Optical Transport Network Delay Measurement

In one embodiment, a one-way delay is measured between optical devices in an optical transport network based on roundtrip times of request and corresponding response frames. A first optical device sends a sequence of delay measurement request frames to a second optical device, which varies a local delay before responding to a request frame, thus causing a slippage in the sequence of reply frames received by the first device. The point at which the request frames are received in relation to the stream of frames sent by the optical device can be identified based on the frame slippage. Therefore, the delay measurement can be adjusted by a corresponding offset to the beginning of a frame in order to increase the accuracy of the one-way delay measurement.