Performance measurement in a packet-switched communication network

It is disclosed a method for performing a performance measurement on a packet flow transmitted through a packet-switched communication network. In the packet flow, first blocks of packets having a first packet feature and second blocks of packets having a second packet feature are provided by periodically switching a packet feature in the packet flow, so that the first blocks of packets alternate in time with the second blocks of packets. Two or more measurement points on the path of the packet flow provide performance parameters relating to the first and second blocks of packets, and alternately provide their values to a network controller, which the controller uses to perform the performance measurement. The periodic switching of the packet feature and the alternate provision of the performance parameter values are in response to remote commands received from the controller.