The Y.1731 recommendation covers the following performance parameters, which are based on Metro Ethernet Forum (MEF) 10:
frame delay — specified as one-way or round-trip delay for a frame, where frame delay is defined as the time elapsed since the start of transmission of the first bit of the frame by a source node until the reception of the frame by the destination node or the same source node
frame delay variation — a measure of the variations in the frame delay between a pair of service frames, where the service frames belong to the same CoS instance on a point-to-point Ethernet connection
The performance parameters listed above are applicable to Ethernet services frames. Services frames are those frames that conform to an agreed-upon level of bandwidth profile conformance and are associated with a particular CoS identifier. Services frames are admitted at the ingress Ethernet flow point of a point-to-point Ethernet connection and should be delivered to the egress Ethernet flow point.
The 7705 SAR supports one-way and two-way Ethernet Delay Measurement (ETH-DM) tests (section 8.2 of the Y.1731 standard). The tests are run using the oam>eth-cfm>one-way-delay-test and oam>eth-cfm>two-way-delay-test commands. Ethernet Delay Variation (ETH-DV) tests are run concurrently with the one-way and two-way ETH-DM tests.
For ETH-DM, the accuracy of the measurement is in the microseconds range.