Alcatel Lucent

Ian Leighton

Peter Roberts

Kin Yee Wong

Kin-Yee Wong

Matthew Simone

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.

Faster synchronization time and better master selection based on dynamic accuracy information in a network of IEEE 1588 clocks

An intermediate clock, either a boundary or a transparent clock, may have to adjust its local clock to match that of a grandmaster clock. If such adjustment is frequent or large, then the intermediate clock may not have much confidence in the reliability of the timing information it passes to a downstream clock in an IEEE 1588 Announce message even if the quality of its local clock is high. The intermediate clock determines a measure of the reliability of its timing information. The intermediate clock inserts an indication of the reliability of the timing information in a transmitted IEEE 1588 Announce message. The intermediate clock may consider an indication of reliability found in an Announce message it receives when inserting an indication of the reliability of timing information into an Announce message which it transmits.

Distribution of dynamic accuracy information in a network of IEEE 1588 clocks

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.

Various exemplary embodiments relate to a method performed by a first network element, the method including: receiving first user inputs for mapping IEEE 1588 clock class into ITU-T G.781 quality levels; producing a first table that maps clock class to quality level; providing the first table to a second network element; receiving second user inputs for mapping ITU-T G.781 quality level into IEEE 1588 clock class; producing a second table that maps quality level to clock class; and providing the second table to the second network element.

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Ottawa, Canada

Ian Leighton