This read-only OCNSTMPortType object represents the OCN/STM port type, per its description determining whether the port operates in OC (SONET) or STM (SDH) mode. Administrators read it to confirm which framing standard an optical interface is running, since SONET and SDH use different rate hierarchies and terminology despite similar underlying technology. For example, when documenting an international circuit that crosses between a SONET-based US network and an SDH-based European carrier, an operator would check this object at each end to confirm the framing mode in use.