ith regard to functionalities in the application. For example, with fault func- tionality, some users can only view the logs, others can view and edit the logs, yet another group or user in a group can even delete logs. With single- sign-on (SSO) functionality implemented at NMS, a single authentication should permit the user working on NMS to jump to the console of any net- work element that is managed or any element management application that is associated with the NMS. Download additional records and configuration data: Any other record in the element that is required by some functionality at NMS is also down- loaded from the network element. Predefined configuration data, like cor- relation between performance registers or rules for event handling are also downloaded. Once the resources are discovered and the historical data downloaded, then the NMS application is ready for performing any maintenance level activities. The maintenance activities or network functions are performed with the down- loaded data. These functions will include network provisioning, troubleshooting of network issues, maintenance of configured network elements, tracing the flow of data across multiple network elements, programming the network for optimal utilization of elements, and SO on. During a connection loss between the NMS and an already managed element, the NMS will try for a connection 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