A method and system for performing synthetic loss measurements (SLM) includes methods for single-ended and dual-ended synthetic loss measurements. The methods include maintaining a session number indicative of a physical network component at each maintenance point used to perform synthetic loss measurements. The session numbers are maintained according to a novel protocol and are used to detect a change in the network component, such as resulting from a protection switch event. The session numbers enable the synthetic loss measurements to continue irrespective of changes in the values for the session numbers and to remove errors when computing frame loss that may arise when physical network components change. The disclosed methods and systems may be used when a link aggregation group exists between a local maintenance point and a remote maintenance point.