FASTER SYNCHRONIZATION TIME AND BETTER MASTER SELECTION BASED ON DYNAMIC ACCURACY INFORMATION IN A NETWORK OF IEEE 1588 CLOCKS

摘要

A method and system are provided for synchronizing local clocks more quickly in a telecommunication network using IEEE 1588. A network element that receives timing signals from one or more possible parent clocks considers a measure of the reliability of the timing signals contained in Announce messages from the parent clock or clocks. The clock uses this reliability information in selecting one of the possible parent clock or clocks to use as the actual parent clock. Once the selection is made, the clock adjusts the filtering characteristics applied to timing signals received from the selected parent clock. The adjustments reflect how confident the parent clock is as to how stable the timing information, it provides has become. If the indication of reliability contained in Announce messages received from the parent clock indicates that the timing information is not very reliable, then a high filter bandwidth is used in filtering the timing signals. If the indication of reliability contained in Announce messages indicates that the timing information is reliable, such as by crossing a threshold, then the clock shifts to a normal low bandwidth filtering. By using reliability information in the Announce messages, clocks can better make selections as to which parent clock to use, and can use the reliability information to more quickly synchronize themselves with a grandmaster clock.