Patent ID: 8233432

Claim:
A method of controlling distribution of data between entities in a wired network comprising: estimating a distance between a first entity and a second entity including determining a propagation delay for a signal transmission between the first entity and the second entity across the wired network and calculating a distance based on the propagation delay, wherein the determination of the propagation delay includes: determining a relationship between a clock in the first entity and a clock in the second entity, wherein establishing the relationship between the clock of the first entity and the clock of the second entity includes synchronizing the clocks to a time server; transmitting a data packet from the first entity to the second entity over the wired network, the packet containing a transmission time; receiving the data packet at each of one or more intermediate nodes in a path for the data packet between the first entity and the second entity, determining and inserting a processing delay for each of the one or more intermediate node in the data packet, and retransmitting the data packet from each of the one or more intermediate nodes; receiving the packet at the second entity at a receive time; returning the packet from the second entity at a second transmission time; receiving the returned packet at each of one or more intermediate nodes in a path for the return packet between the second entity and the first entity, determining and inserting a processing delay for each of the one or more intermediates node in the returned packet, and retransmitting the returned packet from each of the one or more intermediate nodes; receiving the returned packet at the first entity at a second receive time; determining the propagation delay using the transmission times and the receive times for the first and second entities and the processing delays for the intermediate nodes; and distributing the data between the first entity and the second entity only if the estimated distance between the first entity and the second entity is within a distance threshold for the data.