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.
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
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
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:
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
feedback of experts that enables to polish the solution and make it
Standardization is a considerably long process that can be approached in
various ways and from various directions. Potential paths (see
for WR's standardization had been identified. These included:
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
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.