Time synchronization over Ethernet

Time synchronization standards
The following time synchronization protocols are relevant when time is distributed over Ethernet:
- IEEE1588 D2.2 - 2008, (PTP version 2)
- IEEE1588 - 2002, (PTP version 1)
- NTP, RFC1305
- SNTP, RFC2030

 PTP Grand Master Clock
A PTP Grand Master Clock represents the clock source of a network.  The PTP Grand Master is often based on GPS as external time and the unit sends and receives Ethernet time sync packets with precise transmit and receive time stamps.  OnTime provides a PTP Grand Master that is also a 8 port managed Ethernet switch.  The OnTime PTP Grand Master will act as a switch with PTP Transparent Clock properties if a better PTP Grand Master candidate exist in the network.
PTP Transparent Clock
A PTP Transparent Clock forwards PTP time sync packets to/from the PTP Grand Master clock and the PTP Slave Clocks. The variable switch delay for each PTP time sync event packet is measured and the corresponding follow up packet is updated with this measured delay.  The PTP Transparent Clock of OnTime is also a 8 port managed Ethernet switch.
PTP Slave Clock

 A PTP Slave Clock received PTP time sync packets from the master and updates its local clock so that the clock is synchronized with the grand master clock of the network.  The PTP Slave Clock of OnTime is also a 8 port managed Ethernet switch with PTP Transparent Clock properties.  The PTP Slave Clock contains also non-Ethernet interface for GPS emulation (NMEA and PPS output) or IRIG-B output (copper or fiber).
Products
See T200 for details of the time sync products from OnTime.