es in the operator network. How distribution considerations affect the service network can, however, be dealt with separately (see Sect. 6.2.7), once the non-distributed PCS is understood. Our first consideration is how the information of the resource model for the RS shall be distributed over the PCS. This comprises both fragmentation and abstraction of the RS model. Figure 6.7 suggests partitioning the model into five fragment types: SW (two identical instances, SW1 and SW2), a number of access routes (AR), core routes (CR), CNUs and TRs. Model abstraction is applied in two steps: a connection network model (CNW) and a teleservice network model (TNW). All these models are service resource models. 6.2 A Service Network Modelling Case Teleservice Controllers (TEC) Process Teleservice Process Control Controller (TEPC) System (PCS) Teleservice Resource Models Connection Service controllers Process Controller (CNPC) Partition and abstract the RS model AccRoute CoreRoute Controllers Controller Manager Manager Controller Resource System service resource service single service relation multiple service relations multiple service relations model object (provider-user) (many users) (many providers) Fig. 6.7 A centralized solution to the network process controller A service resource model is a common model for the provider and the user of a service, which is why I (as a first step) associate the models to the service relations between service objects in the model. A service resource model defines the resources that are handled by the service-providing object, on some level of abstraction. Thus, a service resource model defines what the provider and the user can talk about. In other words, it is the "universe of discourse" for communication between provider and user. The providing object might have to handle less- abstracted models on a lower level. For example, the TEPC and the CNPC have a simplified model (CNW) of the connection network in common. The CNPC there- fore must be able to map the CNW model on the more detaile