to be discovered. A discovery.log file records the discovery process. Fundamentals of EMS, NMS and OSS/BSS 2. Polling (daemon process: OpenNMS.Pollerd: This process is used to find the status of a discovered service. An attempt is made to establish connection with the service, and failure to connect leads to retry for connection. The retry is only performed a predefined number of times and a timeout interval deter- mines how much time to wait for a response from the service. Configuration of the poller can be performed by making changes in poller-configuration.xml file. The poller also has special models to handle polling when a service goes down, like a higher polling frequency initially expecting the service to come up and then a lower frequency in polling. 3. Notification (daemon process: OpenNMS.Notifd: As the name suggests, the purpose of this process is to notify the user about an event. There are multiple methods available in OpenNMS to send notifications. E-mail and paging are the most common methods of issuing notifications to a physical user. Mechanisms that employ XMPP and SNMP traps are available for sending notification to another application and HTTP GET/POST can be used to send notifications to a Web site. The notification is usually a text message with details on the event that triggered the notification, along with information on the node that caused the event. When the notification method employed is e-mail, then a subject line is also introduced. Notification can be issued to users (users.xml), groups (groups.xml), or configured roles. Additional capabilities include the capability to add escalations when a notification is not acknowledged and to introduce a delay before sending notification. Notifications have a unique id. 4. Data collection (daemon process: OpenNMS.Collectd: SNMP was the only data collection method supported previously by OpenNMS to collect data from the network elements from southbound interface. A majority of the data processing functions including certain performance repor