This selects whether this APS group automatically switches traffic back to the working line once the fault that caused a protection switch has cleared (revertive) or instead leaves traffic on the protection line until another explicit switch request comes in (nonrevertive) -- and critically, this must be set to revertive if cApsConfigMode is oneToN, since that shared-protection-channel architecture depends on channels reverting to free up the shared backup for other working channels. Choosing nonrevertive on a 1+1 group means a transient fault that self-clears won't cause a second, potentially disruptive switch back, at the cost of continuing to use the protection path even after the original problem is gone. For example, a oneToN group must use revertive so that once a temporarily-failed working channel recovers, it releases the shared protection channel back to being available for whichever other working channel might fail next.