PTP/IEEE-1588 Slaves
- Home
- >
- PTP/IEEE-1588 Slaves
PTP/IEEE-1588 Slaves
The IEEE-1588 protocol does not define how to implement PTP into a Master or Slave. Two methods have been adopted for PTP over Ethernet: PTP software timestamps and PTP hardware timestamps. The following paragraphs describe these methods.
Slave with Hardware Timestamping
Hardware timestamps with a PTP software daemon provide precise nanosecond timestamp resolution with dedicated hardware typically in a PCIe form factor. The hardware slave solution has many advantages over the software slave such as an improved oscillator, a 1PPS output for measurements compared to the master , and dedicated hardware that is unaffected by the operating system latency. Synchronization of better than 100 nanoseconds is achievable using either a crossover cable or a 1588 Ethernet switch.


Slave with Software Timestamping
Software-only implementations utilize existing computer hardware and a PTP daemon. The slave software solution must compensate for the internal oscillator on the computer motherboard using software timestamping. The local oscillator on the motherboard is typically of poor quality and the software timestamping is affected by the operating system latency. Measuring the software slave to the master is limited to log file statistics, as there is no 1PPS output to compare with the master. Synchronization of 10 microseconds is achievable with a software slave to a master with typical results between 10 to 100 microseconds.