he consumption, build or sell inventory model used in other indus- tries, which was touched on at the beginning of this chapter, the telecom industry uses a reuse model. A reuse model is one in which inventory is re-used, requiring continuous management. To respond to new service requests, spare inventory is dis- persed throughout various field locations, central offices, mobile switching centres, cell sites, bay stations, maintenance garages, large customer equipment closets, trucks and so on. This requires inventory to be managed locally and interactively. Telcordia's Plug-in Inventory Control System and Detailed Continuing Property Record are designed to be used by the network management and engineering departments of a carrier. It enables an organization to track the inventory and invest- ment of plug-ins, capital tools, test sets and frame-mounted or "hardwired" Central Office Equipment (COE) in addition to any non-COE items that conform to COE-like accounting rules. 10.8.2 Visionael Inventory Management Visionael provides a good example of an inventory-centric OSS solution. Visionael is also widely regarded as one of the leaders in inventory management OSS. 33 The author was fortunate to be sent a large pack of materials from Visionael and also to be a regular visitor to their stand at the Telemanagement World Conferences in Nice. OSS for Telecom Networks Inventory of network equipment, facilities and circuits sits at the centre of the Visionael solution. The Visionael Repository is an inventory configuration and change management solution. The device library of the Visionael Repository is one of the most complete available and provides ready-to-use models of equipment. The device library provides the basis for Visionael's engineering design capabilities and its ability to present detailed physical and logical views of the network in historical, "as-built" or future states. Visionael can establish engineering rules and constraints, and also audit the net- work inventory against the current actual state of t