 to the event dispatcher, the applet is ready to receive events. When any event reaches the event dispatcher, the event dispatcher stores the event in an event database and sends the event to the connected clients (see Figure 14.4). When the applet receives the event, using HTTP, it activates a CGILua script that accesses the event database and rebuilds the page containing the event list. This access to the event database is required because alarms which were previously active may have been eliminated, by the correlation mechanism, with the reception of the new event. For example, link up alarms can eliminate link down alarms of the same network interface. In contrast to many web-based management applications, WebComm does not use the applet as the graphical interface to display the event list. Its graphical interface is HTML-based. In the event manager screen, events are sorted as they are received. Some fields of the X.733 standard format are exhibited, for instance the severity, which determines the row colour. Similar events are filtered and the number of similar events is exhibited in the column count. The field event time displays the date of the latest event. The traffic monitor interface allows the user to see statistical graphs describing input and output activity at each interface in managed network devices. 14 Web-based Telecommunications Systems Management The traffic monitor is based on the Monitoring Service. The user determines whether host traffic is monitored at that host, when adding a host to the network diagram. If so, then a monitor is chosen to be reconfigured in order to also monitor all the interfaces in the new host. Mechanisms for choosing monitors which keep the load balanced between them are issues for future study. Traffic information is collected from managed devices through SNMP at 5-minute intervals and stored in a database. This information can be displayed on various temporal scales. 14.3.4 Summary of WebComm Services The main services offered by WebComm are asynchronous event re