, fulfillment, assurance and billing) and SIP make up the verticals in eTOM, there is a set of functional process structures that form the horizontals in eTOM. The top layer of the horizontal process group is market, product, and customer processes dealing with sales and channel management, marketing management, product and offer management, and operational processes such as managing the customer interface, ordering, prob- lem handling, SLA management, and billing. Below the customer layer is the process layer for service related processes. The process grouping of service processes deals with service development, delivery of service capability, service configuration, service problem management, quality anal- ysis, and rating. Below the service layer is the layer for resource related processes. The process grouping of resource processes deals with development and delivery of a resource, resource provisioning, trouble management, and performance manage- ment. The next layer is to handle interaction with supplier and partners. The pro- cess grouping of supplier/partner processes deals with the enterprise's interaction with its suppliers and partners. It involves processes that develop and manage the NGOSS supply chain, as well as those that support the operational interface with suppliers and partners. The entities with which the processes interact are also represented in the TOM model. The external entities of interaction are: Customers: The products and services are sold by the enterprise to customers. Suppliers: The services and resources used by the enterprise directly or indirectly to support its business are brought from a supplier. Partners: The enterprises with which a telecom enterprise cooperates in a shared area of business are partners of the telecom enterprise. Employees: These are human resources that work in the enterprise to meet the organizational goals of the enterprise. Shareholders: The people who have invested in the enterprise and thus own stock are the share holders of the enterprise. Stakehol