A complex network processing information or physical flows is usually
characterized by a number of macroscopic quantities such as the diameter and
the betweenness centrality. An issue of significant theoretical and practical
interest is how such a network responds to sudden changes caused by attacks or
disturbances. By introducing a model to address this issue, we find that, for a
finite-capacity network, perturbations can cause the network to
\emph{oscillate} persistently in the sense that the characterizing quantities
vary periodically or randomly with time. We provide a theoretical estimate of
the critical capacity-parameter value for the onset of the network oscillation.
The finding is expected to have broad implications as it suggests that complex
networks may be structurally highly dynamic.Comment: 4 pages, 4 figures. submitte