n enhanced version of these functionalities come up in the NMS layer. While EMS looks at fault data from a single element perspective, an NMS processes an aggre- gate of fault data from various NEs and performs operations using this data. Interface for web client Server Client EMS Server (FCAPS) Figure 1.2 Element management system architecture. Fundamentals of EMS, NMS and OSS/BSS Data collected by the EMS from the network elements are utilized by: NMS Server: The NMS uses collected as well as processed data from the EMS to consolidate and provide useful information and functionalities at a network management level. EMS Client: If data from EMS needs to be represented in GUI or as console output to a user then an EMS client is usually implemented for the same. The EMS client would provide help in representing the data in a user-friendly manner. One of the functions in 'F "C" APS' is configuring the network elements. The EMS client can be used to give a user-friendly interface for configuring the elements. Database (DB): Historical data is a key component in element management. It could be used to study event/fault scenarios, evaluate performance of the network elements, and SO on. Relevant data collected by EMS needs to be stored in a database. Interface for web client: Rather than an EMS client, most users prefer a light- weight, web-based interface to be a replacement for the web client. This func- tionality is supported by most EMS solutions. The EMS output could also be feed to other vendor applications. These exter- nal applications might work on part or whole of the data from the EMS. 1.4 Need for EMS The complexity of new services and the underlying network is increasing exponen- tially. At the same time there is a lot of competition among service providers offer- ing new and compelling services. This leads to the need for minimizing the cost of network operations. This can only be achieved if the elements in the network are well managed. The increase in complexity can be handled cost effectively only by 