Propagation Delay Measurement Using A Single-TimeSync Frame in Bridged Local Area Networks

Time and frequency alignment is critical for ensuring QoS for applications such as voice, real-time video, wireless hand-off, and data over a converged access medium. To satisfy the accuracy of time synchronization, propagation delay measurement is required between time-sensitive devices. There is existing network technology for time synchronization, such as network time protocol (NTP), IEEE 1588 precision time protocol (PTP), and IEEE 802.1AS. NTP, however, is not suitable for synchronization in time-sensitive applications. IEEE 1588 PTP and IEEE 802.1AS have problems where there are too many messages in LAN. We propose a single frame format and a method of propagation delay measurement using a single frame in bridged LANs. The experiment results show that the proposed method reduces time variation from NTP and control messages about 47% from IEEE 802.1AS.