Network Synchronization
Page 164 7210 SAS M, X Basic System Configuration Guide
The Table 17 shows the selection followed for two reference in both revertive and non-revertive 
modes:
Table 17: 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