Abstract: When testing network management applications, it is desirable to show that they will work with large or very large networks, to determine the upper bounds of the applications capabilities, and improvements which might increase the upper bounds. A method of testing a network application is disclosed mapping a layer-3 addresses of a real subnetwork onto a plurality of mapped layer-3 subnetwork addresses for conversations with applications or devices. Packets are modified to change a destination layer-3 address in a mapped subnetwork, pointing to corresponding real IP address and forwarding the packets. The conversation to which a response from a reallayer-3 address relates is identified. The source layer-3 address and packet contents are changed into the appropriate mapped subnetwork and the packet is forwarded to the application or device. An existing test network of any size may be used as the basis for testing the network management application.

Abstract: A network management apparatus and method processes network management data received during the monitoring of a network and generates events for presentation in an event list to a user when certain event conditions are detected. Network management data received in relation to an event condition is processed to determine whether it represents a recurring event condition. A recurring event condition is determined if a predetermined number of equivalent events have been generated, and appear in the event list, in an immediately preceding time period. In the described embodiment, if a recurring event condition occurs, a recurring event is generated, and subsequent occurrences of the event condition are not included in the event list presented to the user.

Abstract: A network management apparatus and method for identifying an event which is indicative of the underlying cause of more than one of a plurality of events detected by a network management station on a network is described in which the management station has knowledge of the topology of the network. Using the topology of the network, the apparatus and method considers the location of the network device causing each event in the plurality of events, and determines as the causal event, the event which has occurred at a location closest to the network management station. The method is preferably implemented in the form of a computer program.

Abstract: A method for fetching sparsely indexed MIB tables for a managed network device using an approximation operation, such as a GetNext SNMP operation, comprises sending a plurality of operations in a first data packet at least one of the plurality of approximation operations specifying a speculative approximation. By using speculative approximations of index values of data to be fetched, it is possible to retrieve MIB table data more quickly and efficiently.

Abstract: A system and method for providing a stress value representing the performance of a network comprising network devices is described. A raw data value for a monitored characteristic of a network device or link is obtained by the management system and compared with a predetermined threshold value for the monitored characteristic. If the raw data value is greater than or equal to said threshold value, the management system provides a stress value equal to a default value, said default value being a maximum or minimum value of a predefined bounded range; and if the raw value is less than said threshold value, the management system calculates a stress value within said predefined bounded range using an appropriate algorithm for said monitored characteristic.

Abstract: A network management apparatus and method for determining an optimum threshold value for a monitored characteristic of a network is described. The optimum threshold value is determined by counting a number of previously received events generated from values for a monitored characteristic which were above or below an existing threshold value for the monitored characteristic, and determining the optimum threshold value in dependence on the counted number. An optimum threshold value is provided, which is tailored to suit the network concerned.

Abstract: A network management apparatus and method processes network management data received during the monitoring of a network and generates events for presentation in an event list to a user when certain event conditions are detected. Network management data received in relation to an event condition is processed to determine whether it represents a recurring event condition. A recurring event condition is determined if a predetermined number of equivalent events have been generated, and appear in the event list, in an immediately preceding time period. In the described embodiment, if a recurring event condition occurs, a recurring event is generated, and subsequent occurrences of the event condition are not included in the event list presented to the user.

Abstract: A network management apparatus and method processes network management data in a network management system during the monitoring of a network. The apparatus and method considers whether the network management data indicates that the network condition of an event previously generated by the network management system is no longer present on the network, and therefore resolved. In a preferred embodiment, if the network management data indicates that a previous event has been resolved, the event is marked as resolved for presentation in an event list to the user. The user can then easily identify events which have been resolved.

Abstract: A network management apparatus and method is disclosed for determining an optimum threshold value for a monitored characteristic of a network. The optimum threshold value is determined by counting the number of previously received values for a monitored characteristic which values exceeded an existing threshold value for said monitored characteristic, and determining the optimum threshold value in dependence on the counted number. An optimum threshold value is provided, which is tailored to suit the network concerned.

Abstract: A method of monitoring a network of devices comprising defining at least two types of device, and monitoring the different types of device using different monitoring procedures, either interrogating said devices at different intervals or interrogating said devices using different protocols .The defined types of device comprise core devices and edge devices. The method also comprises determining the number of devices in the network to be monitored, and changing the monitoring intervals for each type of device in accordance with the determined number.