Cluster TDEV a new performance metric for timing over packet networks

One of the main topics on the ITU-T study group 15 (SG15/Q13) agenda is defining new network performance limits for recovered timing information across packet networks. The metrics shall apply to the network packet delay variation (PDV) sequence and help in projecting the required system bandwidth given a specific performance envelope. Current ITU-T TDEV-based metrics are based on processing percentiles of the input PDV sequence. In this paper we introduce a new metric, which is primarily based on a time domain packet clustering approach. The new metric provides more flexibility and improves the prediction of clock recovery performance through operation over different bands of the input network delay sequence. The new metric also provides the designer with the option of using network-specific cluster anchor points. This improves the chances of identifying the most suitable network delay bands for a timing over packet clock recovery system that meets the performance envelope.