One-way delay measurement allows the operator the ability to check unidirectional delay between MEPs. An ETH-1DM packet is time stamped by the generating MEP and sent to the remote node. The remote node time stamps the packet on receipt and generates the results. The results, available from the receiving MEP, will indicate the delay and jitter. Jitter, or delay variation, is the difference in delay between tests. This means the delay variation on the first test will not be valid. It is important to ensure that the clocks are synchronized on both nodes to ensure the results are accurate. NTP can be used to achieve a level of wall clock synchronization between the nodes.