Patent ID: 8160053

Claim:
A clock tracing method in a network, comprising: determining a shortest path to a best clock source network element according to stored network topology information and clock source network element information, including: determining a shortest path to each clock source network element according to the stored network topology information and the clock source network element information, selecting the best clock source network element among all clock source network elements, and determining the shortest path to the best clock source network element; or selecting the best clock source network element among all clock source network elements, and determining the shortest path to the best clock source network element according to the stored network topology information and the clock source network element information; using the shortest path to the best source network element as a clock tracing path if the shortest path to the best source network element is different from an old clock tracing path and a traceable message is received, using the clock tracing path for tracing clocks; obtaining a clock tracing tree rooted at the best source network element through a link management protocol and/or a routing protocol; determining a neighboring upstream network element and a neighboring downstream network element according to the clock tracing tree; and sending, by the neighboring upstream network element, the traceable message to the neighboring downstream network element along the clock tracing tree if the neighboring upstream network element finishes clock tracing.