Alcatel-Lucent 7210 SAS M - Table 19: Revertive, Non-Revertive Timing Reference Switching Operation; Figure 15: Synchronisation Reference Selection on 7210 SAS-M, 7210 SAS-X and 7210 SAS-D ETR

System Management
7210 SAS M, T, X, R6 Basic System Configuration Guide Page 217
platform. See Figure 15 below for a description of synchronization reference selection for the
7210 platforms.
On 7210 SAS-D ETR, 7210 SAS-M (includes all variants), 7210 SAS-T (includes all variants),
and 7210 SAS-X and 7210 SAS-R6, the recovered clock is able to derive the timing from any of
the following references (also shown in the Figure 15 below):
• Synchronous Ethernet ports
• 1588v2/PTP slave port
Figure 15: Synchronisation Reference selection on 7210 SAS-M, 7210 SAS-X and 7210 SAS-D ETR
On 7210 SAS-M (includes all variants), when the CES MDA is in use, in addition to the above
references, the recovered clock derives the timing from any of the following references:
• T1/E1 CES channel (not available for node reference)
• T1/E1 port (for loop-timing; not available for node reference)
When QL selection mode is disabled, then the reversion setting controls when the central clock
can re-select a previously failed reference.
The Table 19 shows the selection followed for two references in both revertive and non-revertive
modes:
Table 19: Revertive, non-Revertive Timing Reference Switching Operation
Status of
Reference A
Status of
Reference B
Active Reference
Non-revertive Case
Active Reference
Revertive Case
OK OK A A
Failed OK B B
OK OK B A