PTP is used to implement high-precision time and frequency synchronization between devices on an Ethernet network. In this document, PTP includes 1588v2 and G.8275.1.
IEEE 1588 provides high-precision time synchronization. Two versions exist: 1588v1 and 1588v2. IEEE 1588v1 provides sub-millisecond precision time synchronization. This version has been replaced by IEEE 1588v2, which provides sub-microsecond precision time synchronization.
Similar to IEEE 1588, G.8275.1 is designed to meet requirements for precise time synchronization between devices across an entire network. However, unlike IEEE 1588, G.8275.1 can be widely used in a variety of domains, such as power, measurement and control, military, and telecommunications systems. G.8275.1 is a telecommunications-specific protocol defined by ITU-T.
On wireless networks, clock synchronization is critical in enabling successful communication between the mobile bearer network and base stations. A number of methods, such as the global positioning system (GPS), Network Time Protocol (NTP), and synchronous Ethernet, can be used to implement time and frequency synchronization. However, GPS requires antennas to be deployed at each base station, leading to high deployment and maintenance costs. NTP provides only sub-second precision time synchronization, which is unable to meet precise synchronization requirements. Synchronous Ethernet supports only high-precision frequency synchronization but not time synchronization.
PTP addresses the limitations found in the preceding methods. It is inexpensive to deploy and maintain. 1588v2 and G.8275.1 can provide sub-microsecond precision time synchronization and offers increased security because it operates independent of the GPS.