tion establishment at regular intervals and synchronize the data when the connection is established. A rediscovery of the network resources and their states will also be performed at regular intervals to keep the most recent information at NMS. Fundamentals of EMS, NMS and OSS/BSS 11.3 Legacy NMS Architecture The architecture of NMS can be broken down into a set of building blocks. Any management solution that can collect data from network elements and performs one or more management functionality is an NMS. The data collec- tion may be limited to support for just a single protocol and the management function may be only fault handling or performance 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 