Method for synchronizing distributed clocks by the precision time protocol, in a telecommunication network

A method for synchronizing distributed clocks by the Precision Time Protocol, in a telecommunication network, comprising the steps of:

• sending a Sync message from one clock to another via a plurality of network nodes, a first of these nodes nodes comprising a first peer-to-peer transparent clock and a second of these nodes comprising a second peer-to peer transparent clock,
• estimating the path delay of the transmission path travelled by the synchronization message from the first to the second peer-to-peer transparent clocks, by:
• sending a Pdelay_Req message from the second peer-to-peer transparent clock to the first peer-to-peer transparent clock,
• and sending a Pdelay_Resp message from the first peer-to-peer transparent clock to the second peer-to-peer transparent clock,
• and then taking this path delay into account for updating the time information carried by a synchronization message, in the second peer-to-peer transparent clock;
• where in, for estimating said path delay it comprises the steps of:
• using a tool, available in the transport protocol, for creating in network node associated to the first peer-to-peer transparent clock, a list of the network addresses of the network interfaces transversed by the synchronization message along its transmission path between the first and the second peer-to-peer transparent clocks;
• ordering the first list into the order in which the network interlaces have been traversed by the Sync message;
• creating a second list by reversing the order of the first list;
• communicating the second list to the second peer-to-peer transparent clock;
• and using the mechanism available in the transport protocol, in network nodes associated respectively to the first and the second peer-to-peer transparent clocks to constrain the respective paths of Pdelay_Req and Pdelay_Resp messages so that their respective paths map to the second and first ordered lists of traversed interfaces.