ent. Similarly, CRM will have activities like order management, trouble ticket management, contract management, and SLA breach management. 2. OSS (operation support systems): These are solutions that handle service management. It includes functions like service assurance, manage services reporting, and SO on. In most discussions where OSS is mentioned, it is the service management that is the key focus and not any type of support sys- items. So OSS can be used in the context of any type of support system or to specifically mean service oriented solutions. It is also referred to as "service OSS" to avoid the ambiguity in usage of OSS as the holistic support system. 3. NMS (network management system): These are solutions that handle man- agement of network resources. From support system perspective the element managers are components of the master network manager and the element management layer is embedded in NMS functionality. Network OSSs (NMS) manage specific elements in the network deployed by the operator. NMS solutions are optimized to manage as specific service equipment or a server infrastructure. For example, an NMS for broadband services will be optimized for broadband infrastructure like ATM, Frame relay, or DSL and an NMS for a specific server infrastructure would be optimized for servers like Sun Solaris, HP Unix, or Apache Web Server. The service OSS is the binding glue between the BSS and NMS domains (see Figure 19.2). There needs to be seamless flow of data between business solutions, service solutions, and network solutions in support systems for a service provider. Business support systems (BSS) Operational support systems (OSS) (Service OSS) Network management system (NMS) (Network OSS) OSS landscape (Holistic support systems) Figure 19.2 OSS landscape. What Is OSS and BSS? Together these modules form the support system in the service provider space. Most service providers do an end-to-end (E2E) between these modules to bring down the operational expenditure (OPEX). 19.6 From TMN to eTOM In the 