Network Synchronization - Alcatel-Lucent 7450 ESS-12 Configuration Manual

Network Synchronization

This section describes network synchronization capabilities available on SR OS platforms. These
capabilities involve multiple approaches to network timing; namely SDH/SONET, Synchronous
Ethernet, and Adaptive clocking and a Precision Time Protocol (PTP) IEEE 1588v2. These
features address barriers to entry by:
•
•
Network synchronization is commonly distributed in a hierarchical master-slave topology at the
physical layer as shown in
Stratum 1
Gateway
Class 1 or 2 CO
Stratum 2
Class 2 or 3
Central Office
Stratum 3
Class 4 or 5
Toll/End Office
Stratum 4
Customer
Prem
Figure 8: Conventional Network Timing Architecture (North American Nomenclature)
The architecture shown in
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Providing synchronization quality required by the mobile space; such as radio operations
and circuit emulation services (CES) transport.
Augmenting and potentially replacing the existing (SONET/SDH) timing infrastructure
and delivering high quality network timing for time sensitive applications in the wireline
space.
Figure
ST 2
ST 3
ST 4 ST 4
Primary Reference
Secondary Reference
Figure 9
Limits the need for high quality clocks at each network element and only requires that
they reliably replicate input to remain traceable to its reference.
Uses reliable physical media to provide transport of the timing signal; it doesn't consume
any bandwidth and requires limited additional processing.
9.
Primary Reference Clock
ST 3 ST 3
ST 4 ST 4
provides the following benefits:
7450 ESS OS Basic System Configuration Guide
ST 2
ST 3 ST 3
ST 4 ST 4 ST 4