3com Corporation

David James Stevenson

Robert Duncan

Andrew Hunter Gray

Christopher Robert Linzell

Alastair Hugh Chisholm

Iain Hogg

Neil William Gray

Vanessa Serra

Colin Tinto

Hamish Donald Stuart Martin

Hamish D S Martin

Ronan François Daniel Grandin

Jonathan Gilbert Gordon Tams

Ronan Fran&ccedil;ois Daniel Grandin

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.

Testing applications or devices in large networks

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.

Apparatus and method for processing data relating to events on a network

A method and apparatus for determining a time interval for periodically polling a device on a networkis described. The method determines the most restrictive link on the path to the network device, the level of restrictiveness of a link being dependent on the nature of the link, such as the link speed and link type. The time interval between polling is determined based on the nature of the most restrictive link. Thus, the time interval can be determined according to the type and speed of the links between the polling device, which in a preferred embodiment is a network management station, and the polled device on the network

Method and apparatus for determining a polling interval in a network management system

In a network of managed devices, a method of processing network events to reduce the number of events to be displayed in an event log, comprising receiving information relating to network events, passing information regarding a network event to an event processor, determining if the information passed to the event processor relates to a type of event processed by that event processor, and if it is of such a type, processing said information if information on a related event has already been received by that event processor. The method also includes passing said information on to a further event processor if the information received does not relate to a type of event processed by said first event processor. A set of event processors for carrying out the method is described together with a computer program, or a program on a computer readable medium loadable into a digital computer, or embodied in a carrier wave, which computer program operates in accordance with the method.

System using a series of event processors for processing network events to reduce number of events to be displayed

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.

Network management apparatus and method for identifying causal events on a network

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.

Method and apparatus for fetching sparsely indexed MIB tables in managed network systems

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.

Management system and method for monitoring stress in a network

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.

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Edinburgh, United Kingdom

David James Stevenson