The reason why APS switch happened. When the working connection on one end fails, its other end is told to do an APS switch. The following options in the increasing order of priority indicate what type of switch request it is. optApsRevertive : Switch back to working connection after the Wait-to-Restore interval is over, and failures are cleared. It is the lowest priority. optApsManual : Manual switch causes APS switch unless a request of equal or higher priority is in effect. optApsSignalFailureHigh : switch occured due to SD failure. optApsForceSwitch : Forced switch forces hardware to switch the active connection even if the other connection (could be working connection or protection connection) is in alarm. optApsLockOut : This is the highest priority switch. This will override all other requests. optApsLockOut : indicates that the last switchover to the working occurred because of protection lockout.