  A new approach of coordination of decisions in a multi site system is
proposed. It is based this approach on a multi-agent concept and on the
principle of distributed network of enterprises. For this purpose, each
enterprise is defined as autonomous and performs simultaneously at the local
and global levels. The basic component of our approach is a so-called Virtual
Enterprise Node (VEN), where the enterprise network is represented as a set of
tiers (like in a product breakdown structure). Within the network, each partner
constitutes a VEN, which is in contact with several customers and suppliers.
Exchanges between the VENs ensure the autonomy of decision, and guarantiee the
consistency of information and material flows. Only two complementary VEN
agents are necessary: one for external interactions, the Negotiator Agent (NA)
and one for the planning of internal decisions, the Planner Agent (PA). If
supply problems occur in the network, two other agents are defined: the Tier
Negotiator Agent (TNA) working at the tier level only and the Supply Chain
Mediator Agent (SCMA) working at the level of the enterprise network. These two
agents are only active when the perturbation occurs. Otherwise, the VENs
process the flow of information alone. With this new approach, managing
enterprise network becomes much more transparent and looks like managing a
simple enterprise in the network. The use of a Multi-Agent System (MAS) allows
physical distribution of the decisional system, and procures a heterarchical
organization structure with a decentralized control that guaranties the
autonomy of each entity and the flexibility of the network.
