 managed entity is in use. Since a detailed discussion of SID is outside the scope of this book, let's look into the basic building block, the domains in SID. Domains have the following properties: Domains are a collection of enterprise data and associated operations. Business entities in domains encapsulate both operations and enterprise information. They provide for robustness of corporate/enterprise data formats. The domains in SID are: 1. Market domain: This domain includes strategy and plans in the market space. Market segments, competitors, and their products, through to campaign for- mulation is covered in this domain. 2. Sales domain: This domain covers all sales related activity from sales contacts or prospects through to the sales force and sales statistics. Both the sales and marketing domain has data and contract operations that support the sales and marketing activities needed to gain business from customers and poten- tial customers. 3. Product domain: The information and contract operations related to product life cycle are covered in product domain. The ABEs in product domain deal with product planning, performance, offerings, and usage statistics of the products delivered to the customer. 4. Customer domain: All data and contract operations associated with indi- viduals or organizations that obtain products from a service provider are included here. It represents all types of interactions with the customer and management of customer relationship. The contract operations related to the Fundamentals of EMS, NMS and OSS/BSS customer bills for products, collection of payment, overdue accounts, billing inquiries, and adjustments made as a result of inquiries are all accounted in the customer domain. The customer domain maps to the customer layer in the eTOM model. 5. Service domain: This domain deals with the definition, development, and operational aspects of services. Various eTOM processes that deal with the definition, development, and management of services offered by an enterprise are supported 