This read-only Integer32 (1..65535) is assigned globally and sequentially to every new trap the device sends, wrapping back to 1 after reaching 65535. An admin cares because it gives each alarm trap a sequence number a management station can use to detect gaps from lost traps. For example, if cmAlmIndex jumps from 100 to 150 in successive traps, the NMS can infer roughly 49 traps were lost in transit and should reconcile via polling.