: 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 early 1980s most of the equipment required by local exchange carriers (LECs) were supplied by one or two suppliers in most parts of the world. One of the major changes to this approach was the breakup of the Bell System toward the mid-1980s after with LECs were encouraged to procure equipment from any vendor of choice. As a result the network for offering basic service now had components from mul- tiple vendors. While there were standard protocols for interaction between network elements from different vendors, there were no popular and adopted standards for telecom data and interface management in a multivendor environment. This led to an increase in CAPEX for having new support systems, increase 