This Tech 2 Tech session provided information about network time services with varying levels of accuracy. The Janet NTP service was discussed which provides time accuracy of around 1 millisecond. More accurate services using PTP and White Rabbit that can achieve sub-microsecond accuracy were also presented. Examples of these services being deployed by other NRENs and organizations like Facebook were provided. The session aimed to discuss use cases for accurate network time, opportunities for new work, and whether Jisc should explore more accurate time services like PTP and White Rabbit. Attendees were invited to ask questions and provide thoughts on their network time requirements and needs.

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. #JiscSec
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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

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