An endpoint for determining a frame loss ratio is provided. The endpoint includes a processor and a memory coupled with the processor. The memory stores instructions that are executable to generate a number of synthetic frames, and insert the number of synthetic frames into a stream of data frames, the synthetic frames being transmitted to a responder endpoint address designated in the synthetic frames. The memory may also store instructions that are executable to determine a number of lost synthetic frames; and calculate a synthetic frame loss ratio as a function of the number of lost synthetic frames and the number of synthetic frames inserted into the stream of data frames.