ed NMS inventory database. The EMSs within a particular domain discover the inventory, configuration and topology information, which is then uploaded to respective domain managers. The domain managers store and maintain the intra-domain inventory. The legacy OSS is responsible for maintaining the inventory of the legacy network domain. The inter-domain manager maintains the domain information (not intra-domain data) and inventories Chapter 8 - Next-Generation OSS inter-domain links. The logical, integrated NMS database then provides an end-to-end view of the entire network, organized hierarchically and possibly realized via multiple physical stores. 3.1.2 Service Provisioning and Activation In the context of this chapter, service provisioning and activation is defined as, first, the assignment of appropriate network resources and then, configuration and programming of the network elements with the assigned and requested parameters in support of service delivery to a customer. The assignment and configuration of the network includes both physical elements - cable/pair, network links, network elements, slots, and ports - as well as logical elements - channels, virtual circuits, time-slots, and wavelengths. Figure 42 shows a simple service-provisioning scenario for a service that spans across three separate network domains. An example of such a service could be an IP-VPN service that uses DSL-based access, traverses over an IP core that is optically connected and requires dynamic provisioning. A service order manager or a workflow manager will generate a service-provisioning request when network resources need to be configured for the service. The Inter-Domain manager receives the request and designs the end-to-end service by assigning appropriate physical and logical resources, using the inter-domain inventory stored in the integrated NMS database. This assignment will include the domains involved, domain entry and exit points and logical channels across the domains. Based on this data, the inter-domain manager dec