A notion of disturbance propagation stability is defined for dynamical
network processes, in terms of decrescence of an input-output energy metric
along cutsets away from the disturbance source. A characterization of the
disturbance propagation notion is developed for a canonical model for
synchronization of linearly-coupled homogeneous subsystems. Specifically,
propagation stability is equivalenced with the frequency response of a certain
local closed-loop model, which is defined from the subsystem model and local
network connections, being sub-unity gain. For the case where the subsystem is
single-input single-output (SISO), a further simplification in terms of the
subsystem's open loop Nyquist plot is obtained. An extension of the disturbance
propagation stability concept toward imperviousness of subnetworks to
disturbances is briefly developed, and an example focused on networks with
planar subsystems is considered