Patent ID: 8873588

Claim:
A method of performing timing related processing, the method comprising: synchronizing a first local clock of a first Ethernet line card and a second local clock of a second Ethernet line card, the first and second Ethernet line cards separated by a non-precision time protocol network, the first Ethernet line card being part of a first node and the second Ethernet line card being part of a second node of the non-precision time protocol network, the first Ethernet line card and the second Ethernet line card each being connected to a precision time protocol network such that the first Ethernet line card sends and receives packets via a first communications port to and from the precision time protocol network and the second Ethernet line card sends and receives packets via a second communications port to and from the precision time protocol network; determining a time of arrival of a packet at the first Ethernet line card; inserting an indication of the time of arrival of the packet at the first Ethernet line card into a reserved field of the packet; transmitting the packet over the non-precision time protocol network to the second Ethernet line card; determining a time of departure of the packet from the second Ethernet line card; and adding a value equal to the time of departure of the packet from the second Ethernet line card minus the time of arrival of the packet at the first Ethernet line card to a value of a correction field of the packet.