White Rabbit Protocol (WRPTP)
White Rabbit* (WR) is a protocol developed to synchronize nodes in a packet-based network with sub-ns accuracy. The protocol results from the combination of IEEE1588-2008 (Precision Time Protocol, PTP) with two further requirements: precise knowledge of the link delay and clock syntonization over the physical layer with Synchronous Ethernet (SyncE).
White Rabbit evolved into an extension of Precision Time Protocol (PTP), therefore it is referred to as WRPTP. WRPTP is fully compatible with PTP and is currently defined as a PTP Profile.
White Rabbit Specification (WR Spec)
White Rabbit Protocol is defined in the White Rabbit Specification (WR Spec) which describes:
- hardware requirements which need to be fulfilled to implement WRPTP
- protocol requirements which need to be fulfilled to be WRPTP-compatible
The latest version of the WR Spec can be found here. In order to show how the WR Spec evolved, older versions of the WR Spec can be found here while short information regarding different versions (i.e. feedback, comments, diffs) is provided here. The sources (Latex) of the WR Spec document are available in the project's repository (here).
White Rabbit Standardization
Standardizing White Rabbit is unquestionably beneficial to the project
and is expected to bring substantial boost to the number of WR's
applications.
Advantages of standardization:
- easier co-operation with companies
- increase of stability, viability and credibility of the White Rabbit solution (favored by potential users)
- feedback of field's expert which enables to polish the solution and make it more mature
Standardization is a considerably long process which can be approached in various ways and from various directions. So far, a few potential paths (see presentation) for WR's standardization have been identified. These include:
-
Standardization at 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 Institute of Electrical and Electronics
Engineers (IEEE)
- as a PTP Profile
- within revision 3 of PTP
- Standard within other standardization body/consortium
Goal of this project
The ultimate goal of this project is to standardize White Rabbit Protocol.
Project's plan
- _White Rabbit Standardization Group_ is to be
established (by the end of April 2012):
- representatives of Scientific Institutes (e.g. CERN, GSI) and companies (e.g. NI)
- members of WR Collaboration and external experts
- the responsibility of the group is to perform the further actions
- Each potential path for WR standardization needs to be identified, studied and evaluated
- The most suitable path (in terms of costs, efforts, time) should be decided (by the end of 2012)
- The standardization effort should be started
- An official White Rabbit standard will mark the end of the project