Time Appliances Project

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Welcome to the OCP Time Appliances Project wiki.
This Project is open to the public and we welcome all those who would like to be involved.
Time is one of the key elements to improve efficiency in a distributed system. Theoretically, the performance of a distributed system depends on the synchronization of its elements. Several industries such as telecom, mobile, power, industrial, professional audio and video and many more have embraced the need for highly accurate and more importantly reliable distribution and synchronization of time and frequency across packet networks. Although the use case scenario for each of the industries is different, they all share one common thing and that is, time synchronization. Since there is a diverse need for time synchronization across different industries, driven from different use cases and applications, managing the needs of this industry chain can become a challenge.

Time Appliances Project (TAP) aims to provide a platform to bring together the community, discuss, standardize and share technologies and solutions across industries with the datacenter applications and datacenter network infrastructure as the main interest. The project aims to bring together the community of datacenter operators, application developers, and equipment and semiconductor companies together to enable datacenter time-sensitive applications such as consistency in distributed systems, edge computing, AR/VR and IoT. These applications will greatly benefit from high accuracy, reliable, and scalable distribution and synchronization of time.

IEEE 1588 Precision Timing Protocol (PTP) and other synchronization methods have been adopted by various industries to maximize the efficiency of various distributed system use cases. Each use case scenario comes with a set of requirements and configurations. These configurations are collected as a ‘PTP profile’. Time appliances project aims to support the development of a PTP profile for datacenter applications and datacenter network infrastructure. The profile will cover time-sensitive applications over OCP-compliant and PTP-aware networking infrastructure such as network switches, network clocks, network interface cards, timing modules & connectors, etc. Additionally, the profile will address various requirements for high accuracy and reliable distribution and synchronization of time, such as expected performance, networking, software API, data models, deployment and telemetry. The project also aims at openness and interoperability through the use of open-source PTP software implementations for timing appliances.

IEEE P3335 Standard for Architecture and Interfaces for Time Card defines the generic architecture and interfaces of a time card system, which constitutes a traceable source of time-of-day to heterogeneous systems that distribute and/or use that time. Additionally, this standard defines figures of merit that univocally characterize the relevant performance of the Time Card. The Time Card provides a traceable time-of-day for systems directly attached to it, as well as networked distributed systems. Such systems include, but are not limited to, servers hosting the Time Card, and servers synchronized with the Time Card using such protocols as Precision Time Protocol (PTP) or Network Time Protocol (RFC Request for Comments) 5905). This standard also defines the basic building blocks of the Time Card and their interfaces in order to allow modularization. The main building blocks include time source, local oscillator, and time processor. Additionally, this standard defines interfaces between the Time Card and other systems. This includes physical interfaces that allow input and output of time-related signals. This also includes logical interfaces that are compatible with Portable Operating System Interface for UNIX (POSIX) and include for example an interface to share a Physical Hardware Clock (PHC). This allows sharing the time of day with other systems, as well as providing means for diagnostic and configuration. The definition of logical interfaces allows for a variety of Time Card's form factors (e.g. Peripheral Component Interconnect Express (PCIe)) while ensuring uniform support from the operating system. Any device that complies with this standard provides performance figures that are obtained following the specifications of this standard. As such, different implementations of the Time Card can be easily compared in terms of performance.

Datacenter applications are the primary target of time appliances project. In addition, the project extends to related topics on time synchronization in academia, research and other industries. The time appliances project brings together the community and will be highly collaborative through technical meetings and collaboration with other OCP Projects including the Networking, Storage, Server, and Telco Projects.

Disclaimer: Please do not submit any confidential information to the Project Community. All presentation materials, proposals, meeting minutes and/or supporting documents are published by OCP and are open to the public in accordance to OCP's Bylaws and IP Policy. This can be found on the OCP OCP Policies page. If you have any questions please contact OCP.

Mission Statement[edit]

1. Create specifications and references for Data Center Timing appliances, applications and networking infrastructure
2. Promote openness in Timing Appliances and interfaces through open-source implementations

Project Leadership[edit]

- Project Lead: Ahmad Byagowi, Ph.D. (OCP TAP | META)
- Incubation Committee: Elad Wind (OCP | NVIDIA)


Project Objective Lead Mailing List Status
#1 Time Card Development of the Time Card Ahmad Byagowi, Ph.D. Submitted
#2 Open Time Server Development of an open time server for DC and Edge systems Dotan Levi
Oleg Obleukhov
#3 Data Center PTP Profile Development of a PTP Profile tailored for data center applications Michel Ouellette Submitted
#4 Precision Time APIs Time APIs to disseminate the time error (error bound) and bring accurate time to the user space Georgi Chalakov OCP-TAP-APIs Submitted
#5 Oscillators Classification and measuring of oscillators Gary Giust, Ph.D. Submitted
#6 PTP Servos Design and Implement Advanced PTP Servos Alon Regev Work in progress
#7 Instrumentation and Measurement Open source instrumentation and measurement/testing tools for PTP Anand Ram
Julian St. James
Work in progress
#8 Precision Time Synchronization over Wireless Open source Implementations of Precision Time Synchronization over Wireless Nobuyasu Shiga, Ph.D.
Julian St. James
Work in progress
#9 Precision Time Measurement Readiness Status List of Hardware and Software with Precision Time Measurement Support Kevin Stanton, Ph.D.
Julian St. James
Work in progress
#10 Time Synchronization Industry-Academia workstream (TSIAW) Academic and Industry Engagement for Advancement of Precision Time Applications Dan Biederman
Hesham Albakoury
Work in progress

Get Involved[edit]

- TAP Mailing List
- OCP Projects Calendar
- Join TAP Discord server


- Charter
- TAP GitHub
- TAP LinkedIn
- TAP Facebook
- Google Drive Document Repository

Workstream Name Format Version Date
#1 Open Time Server Reference Architecture v1 July 28, 2021
Time Card Spec and design package v1 July 28, 2021
TAP Software Software v1 July 28, 2021
#2 Data Center PTP Profile Spec v2 November 3, 2022
v1 August 31, 2021
#4 Classification and Measuring of Oscillators Spec v1 January 8, 2022

Regular Project Calls[edit]

  • Wednesdays at 11am PST, starting on July 15th, 2020. Repeats every 2 weeks following that

Join the meeting from your computer, tablet or smartphone:

Dial in

  • +1 929 205 6099 US (New York)
  • +1 301 715 8592 US (Washington DC)
  • +1 312 626 6799 US (Chicago)
  • +1 253 215 8782 US (Tacoma)
  • +1 346 248 7799 US (Houston)
  • +1 669 900 6833 US (San Jose)

Upcoming Calls[edit]

Date Topics Speakers

#107 Aug-14, 2024 Hybrid Machine Learning Fusion Architecture for PNT Situational Awareness Stanley Radzevicius, Ph.D.
#106 Jul-31, 2024 Clocks and the Thermodynamic Limitations of Timekeeping Paul Erker, Ph.D.
#105 Jul-17, 2024 Race Conditions and Exactly Once Semantics In Distributed Systems Paul Borrill, Ph.D.
#104 Jul-3, 2024 Latest Trends in Crystals & Oscillators Madura Fontaine

Recordings from Past Calls[edit]


Index Date Topics Speakers Slides
#103 Jun-19, 2024 Synchronization Use Cases and Requirements for Data Center Network Liuyan Han, Ph.D. Slides
#102 Jun-05, 2024 A Façade of Newtonianism in Networking and it’s Consequences Paul Borrill, Ph.D. Slides
#101 May-22, 2024 Does Accurate Time Matter for Tasks that need Consensus? Ken Birman, Ph.D. Slides
#100 May-8, 2024 PTP: There at the Beginning John Eidson, Ph.D., Kang Lee, Doug Arnold, Ph.D. Slides
#99 Apr-24, 2024 Real-World Optical Timekeeping Marty Boyd, Ph.D. Slides
#98 Apr-10, 2024 Clock Coherence: from Terrestrial Microdatacenters to Interstellar Attoprobeswarms Paul Borrill, Ph.D. Slides
#97 Mar-27, 2024 The future of UT1 vs UTC Patrizia Tavella, Ph.D. Slides
#96 Mar-13, 2024 What is Time? Demetrios Matsakis, Ph.D. Slides
#95 Feb-28, 2024 Reliable, Fast Failure Detection with Deterministic Interactions in Datacenters Davide Rovelli Slides
#94 Feb-14, 2024 Precision Data Movement Dan Biederman Slides
#93 Jan-31, 2024 GNSS augmented sub-ns precision timing and 4 constellation NMA Roel de Vries Slides
#92 Jan-17, 2024 Let's talk Servos - Key to Synchronization Greg Armstrong Slides
#91 Jan-03, 2024 Precision Timekeeping Applications Discussion for Optical Atomic Clocks Judith Olson, Ph.D. Slides


#90 Dec-20, 2023 Atomic Clocks – Quantum theory in action for 80 years and counting David Chandler Slides
#89 Dec-06, 2023 5G PNT Using TV Transmitters Stefan Maier Slides
#88 Nov-22, 2023 Avnu Alliance: TSN Testing & Certification programs Dave Cavalcanti & Genio Kronauer Slides
#87 Nov-08, 2023 Pendulum: Sync your clocks with memory-safe NTP and PTP David Venhoek Slides
#86 Oct-25, 2023 Anomaly Detection in Raw GNSS Data Maksim Barodzka Slides
#85 Oct-11, 2023 ÜberNIC: an Ethernet Adapter with CXL and PTM Support Seth Friedman Slides
#84 Sep-27, 2023 Resilient Time Systems Robert Lindauer Slides
#83 Sep-13, 2023 Time in TigerBeetle Joran Dirk Greef Slides
#82 Sep-06, 2023 Precision Frequency Measurement over PCIe Julian St. James Slides
#81 Aug-30, 2023 Using Satelles LEO PNT to sync OCP-TAP applications Charlie Meyer Slides
#80 Aug-23, 2023 Precision Time in the Last Centimeters with PCIe PTM: A Deeper Dive Kevin Stanton, Ph.D. Slides
#79 Aug-16, 2023 PTP Track Hound v2 - Central Monitoring Hub for Timing-Critical Infrastructure Thomas Behn Slides
#78 Aug-02, 2023 Digital Time Services Judah Levine, Ph.D. Slides
#77 Jul-19, 2023 Quantum Time Transfer David Mitlyng Slides
#76 Jul-05, 2023 Secure Timing Architecture for Untrusted Edge Systems Fatima Anwar Ph.D. Slides
#75 Jun-21, 2023 The Network is The Clock: adding resilience at the network layer with vPRTC Christian Farrow Slides
#74 Jun-07, 2023 Brain's clock and Time Dissemination in the Body Oliver Rawashdeh, Ph.D. Slides
#73 May-24, 2023 Cultivating Trust In Time Ya-Shian Li-Baboud Slides
#72 May-10, 2023 Jamming and Spoofing of GNSS Timing Devices Thomas Rødningen Slides
#71 Apr-26, 2023 PTP-based fbclock vs. HLC Lu Pan Slides
#70 Apr-12, 2023 PTM Round Table L. Johnsen, K. Stanton, W. Wasko, B. Wheeler Slides
#69 Mar-29, 2023 COTS based Jitterbug Timing Measurement System Myrick Wilbur, Ph.D. Slides
#68 Mar-15, 2023 Integrated acoustic resonators in commercial Fin-FET technology Dana Weinstein, Ph.D. Slides
#67 Mar-01, 2023 Timing Resilience and Security at the Core of GNSS Technology Gustavo Lopez Slides
#66 Feb-15, 2023 Trading off Consistency and Availability in Cyber-Physical Systems Edward A. Lee, Ph.D. Slides
#65 Feb-01, 2023 SyncESMC - an ITU-T G.781 Multi-Clock ESMC Implementation Vipin Sharma Slides
#64 Jan-18, 2023 Overview of Timestamping and Synchronization Infrastructure at the Deutsche Boerse Georg Sauthoff, Ph.D. Slides
#63 Jan-04, 2023 Time & Frequency Measurements with Picosecond Streaming Time-to-Digital Converters Helmut Fedder, Ph.D. Slides


#62 Dec-21, 2022 Precision Timing for Digital Substations Fred Steinhauser, Ph.D. Slides
#61 Dec-07, 2022 G-SINC: Global Synchronization Infrastructure for Network Clocks Marc Frei Slides
#60 Nov-23, 2022 Enabling Pico-Second Level Space-Time Synchronization Nobuyasu Shiga, Ph.D. Slides
#59 Nov-09, 2022 Picosecond-Level Timing and Synchronization Jamil Abo-Shaeer, Ph.D. Slides
#58 Oct-26, 2022 The Current offerings of TCXOs, OCXOs and Rubidium Standards Kory Stone Slides
#57 Oct-12, 2022 Resilient PNT Standards for Datacenters Guy Buesnel Slides
#56 Sep-21, 2022 Resilient Time for the Future Leon Lobo, Ph.D. Slides
#55 Sep-07, 2022 White Rabbit for Datacenters Benoit Rat Slides
#54 Aug-24, 2022 Time Transfer Across the Network: One Hop at a Time Thomas Kernen, Nir Nitzani, Bar Shapira Slides
#53 Aug-10, 2022 Graham: Synchronizing Clocks by Leveraging Local Clock Properties Ali Najafi, Ph.D. Slides
#52 Jul-27, 2022 PTP Automation without Validation is just making mistakes faster Ariel Hendel Slides
#51 Jul-13, 2022 Window of Uncertainty Ahmad Byagowi, Ph.D. Slides
#50 Jun-29, 2022 GNSS Time References Christian Voit Slides
#49 Jun-15, 2022 Time Sync in Time Aware Networks Dhiman Chowdhury Slides
#48 Jun-01, 2022 Advanced TimeCard and SyncModule for datacenter synchronization Nir Laufer Slides
#47 May-18, 2022 GNSS Power over Fiber System Larry Conway Slides
#46 May-04, 2022 Optical Timekeeping Efforts at NIST Jeff Sherman, Ph.D. Slides
#45 Apr-20, 2022 Precision Time Applications Dan Biederman Slides
#44 Apr-06, 2022 Digitized Clocking Technology, Achieving Time Sync Inside and Across a Distributed a Systems Petre Minciunescu, Ph.D. Slides
#43 Mar-23, 2022 Opening the FPGA code of the Time Card Sven Meier & Thomas Schaub Slides
#42 Mar-09, 2022 Measuring and Monitoring Options for Time Sync Infrastructures Heiko Gerstung Slides
#41 Feb-23, 2022 A Continuous UTC; May We Get Rid of Leap Seconds? Patrizia Tavella, Ph.D. Slides
#40 Feb-09, 2022 Getting Precision Time Synchronization to End Users Julian St. James Slides
#39 Jan-26, 2022 Using LEO Satellites for Time Synchronization Tyler Reid, Ph.D. Slides
#38 Jan-12, 2022 Antenna Challenges for GNSS Receivers Daniel Suster Slides


#37 Dec-15, 2021 PCIe PTM: Timing in the Last Inch Christopher Hall Slides
#36 Dec-01, 2021 Application of Physical Layer Synchronization/Syntonization in a Data Center Environment Med Belhadj, Ph.D. Slides
#35 Nov-17, 2021 Oscillator Workstream Update Gary Guist, Ph.D. Slides
#34 Nov-03, 2021 Time Service for the Virtual Entity Dotan Levi
#33 Oct-20, 2021 Squared: A P2P Overlay Network for Setting up a Scalable PTP clock Synchronization Mesh Lasse Johnsen Slides
#32 Oct-06, 2021 Validating PTP follower clock accuracy Alon Regev Slides
#31 Sep-22, 2021 Transparent Clock and its Applications Amit Oren Slides
#30 Sep-08, 2021 Miniaturized Rubidium Oscillator With The Lowest SWAP Based on Double Resonance Christian S. Ph.D., Stavros M. Ph.D., Jean-Arnold C Slides
#29 Aug-25, 2021 Fearless Global Transactions using Clock Synchronization in CockroachDB Nathan VanBenschoten Slides
#28 Aug-11, 2021 White Rabbit High Accuracy Timing Francisco Girela Lopez, Ph.D. Slides
#27 Jul-28, 2021 Sundial: Fault-tolerant Clock Synchronization for Datacenters Gautam Kumar & Yuliang Li, Ph.D. Slides
#26 Jul-14, 2021 Holdover Challenges in NIC Based Boundary Clocks Eyal Cohen Slides
#25 Jun-30, 2021 GNSS Anti-Jamming and Spoof Mitigation Benoit Krummenacker Slides
#24 Jun-16, 2021 Introduction to IEEE1588-2019 Doug Arnold, Ph.D. Slides
#23 Jun-02, 2021 Introduction to MAC and CSACs Robert Lutwak, Ph.D. Slides
#22 May-19, 2021 Open Synchronization implementations on Linux/k8s Clusters Timo Jokiaho & Pasi Vaananen Slides
#21 May-05, 2021 White Rabbit: An Accurate Time and Frequency Transfer over Ethernet Maciej Lipinski, Ph.D. Slides
#20 Apr-21, 2021 Time Scale Ensembles in Uncertain Environments Marc A. Weiss, Ph.D. Slides
#19 Apr-07, 2021 Clock and Oscillator Statistics and Characterization Techniques Slides
#18 Mar-24, 2021 Introduction to Project Corundum for Time services Alex Forencich, Ph.D. Slides
#17 Mar-10, 2021 Oscillators Classification, Workstream #4 goals and kickoff Gary Giust, Ph.D. Slides
#16 Feb-24, 2021 GNSS Timing Samuli Pietila
#15 Feb-10, 2021 Centralized GNSS Monitoring and Assurance Nir Laufer Slides
#14 Jan-27, 2021 Huygens and its Applications Balaji Prabhakar, Ph.D.
#13 Jan-13, 2021 TAP 2020 Recap, 2021 Plans Ahmad Byagowi, Ph.D. Slides


#12 Dec-16, 2020 Chip Scaled Atomic Clocks John Kitching, Ph.D. Slides
#11 Dec-02, 2020 Data Center PTP Profile, Workstream #2 proposal Michel Ouellette
#10 Nov-18, 2020 Computer Timekeeping and Synchronization Kevin Stanton, Ph.D. Slides
#09 Nov-04, 2020 Time Sync in TSNs (History of TSN, IEEE 802.1AS Overview) Hesham ElBakoury Slides
#08 Oct-21, 2020 Starter's guide to ptp4l Maciej Machnikowski Slides
#07 Oct-07, 2020 Timing card implementation Ahmad Byagowi, Ph.D.
#06 Sep-23, 2020 Practical Use Cases of Synchronized Clocks Georgi Chalakov
#05 Sep-09, 2020 Data Center PTP Profile, Workstream #2 goals and draft spec Michel Ouellette
#04 Aug-26, 2020 Open Grandmaster (Open Time Server), Workstream #1 goals and draft spec Oleg Obleukhov
#03 Aug-12, 2020 TAP Vision as well as the impact of precision oscillator noise on PTP time error Dotan Levi
#02 Jul-29, 2020 Detailed Project Proposal and Discussion Michel Ouellette
#01 Jul-15, 2020 Proposal to launch OCP-TAP Incubation Project Ahmad Byagowi, Ph.D. Slides

Presentations & Events[edit]

- TAP Vision | Slides
- TAP Presentation | Slides

OCP Events

- 2023 | OCP Global Summit | TAP Track
- 2023 | OCP Regional Summit | TAP Track
- 2022 | OCP Global Summit | TAP Track
- 2022 | OCP Tech Talks | TAP Track
- 2021 | OCP Global Summit | TAP Track
- 2020 | OCP Tech Week | TAP Track


- 2021 GTC | Time Synchronization in Distributed Data Centers | Direct Video | Webpage | Slides


- Impact of Oscillator Noise on PTP Time Error by SiTime | Slides Part 1 | Slides Part 2

TAP Media References[edit]

- International Timing and Sync Forum 2022 interviewing Ahmad Byagowi
- "It's About Time (PTP on the Raspberry Pi)" video from Jeff Geerling Youtube Channel explains the effort on getting PTP on the Raspberry Pi
- "Why is this PCIe Card RADIOACTIVE?" video from Linus Tech Tips Youtube Channel highlighting the TAP Time Card
- "The most accurate Raspberry Pi clock IN THE WORLD! Can it do PTP?" video from Jeff Geerling Youtube Channel highlighting the TAP Time Card
- "Put An Atomic Clock in Your PC - Open Source Time Card" video from Gary Explains Youtube Channel explains the TAP Time Card
- "Facebook shares its Time Card atomic clock tech to speed internet services" article from C|Net
- "Supercharges Precision Timing for Facebook’s Next-Generation Time Keeping" developer blog from NVIDIA

References & External Links[edit]

- Spanner, TrueTime & The CAP Theorem by Eric Brewer, Google
- Sundial: Fault-tolerant Clock Synchronization for Datacenters by Google Inc. and Harvard University
- Practical Uses of Synchronized Clocks in Distributed Systems by Barbara Liskov
- Stanford Paper
- On Time Synchronization Issues in Time-Sensitive Networks with Regulators and Nonideal Clocks
- Accurate Network Clock Synchronization at Scale
- Exploiting a Natural Network Effect for Scalable, Fine-grained Clock Synchronization
- SIMON: A Simple and Scalable Method for Sensing, Inference and Measurement in Data Center Networks
- New Guidelines for Inclusiveness