Per its description, this CienaGlobalState object controls the cienaCesRstpPvstBpduReceivedNotification trap, which fires when the switch detects Cisco PVST+ BPDUs on a port running standard RSTP. Because PVST and RSTP/MSTP are not directly interoperable, receiving PVST BPDUs on an RSTP port usually signals a misconfigured or mismatched neighbor switch at the other end of that link. An engineer connecting a new access switch into an existing RSTP core would want this trap enabled to immediately catch a vendor-interop mismatch instead of discovering it later as an unexplained blocked port.