Precise timing is increasingly used in a wide range of applications and commercial infrastructures such as mobile communications, networking, the smart grid, the network of Internet of Things IoT , industrial automation and financial technologies Fintech. There is an ever-expanding set of critical infrastructure that is required to provide precise time and frequency for such applications. This requirement is growing and becoming increasingly pervasive in worldwide communication networks and commercial infrastructure. In addition, measurement and automation systems require event synchronization and data correlation especially when multiple devices are involved in the measurement.
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Starting with Junos OS Release This synchronization is achieved through packets that are transmitted and received in a session between a master clock and a slave clock or remote clock client. A boundary clock is both a clock source and a clock client. An ordinary clock is either a clock source or a clock client. However, a grandmaster clock is always a clock source. An ordinary clock on a device is always a clock client. Boundary clock—A boundary clock has multiple network connections and can act as a source master and a destination slave or clock client for synchronization messages.
It synchronizes itself to a best master clock through a slave port and supports synchronization of clients to it on master ports. Boundary clocks can improve the accuracy of clock synchronization by reducing the number of v2-unaware hops between the master and the client. Boundary clocks can also be deployed to deliver better scale because they reduce the number of sessions and the number of packets per second on the master. Ordinary clock—The PTP ordinary clock has a single network connection and can act as a source master or destination slave or clock client for synchronization messages.
On devices, the ordinary clock is a slave, which receives synchronization reference messages from a master, either a grandmaster or a master boundary clock. You cannot configure an ordinary master on a device.
However, a boundary clock can provide time to the ordinary slave. The grandmaster clock is an external device to which the boundary or ordinary clock synchronizes.
You cannot configure a grandmaster clock on a device. However, a boundary clock slave or an ordinary clock slave can receive time from a grandmaster clock. Clock source—A clock source is the PTP master clock to which the slave synchronizes. The clock source is included in the configuration of the slave clock.
The clock client is included in the configuration of the master clock. Unicast mode IPv4 on Gigabit Ethernet interfaces only —Unicast mode is a user-to-user protocol used to send a datagram to a single recipient. Unicast mode is used for transporting PTP messages.
You can configure an aggregated Ethernet interface and its configured IP address for PTP streams acting as slaves or masters. IP hashing determines which physical link to use for the PTP traffic flows. Both IPv4 unicast and IPv6 unicast transport are supported. You can configure a loopback interface there is only one loopback interface, and it is lo0.
The IP address configured on lo0. You can configure multiple IP addresses on lo0. Although, the loopback interface is the same for both masters and slaves, the IP addresses must be unique.
Configuring Precision Time Protocol Clocking. Help us improve your experience. Let us know what you think. Do you have time for a two-minute survey?
Maybe Later. The following key PTP features are supported:.
IEEE 1588v2 Precision Timing Protocol (PTP)
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The IEEE 1588 Standard
On a local area network , it achieves clock accuracy in the sub-microsecond range, making it suitable for measurement and control systems. IEEE was published in November and includes backward-compatible improvements to the publication. Several profiles have been defined for applications including telecommunications , electric power distribution and audiovisual. IEEE It is also designed for applications that cannot bear the cost of a GPS receiver at each node, or for which GPS signals are inaccessible. In , IEEE was released as a revised standard; also known as PTP version 2 PTPv2 , it improves accuracy, precision and robustness but is not backward compatible with the original version. The IEEE standards describe a hierarchical master-slave architecture for clock distribution.
Precision Time Protocol