Patent ID: 8126102
Filing Date: 2012-02-28
Classification: H04J

Abstract:
1. A communication apparatus that selects any one clock from among clocks supplied through a plurality of paths from supplying apparatuses of a master clock and that synchronizes a clock of the communication apparatus with the clock selected, the communication apparatus comprising: a receiving unit that receives information indicating a relay count on a path from a supplying apparatus to a first communication apparatus connected to the communication apparatus on a side of the supplying apparatus, the information being received for each of the paths from a plurality of the first communication apparatuses; a synchronizing unit that, based on the information received by the receiving unit, synchronizes the clock of the communication apparatus with a clock of a first communication apparatus having the relay count of a small number among the first communication apparatuses; and a transmitting unit that transmits, for each of the paths, information indicating a relay count from a supplying apparatus to the communication apparatus, the information being transmitted respectively to second communication apparatuses, wherein: the transmitting unit transmits, as the information indicating the relay count from the supplying apparatus to the communication apparatus, information formed by adding a relay count for the communication apparatus to the information that indicates the relay count and is received by the receiving unit; the receiving unit receives, for each of the paths, information indicating whether a branching communication apparatus to which clocks are supplied through three or more paths is included in a path from a supplying apparatus to a first communication apparatus, the information being received respectively from each of the first communication apparatuses, the transmitting unit transmits, for each of the paths, information indicating whether a branching communication apparatus is included in the path from the supplying apparatus to the communication apparatus, the information being transmitted respectively to the second communication apparatuses, and the synchronizing unit synchronizes the clock of the communication apparatus with the clock of a first communication apparatus on a path for which the information received by the receiving unit indicates that a branching communication apparatus is not included.