  This paper is concerned with the study of scalability in nonlinear
heterogeneous networks affected by communication delays and disturbances. After
formalizing the notion of scalability, we give two sufficient conditions to
assess this property. Our results can be used to study leader-follower and
leaderless networks and also allow to consider the case when the desired
configuration of the system changes over time. We show how our conditions can
be turned into design guidelines to guarantee scalability and illustrate their
effectiveness via numerical examples.
