Information About Frequency Synchronization - Cisco ASR 9000 Series User Configuration Manual

Configuring Frequency Synchronization
Frequency Synchronization is used to distribute precision frequency around a network. This module describes
the tasks required to configure frequency synchronization on the Cisco IOS XR software.
For more information about frequency synchronization on the Cisco IOS XR software and complete
descriptions of the commands listed in this module, see Additional References. To locate documentation for
other commands that might appear in the course of running a configuration task, search online in
Cisco ASR 9000 Series Aggregation Services Router Commands Master List.
Table 24: Feature History for Implementing Frequency Synchronization on Cisco IOS XR Software
Release
Release 3.9.0
Release 5.3.0
This module contains the following topics:
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Information About Frequency Synchronization

Frequency or timing synchronization is the ability to distribute precision frequency around a network. In this
context, timing refers to precision frequency, not an accurate time of day. Precision frequency is required in
next generation networks for applications such as circuit emulation. To achieve compliance to ITU specifications
for TDM, differential method circuit emulation must be used, which requires a known, common precision
frequency reference at each end of the emulated circuit.
The incumbent example of frequency synchronization is provided by SDH and SONET equipment. This is
used in conjunction with an external timing technology (such as Cesium oscillators or GPS) to provide
synchronization of precision timing across the network. As, increasingly, SDH and SONET equipment is
replaced by Ethernet equipment this frequency synchronization ability is required over Ethernet ports.
Modification
This feature was introduced.
Support introduced for nV Cluster Clocking.
Information About Frequency Synchronization, page 191
Configuring Frequency Synchronization, page 193
Cisco ASR 9000 Series Aggregation Services Router System Management Configuration Guide, Release 5.1.x
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