System Management
7210 SAS D, E, K OS Basic System Configuration Guide Page 193
On 7210 SAS-D ETR and 7210 SAS-K, , the recovered clock is able to derive the timing from any
of the following references (also shown in the Figure 19 below):
• Synchronous Ethernet ports
• 1588v2/PTP slave port
Figure 19: Synchronisation Reference selection on 7210 SAS-D ETR
When QL selection mode is disabled, then the reversion setting controls when the central clock
can re-select a previously failed reference.
The Table 20 shows the selection followed for two references in both revertive and non-revertive
modes:
Table 20: 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
OK Failed A A
OK OK A A
Failed Failed holdover holdover
OK Failed A A
Failed Failed holdover holdover
Failed OK B B
Failed Failed holdover holdover
OK OK A or B A