Covert Channel for One-Way Delay Measurements

We propose a novel, passive, nonintrusive method to measure the one-way delay of all the packets flowing between customer sites connected by a provider backbone. Our approach does not sample traffic and requires the injection of a negligible amount of control packets, possibly none. This is obtained by deploying a Measurement Agent in each customer site and exploiting a covert channel to carry information about each packet that transits between the Measurement Agents. Further, we address the theoretical problems of encoding measurement information into the very limited amount of bits made available by the covert channel, obtaining one-way delay measurements with predictable accuracy. Finally, we experimentally validate the applicability of our approach.