IEEE 1588 Implementation on a ColdFire Processor, Rev. 0
IEEE 1588 Basic Overview
Freescale Semiconductor2
2 IEEE 1588 Basic Overview
The IEEE 1588 standard is known as Precision Clock Synchronization Protocol for Networked
Measurement Control Systems, or PTP for short. The IEEE 1588 PTP allows clocks distributed across an
Ethernet network to be accurately synchronized using a process where the distributed nodes exchange
timestamped messages.
The technology behind the standard is originally developed by Agilent and used for distributed measuring
and control tasks. The challenge is to synchronize networked measuring devices with each other in terms
of time, therefore able to record measured values providing them with a precise system timestamp. Based
on this timestamp, the measured values can then be correlated with each other.
Typical applications of the IEEE 1588 time synchronization include:
• Time-sensitive telecommunication services that require precision time synchronization between
communicating nodes
• Industrial network switches that synchronize sensors and actuators over a single wire distributed
control network to control an automated assembly process
• Powerline networks that synchronize across large-scale distributed power grid switches to enable
smooth transfer of power
• Test/measurement devices that must maintain accurate time synchronization with the device under
test in many different operating environments
These applications require precise clock synchronization between devices with accuracy in the
sub-microsecond range. It is a remarkable feature of the IEEE 1588 that this synchronization precision is
achieved via the regular Ethernet connectivity using standard Ethernet frames. This must be assumed to
be non real-time capable.
This solution allows nearly any device of any performance to participate in high precision synchronized
networks that are simple to operate and configure.
Other key benefits of the IEEE 1588 protocol include:
• IEEE 1588 protocol enables rapid convergence (less than a minute) to sub-microsecond time
synchronization between heterogeneous distributed devices with different clocks, resolution, and
stability.
• The IEEE 1588 network configures and segments itself automatically. Each node uses the best
master clock algorithm (BMC) to determine the best clock in the segment. Every PTP node stores
its features within a specified dataset. These features are transmitted to other nodes within its sync
telegrams. Based on this, other nodes are able to synchronize their datasets with the features of the
actual master and can adjust their clocks. Due to the cyclic running of the BMC, nodes can also be
connected or removed during propagation time (hot swapping).
• Simple configuration and operation with low compute resource and network bandwidth
consumption
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