  The right performance of a supply chain depends on the pattern of
relationships among firms. Although there is not a general consensus among
researchers yet, many studies point that scale-free topologies, where few
highly related firms are combined with many low-related firms, assure the
highest efficiency of a supply chain. This paper studies the network topology
that leads to the highest agility of the supply chain when sudden demand
changes occur. To do this, an agent-based model of a supply chain with
restricted relationship between agents is built. The model includes three
tiers, where the flow of material is distributed from the bottom supplier to
the final customer passing necessarily through firms in every tier. Agility is
measured in the model simulations through the order fulfillment rate. Unlike to
previous theoretical and lab results, the simulation of the model shows that
the highest levels of agility are not obtained with a scale-free topology.
Instead, homogeneous distribution of links, such as those induced by regular or
Poisson probability laws, shows higher agility values than heterogeneous
distributions. Other previous recommendations, such as redundancy or having
multiple suppliers, are confirmed by the simulations. The general conclusion is
that the most suitable network topology in terms of agility depends on the
specific conditions of the supply chain and the aspects of the performance to
be analyzed.
