is used to find the syncreq syncresp pair with the smallest round trip time this measurement is then used to compute the cabs and cdiff values in other words we claim that the best measurement is the one with the smallest rtt many other methods use the mean value note that the method described in fig4 may be implemented somewhat differently for example the sending and receiving of messages can be made concurrently not sequentially as is shown in the figure in that case two processes are created one that is sending syncreq messages regularly and one that is waiting for syncresp messages in that case a timeout need not be made instead a delay between the sending of syncreq messages need to be introduced in fig5 an embodiment of a responder node pre synchronization flowchart is schematically depicted the node waits for a syncreq from the requesting node when such a message is received it creates a syncresp message copies the sequence number and t 1 from the syncreq message records t 2 and t 3 and sends the syncresp message back to the requesting node if the received message is not a syncreq message it is assumed that it is a measurement message which is handled in p 2 b the size of the vectors is equal to the number of measurement messages sent the measurement phase consists of the requesting node periodically sending measurement messages to the responding node the responding node records the timestamps of the time of sending and the time of receiving the messages in two vectors a and b respectively the size of the vectors is equal to the number of measurement messages sent nm the two vectors are later used in p 4 in.