h time-based and multidata-based threshold rule setting is possible. Open source applications like "OpenNMS" provide all these functions and can be used as a framework for making specialized NMS for a particular network. Open source applications that offer just one specific management functionality is also available, like "Mandrax" or "Drools" for rule-based fault correlation. 11.7 GUI Components The GUI components are standard applications that convert the formatted data generated from management functional components to user-friendly graphical rep- resentations. For example performance records like link utilization data for a day monitored at regular intervals, would be easier to track and compare when plotted as in a graph. In similar lines the fault data will have a set of predefined fields, SO when the logs have to be presented to the user, it is best to format the logs and show the log contents under a set of header in an MS Excel format based GUI. The flow of data from NE to user through GUI components is shown in Figure 11.4. Some of the sample blocks in GUI components are: 1. Chassis viewers: The network elements usually in a COTS (commercial off- the-shelf) setup based on ATCA (advanced telecom computing architecture) specifications are usually placed in a chassis and connected using a physical medium to initiate interaction. The chassis will have a front end view and a back end view. On the NMS GUI, the user should be able to view where a particular element is placed in the chassis. So when a fault occurs on a par- ticular network element it would be easier to isolate the correct element in the chassis and perform debugging or replacement operation using the chassis diagram created using the interfaces offered by chassis viewer application. 2. Map viewers: When the network elements are spread across various geo- graphical locations as in a distrusted network environment, it would be Management collection function components components components Figure 11.4 Flow of data from NE to user. Fundamentals of