 handling, but it is still a valid NMS when the basic building blocks or a subset of the building blocks is present. The NMS architecture discussed in this section is called legacy NMS for a pur- pose. The old architecture used for the development of a network management sys- tem was not scalable, which led to work on new standards for developing NMS. AN NMS built using the guidelines of new standards is called next generation NMS and the old NMS systems that had become functionality rich with years of devel- opment is termed legacy NMS. Since this book will discuss next generation NMS, the term legacy NMS has been used from the beginning for the NMS architecture used currently in most solutions. The building blocks in legacy NMS are (see Figure 11.1): Platform components: These components include object persistence, logging framework, libraries, and SO on that are required by most of the management function implementation modules. Data collection components: Based on the NMS protocol supported on the network element, these components collect data from the network elements. In some management paradigms this component may not be part of the NMS and will be a separate solution called the EMS. Management function components: These components use the data collected from the network elements to provide FCAPS and other specialized manage- ment functionality. GUI components Management function components Data collection components Figure 11.1 Legacy NMS building blocks. What Is NMS? North bound interface (NBI) components: These components provide man- agement data to the north bound interfaces like another NMS or operations support systems (OSS). GUI components: These provide user interaction screens that enable a user to perform operations on the various modules in the NMS. These building blocks and the open source components that can be used in making these blocks are discussed in detail in the sections that follow. The data col- lection components can collect data directly from the network elements or from an EMS. In