he type of fault. Information is carried as objects. Any trap contains the information on: Device that has encountered a problem. Type of fault. Both the device and the agent sending the notification, if they are different. Time of fault. Possible variables that might have caused the problem and their values at the time the problem occurred, although this is not always possible depending upon the agent implementation. 12.4 TL1 Notifications The notifications received from TL1 devices are in the form of TL1 autonomous messages. Autonomous messages are received from TL1 devices without any com- mand being input from the fault management system. OSS for Telecom Networks The TL1 connection processes specified in the configuration file are started when the fault management system is started. This process reads the file which lists the devices to which the connection is to be established. Accordingly, TL1 fault manage- ment systems register to receive autonomous messages from the specified devices. The event process receives the autonomous message sent by the TL1 device and converts it into a fault event. This event is then passed through the event parser and emerges possibly after some modifications have been made by the event parser. The events leaving the parser are then processed by the event filters. Events which survive the filtration are stored in the event database. 12.5 Configuring Notification Reception FMS can be configured to receive SNMP notifications (traps) at one or more ports. The port(s) that are listening for traps are specified by entries in the trap port con- figuration file. When traps are received by FMS, other applications may be notified using the Trap Observer mechanism. Each application to be notified registers with the event manager as an Observer for Traps. Notification of traps are made in SNMP PDU form and contain Trap PDU information. When the management system is configured to listen for traps at a particular port, then no other application can listen for traps at that port. The Common 