achieve ~1ms accuracy (based on recent perfSONAR measurements)
• Precision Time Protocol (PTP): IEEE 1588
• Requires specific software/hardware support
• Can achieve well under 1 microsecond accuracy with hardware timestamping
• White Rabbit
• Designed at CERN - https://white-rabbit.web.cern.ch/, uses PTP extension (IEEE 1588-2019)
• Sub nanosecond accuracy
• Optical T&F
• Ultra precise / stable time and frequency signals transmitted over fibre optic networks

6.
Examples
More accurate time services being deployed…
• GÉANT GN4-3 project, NRENs
• Seeing PTP, WR and optical T&F (over C and L band) being deployed
• Updating perfSONAR statement on PTP - https://docs.perfsonar.net/ntp_overview.html
• Distributing new performant T&F services over NREN networks
• https://resources.geant.org/wp-content/uploads/2022/02/GN4-3_White-
Paper_Time_and_Frequency.pdf
• Management and monitoring of T&F services
• https://resources.geant.org/wp-content/uploads/2022/11/GN4-3_White-Paper_Management-
and-Monitoring-of-TF-Services.pdf
• Facebook / Meta and PTP
• https://engineering.fb.com/2022/11/21/production-engineering/precision-time-protocol-at-meta/

7.
Over to our guest speakers …

8.
Discussion time…
Your thoughts, questions?
• Is NTP enough for you?
• Is there anything we can do to improve the Janet NTP service for you?
• Do you have questions about the solutions presented today?
• Should Jisc follow other NRENs and explore PTP / White Rabbit?
• What are the use cases that are important to you, and what accuracy do they need?
• What future work or collaboration might we start?
• Anything else?

9.
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10.
Future sessions
• Janet Blog - https://shapingthefutureofjanet.jiscinvolve.org/wp
• Tech 2 Tech videos:
https://youtube.com/playlist?list=PLbKeiLya4JyBCnzdE6T1fJdZSfuFXeD_4
• Slack - https://join.slack.com/t/networkshop-community/shared_invite/zt-1f60iyr7n-
yJL031QZFpK85wMMRrMjLw (Link will be in slides!)
• Networkshop 51 – TBD
• The first Research Network Engineering community meeting, 2pm Fri 9 Dec
• https://beta.jisc.ac.uk/events/research-network-engineering-community-meeting
• T2T - https://www.jisc.ac.uk/get-involved/tech-2-tech
•“What’s new in the IETF” T2T, 8 Feb 2023
•Other dates in 2023 to be determined, let us know topics you’d like to see covered
Contact: Tim.Chown@jisc.ac.uk or Rob.Evans@jisc.ac.uk

11.
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