PTP Version 2
Requirements from new application areas and new ideas how PTP can further be improved have triggered standard revision activities. On March 20, 2005 the Standards Board of the IEEE Standards Association approved the Project Authorization Request. It authorizes the P1588 Working Group to extend the original IEEE 1588 standard.
Some important enhancements, among others, are:
- enablers for increased accuracy (higher timestamp resolution, shorter sync intervals, correction field)
- new clock types: the peer-to-peer and the end-to-end transparent clocks are designed to improve synchronization in linear topology (i.e. daisy chained clocks) by avoiding cascaded servos
- rapid reconfiguration after network topology changes
- fault tolerance
- unicast operation
- new mappings (e.g. PTP directly on Ethernet MAC layer, without IP/UDP)
- flexible extension mechanism
The Institute of Embedded Systems (InES) is committed to PTPv2 and has, together with Hirschmann Automation and Control, developed a pre-standard prototype implementation of an end-to-end transparent clock (PDF 1,8 MB). The prototype has been presented at the 2006 Conference on IEEE 1588 in Gaithersburg.
The diagram on the right hand side of this page shows a slave’s deviation from master. The slave is synchronized across 7 heavily loaded switches (traffic on all ports is 90% of theoretical capacity in both directions). During a test run of 5 hours the master/slave deviation varied with σ = 33,9ns.