A method (60; 70) for processing data packets allows the same hardware that is used in a traffic-forwarding path to add timestamps to the data, which allow accurate measurements to be taken. By adding this function in the forwarding equipment itself, the measurements can be taken in a true operational network, i.e., under actual usage conditions. Moreover, if multiple systems in the traffic path support this functionality, the value of the measurements is enhanced to enable end-to-end path guarantees. One exemplary embodiment (10) of the present invention uses synchronized clocks to provide timestamps for use in performance monitoring within an operational system. Synchronized clock signals can be used to accurately time stamp incoming and outgoing packets to provide performance measurement of traffic through the system under actual operating conditions.