White Rabbit Standardization in IEEE1588-2008

The White Rabbit extension of the IEEE1588-2008 standard is being generalized into a text of the upcoming release of the standard. This process is now in the final stage and it is due to finish around 2018, publication of the standard in 2019. Once finished, the generalized White Rabbit (under the name High Accuracy) will be the third default PTP Profile included in Annex J of the IEEE1588.
This wiki page provides details regarding the White Rabbit extension and its standardization in IEEE1588.

Introduction

White Rabbit* (WR) is an extension of the IEEE1588-2008 (Precision Time Protocol, PTP) standard. The WR extension has been developed to synchronize nodes in a packet-based network with sub-ns accuracy. Achieving such high accuracy results from the combination of IEEE1588-2008 (Precision Time Protocol, PTP) with the following further extensions:

clock syntonization over the physical layer (similar to SyncE),
enhancement of timestamps precision through phase detection,
automatic precise evaluation of link asymmetry.

White Rabbit evolved into an extension of the Precision Time Protocol (PTP) and is therefore referred to as WRPTP.
WRPTP is fully compatible with PTP and is currently being defined as a PTP Profile.*

The solutions in WRPTP are now being included by the P1588 Working Group in the next revision of the PTP standard.

White Rabbit Specification (WR Spec)

The White Rabbit Protocol is defined in the White Rabbit Specification (WR Spec) that describes:

hardware requirements for implementing WRPTP
protocol requirements for WRPTP-compatibility

White Rabbit Specification material

WR Specifications
- WR Specification - latest version
- older versions of the WR Specification (to show how the WR Spec evolved)
short information regarding different versions (i.e. feedback, comments, diffs)
issues and possible improvements to the current version

Standardization benefits and paths

Standardizing White Rabbit is unquestionably beneficial to the project and its users and is expected to bring a substantial boost to the number of WR applications.

Advantages of standardization:

easier co-operation with companies
increase of stability, viability, and credibility of the White Rabbit solution
feedback of experts that enables to polish the solution and make it more mature

Standardization is a considerably long process that can be approached in various ways and from various directions. Potential paths (see presentation) for WR's standardization had been identified. These included:

Standardization at the International Telecommunication Union- Telecommunication Standardization Sector (ITU-T)
- within Telecom Profile (G.827x) - currently being developed
- as a separate Profile (similar to Telecom)
Standardization at the Institute of Electrical and Electronics Engineers (IEEE)
- as an IEEE1588 PTP Profile
- included into version 3 of PTP (PTPv3) (this is the chosen way of WR standardization)
- as a part of AVB Gen2, included in updated 802.1AS
Standardization within another standardization body/consortium

White Rabbit standardization within the IEEE1588 revision process

Including White Rabbit into the IEEE1588 (PTP) standard has been identified as the best and feasible WR standardization path.
White Rabbit was proposed to be included into PTP as a High Accuracy Option/Profile (presentation, document) at the Special Session of ISPCS2012. This Special Session showed an interest and need for reasonably broad IEEE1588 revision. The first step in revising PTP was the preparation of Project Authorization Request (PAR) by a Study Group at the beginning of 2013. The PAR states that the revised protocol "enhances support for synchronization to better than 1 nanosecond" which reflects the enthusiasm of the group to evaluate White Rabbit extensions.

The revision process of the IEEE1588 Precision Time Protocol (PTP) standard started in mid-2013. The revision work is done by the P1588 Working Group, which consists of over 180 members from all over the world representing industry and science, including CERN. The Working Group is arranged in 5 sub-committees focusing on different aspects of the PTP revision, namely: Architecture, Management, Upkeep, Security and High Accuracy Enhancements. The High Accuracy sub-committee is lead by CERN representative. It is dedicated to generalizing White Rabbit solutions to a broader range of applications and including these generalized solutions in the IEEE1588 standard.

P1588 Working Group
- P1588 Subcommittee High Accuracy: Co-chairs: John MacKay (Progeny Systems Corporation) and Maciej Lipinski (CERN). Sec/Editor: Geoff Garner (Consultant for Huawei Technologies Co., Ltd.)

IEEE1588-2008 standard, available through IEEE Explore Digital Library (payable)
- The draft upcoming standard is not available to people outside the Working Group.
What’s coming In the Next Edition of IEEE 1588?, Douglas Arnold, Sept 2017
The New High Accuracy Default PTP Profile in the IEEE 1588 Draft Revision, Maciej Lipinski, ISPCS2019, Sep 2019

Goal of this project

The goal of this project is to standardize the White Rabbit Protocol.

Project plan

Evaluation of standardization path/method
1. _White Rabbit Standardization Group_ established to help in evaluation (the end of April 2012):
  1. representatives of Scientific Institutes (e.g. CERN, GSI) and companies (e.g. NI)
  2. members of WR Collaboration and external experts
  3. the responsibility of the group is to perform the further actions
2. Each potential path for WR standardization needs to be identified, studied and evaluated
3. The most suitable path (in terms of costs, efforts, time) decided (the end of 2012)
Standardization of White Rabbit within P1588
1. The standardization effort started (February 2013)
2. An official standardization of White Rabbit will mark the end of the project

Project's timeline

	Task	* End date *
1.	Establishment of WR Standardization Group	end of April 2012
2.	Potential standardization path evaluation	end of September 2012
3.	Decision of standardization path choice	end of 2012
4.	Start of standardization efforts	February 2013
5.	First face-to-face IEEE1588 Study Group meeting, Washington	April 2013
6.	Project Authorization Request (PAR) submitted	May 2013
7.	Project Authorization Request (PAR) approved	June 2013
8.	P1588 Working Group formalized	August 2013
9.	High Accuracy Enhancements sub-committee created	August 2013
10.	P1588 Plenary meeting and ISPCS, Lemgo	September 2013
11.	P1588 Plenary meeting organized at CERN	April 2014
12.	P1588 Plenary meeting and ISPCS, Austin	September 2014
13.	P1588 Plenary meeting, San Francisco	January 2015
14.	P1588 Plenary meeting, Stockholm	May 2015
15.	P1588 Plenary meeting, Knoxville	August 2015
16.	P1588 Plenary meeting, Paso Robles	January 2016
17.	Standardization progress reported at WR Workshop (see)	March 2016
18.	P1588 Plenary meeting, Paris	April 2016
19.	P1588 Plenary meeting, Portsmouth	October 2016
20.	P1588 Plenary meeting, Austin	January 2017
21.	P1588 Internal Working Group Ballot 1	Jan to Oct 2017
22.	P1588 Plenary meeting, Kista	November 2017
23.	P1588 Internal Working Group Ballot 2	Oct 2017 to Feb 2018
24.	P1588 Internal Working Group Ballot 3	Feb to June 2018
25.	Sponsor Ballot Pre-check	Feb to Jun 2018
26.	P1588 Sponsor Ballot 1	Jun to July 2018
27.	The 2018 edition of ISPCS conference was hosted at CERN to celebrate near-completion of the new IEEE1588 revision	Sept/Oct 2018
28.	Standardization progress reported at WR Workshop (see)	Oct 2018
29.	P1588 Sponsor Ballot 1 re-circulation 1	Started in May 2019
30.	P1588 Sponsor Ballot 1 re-circulation 2	Started in August 2019
31.	P1588 Sponsor Ballot passed - Draft submitted to IEEE RevCom for approval	September 2019
32.	IEEE RevCom recommended the revised P1588 draft for approval to IEEE SASB (look for P1588)	6 November 2019
33.	IEEE SA Standards Board (SASB) approved the revised P1588 draft (see the announcement)	7 November 2019
--.	Publication of the new revision of IEEE1588 with High Accuracy Option/Profile	2020

Maciej Lipinski - 13 November 2019

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