Networks are considered as a set of all their nodes, connections, hardware, software and personnel (users, administrators and managers), participating in the realization of distributed tasks. The networks are operating in an often hostile environment, exposed to such threats as attacks, viruses and human faults. System (network) dependability is discussed with respect to the occurrence of these incidents and their consequences on data flow capabilities.

The maintenance policy system is based on a 3-phase system renewal: detection, failure isolation, repair. The isolation process is performed by reconfiguring the dataflow routes and local storing of data. Repair includes information restoration and redistributing the locally stored data.

The paper proposes a framework for developing the network maintenance policy based on the cost of implementing the various feasible rules. A procedure for determining this cost is discussed. Some useful cost relationships are identified, justifying the need for such approach.