Juniper ACX2000 Configuration Guide

of an accurate clock over a packet-switched network. This synchronization is achieved
through packets that are transmitted and received in a session between a master clock
(commonly called the master) and a slave clock (also known as the slave in PTP
terminology). PTP synchronizes both frequency and phase including time of day. The
accuracy of clock synchronization depends on factors such as packet delay variation,
quality of oscillator used, network asymmetry, and so on.
Synchronous Ethernet and PTP provide frequency and phase synchronization; however,
the accuracy in the order of nanoseconds is difficult to achieve through PTP or
Synchronous Ethernet and they do not support a large number of network hops. Hybrid
mode resolves these issues by extending the number of network hops and also provides
clock synchronization accuracy in the order of tens of nanoseconds.
Hybrid mode is configured on the slave. On the slave, you can configure one or more
interfaces as Synchronous Ethernet source interfaces.
NOTE: Router clocks are categorized based on the role of the router in the
network. They are broadly categorized into ordinary clocks and boundary
clocks. The master clock and the slave clock are known as ordinary clocks.
The boundary clock can operate as either a master clock or a slave clock.
In hybrid mode, the following show commands display information regarding the hybrid
status configuration:
•
The show ptp status details command displays the time and phase plane status.
•
The show chassis synchronization extensive command displays the frequency plane
status.
•
The show ptp hybrid status command displays the hybrid (combined status of frequency
and phase plane) status.
•
In hybrid mode, the show ptp hybrid status and show ptp lock-status commands indicate
the lock status as Phase Aligned in the output.
For information about configuring hybrid mode, see Configuring Hybrid Mode and ESMC
Quality Level Mapping. You can use the show ptp hybrid status operational command to
find the current operating mode.
Supporting Platforms
Hybrid mode is supported on the Juniper Networks ACX Series Universal Access Routers.
The combined operation is possible only when the PTP client and the Synchronous
Ethernet source are on the same device and are traceable to the same primary reference
clock (also known as PRC).
When acting as PTP slaves, the ACX Series routers can accept any external Synchronous
Ethernet clock as reference and do not support building-integrated timing supply (BITS)
input as frequency source in hybrid mode of operation. Only Synchronous Ethernet sources
289Copyright © 2017, Juniper Networks, Inc.
Chapter 9: Configuring Timing and Synchronization

Juniper ACX2000 Specifications

General

Brand	Juniper
Model	ACX2000
Category	Network Router
Language	English