7210 SAS-MXP, R6, R12, S, SX, T BASIC SYSTEM
CONFIGURATION GUIDE RELEASE 22.9.R1
System management
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 22:
Logical model of synchronization reference selection on 7210 SAS):
• synchronous Ethernet ports
On the 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 timeReceiver port
On the 7210 SAS-T (includes all variants), 7210 SAS-R6, 7210 SAS-R12, 7210 SAS-Sx 1/10GE (all
variants)
Figure 22: Logical model of synchronization reference selection on 7210 SAS shows a logical model of
synchronization reference selection for the platforms, and Table 30: Synchronization options for 7210 SAS
platforms provides a list of supported interfaces for each platform.
3HE 18197 AAAB TQZZA
© 2022 Nokia.
Use subject to Terms available at: www.nokia.com/terms/.
258
SPACER TEXT
To Next Page
Loading...