Measuring performance of a network using mirrored probe packets

Functionality is described herein for measuring the performance of a network. The functionality operates by generating a probe packet and injecting the probe packet into the network. The probe packet is configured, using one or more layers of encapsulation, to target a particular network component of interest in the network, or to target a particular collection of network components in the network. A switch to which the probe packet is addressed operates by: (a) generating mirrored information that is associated with the probe packet; (b) decapsulating the probe packet (with respect to its outermost encapsulation) to produce a new probe packet; and (c) passing the new probe packet to a downstream network component, in accordance with a destination address associated with the new probe packet. The functionality uses the mirrored information that has been collected in the above manner to detect various anomalies in the network.