Central Synchronization Subsystem - Nokia 7210 Configuration Manual

7210 SAS-M, T, R6, R12, Mxp, Sx, S Basic System
Configuration Guide
Each synchronization capable port can be independently configured to transmit data
using the node reference timing. In addition, some TDM channels can use adaptive
timing or loop timing.
Transmission of a reference clock through a chain of Ethernet equipment requires
that all equipment supports Synchronous Ethernet. A single piece of equipment that
is not capable of performing Synchronous Ethernet breaks the chain. Ethernet
frames will still get through but downstream devices should not use the recovered
line timing because it will not be traceable to an acceptable stratum source.

6.5.1 Central Synchronization Subsystem

The timing subsystem has a central clock located on the CPM. The timing subsystem
performs several functions of the network element clock as defined by Telcordia
(GR-1244-CORE) and ITU-T G.781 standards.
The central clock uses the available timing inputs to train its local oscillator. The
number of timing inputs available to train the local oscillator varies per platform. The
priority order of these references must be specified. This is a simple ordered list of
inputs: (ref1, ref2, BITS (if available)).
The CPM clock output can drive the clocking for all line cards in the system. The
routers support selection of the node reference using Quality Level (QL) indications.
The recovered clock can derive its timing from one of the references available on that
platform.
The recovered clock can derive the timing from any of the following references (also
shown in
Figure 24
platforms, and
3HE 17358 AAAB TQZZA
Figure 24):
• synchronous Ethernet ports
On the 7210 SAS-M (includes all variants), 7210 SAS-T (includes all variants),
7210 SAS-R6, 7210 SAS-R12, 7210 SAS-Sx 1/10GE (all variants),
7210 SAS-S 1/10GE (all variants), and 7210 SAS-Sx 10/100GE
• 1588v2/PTP slave port
On the 7210 SAS-M (includes all variants), 7210 SAS-T (includes all variants),
7210 SAS-R6, 7210 SAS-R12, 7210 SAS-Sx 1/10GE(all variants)
shows a logical model of synchronization reference selection for the
Table 31
Use subject to Terms available at: www.nokia.com
provides a list of supported interfaces for each platform.
© 2021 Nokia.
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