Abstract: An apparatus that searches for a pattern in a signal is disclosed. The apparatus can be used to implement a real time trigger in an instrument such as a high speed oscilloscope. The apparatus includes a symbol generator and a finite state machine (FSM). The symbol generator receives an ordered sequence of signal values and converts the ordered sequence of signal values into an ordered sequence of symbols, each symbol having a plurality of states. The FSM receives the ordered sequence of symbols and generates a match signal if the ordered sequence of symbols includes a target sequence specified by a regular expression that includes a counting limitation on one of the symbol states. The FSM includes a counting state that includes a counter that counts instances of the one of the symbol states.

Abstract: The present invention provides an assay device for detecting an analyte in a fluid sample, comprising: a sample receiving member (1), which is fluidically connected to at least two components (2, 3) defining an assay flow path, at least one of which is a detection member (3) comprising an analyte detection zone (31); and a sample detection element (13) adapted to detect fluid at a particular point along the assay flow path. The present invention also provides the use of the assay device of the invention for indicating sample sufficiency when the assay device is exposed to a fluid sample and for indicating to a user after sampling that the device has failed due to insufficient sampling, and a method of alerting a user to the fact that a sufficient sample has been applied to an assay device of the invention.

Abstract: An apparatus that searches for a pattern in a signal is disclosed. The apparatus can be used to implement a real time trigger in an instrument such as a high speed oscilloscope. The apparatus includes a symbol generator and a finite state machine (FSM). The symbol generator receives an ordered sequence of signal values and converts the ordered sequence of signal values into an ordered sequence of symbols, each symbol having a plurality of states. The FSM receives the ordered sequence of symbols and generates a match signal if the ordered sequence of symbols includes a target sequence specified by a regular expression that includes a counting limitation on one of the symbol states. The FSM includes a counting state that includes a counter that counts instances of the one of the symbol states.

Abstract: The present invention provides an assay device for detecting an analyte in a fluid sample, comprising: a sample receiving member (1), which is fluidically connected to at least two components (2, 3) defining an assay flow path, at least one of which is a detection member (3) comprising an analyte detection zone (31); and a sample detection element (13) adapted to detect fluid at a particular point along the assay flow path. The present invention also provides the use of the assay device of the invention for indicating sample sufficiency when the assay device is exposed to a fluid sample and for indicating to a user after sampling that the device has failed due to insufficient sampling, and a method of alerting a user to the fact that a sufficient sample has been applied to an assay device of the invention.

Abstract: A method for real time monitoring of at least one TCP flow involves monitoring TCP packets flowing past a particular point in a TCP network. A flow trace including at least source and destination addresses for each TCP packet is determined and a packet record for each monitored TCP packet within a determined flow trace is created. Each of the packet records includes at least a transmitted order number and an actual received sequence number, from which an expected received sequence number for each packet record is determined and stored in the packet record. The difference between the expected received sequence number for each packet record and the expected received sequence number for the previous packet record is used to thereby determine by how much a particular packet was moved out of sequence.

Abstract: A communications apparatus is capable of being disposed in-line in a communications link that supports a main communications channel. The communications link connects a first host to a second host. The communications apparatus comprises an application logic that supports a sub-channel within the main channel. When the main channel is potentially faulty, the application logic is arranged to monitor the main channel to determine an error condition and send a message by replacing data reserved for control purposes in order to communicate the error condition as sub-channel data.

Abstract: In a packet switched network, network data can be recorded for measurement by transmitting a measurement packet across the network to store path records as it travels from an originating measurement device to a destination device. Some of the network devices located along the path traversed by the measurement packet are capable of recognizing that the measurement packet no longer has any further storage capacity for path records. The network device then copies or clones the measurement packet and erases the path record data from the original measurement packet. The original measurement packet then continues on its path to the destination address collecting further path records on the way, while the cloned packet is returned to the measurement host for processing of the path records when all cloned packets and the original measurement packet return to the measurement host.

Abstract: An in-line network simulator is provided that disrupts packets traveling through it to simulate network conditions. According to one embodiment, a method comprises receiving, at an in-line network simulator, packets sent from a source node to a destination node. The in-line network simulator classifies the received packets into respective ones of a plurality of different classifications, and disrupts the received packets based on corresponding disruption characteristics defined for their respective classifications. Such disrupting of the packets may include selectively performing at least one of delaying, dropping, and reordering of the received packets.

Abstract: A monitoring apparatus for detection of a malicious attack in a communications network comprises a pattern matching engine (406), a data store (408) and an alert generator (410, 412). The pattern matching engine (406) is arranged to receive a bit stream and identify a characteristic of a malicious attack from at least one datagram represented by at least part of the bit stream. The data store (408) is operably coupled to the pattern matching engine and the data store (408) is arranged to retain identification data to enable the pattern matching engine to identify the characteristic of the malicious attack. The alert generator (410, 412) is arranged to generate an alert in response to an identification of the characteristic of the malicious attack. The data store (408) is remotely updatable.

Abstract: A communications apparatus is capable of being disposed in-line in a communications link that supports a main communications channel. The communications link connects a first host to a second host. The communications apparatus comprises an application logic that supports a sub-channel within the main channel. When the main channel is potentially faulty, the application logic is arranged to monitor the main channel to determine an error condition and send a message by replacing data reserved for control purposes in order to communicate the error condition as sub-channel data.

Abstract: A method for real time monitoring of at least one TCP flow involves monitoring TCP packets flowing past a particular point in a TCP network. A flow trace including at least source and destination addresses for each TCP packet is determined and a packet record for each monitored TCP packet within a determined flow trace is created. Each of the packet records includes at least a transmitted order number and an actual received sequence number, from which an expected received sequence number for each packet record is determined and stored in the packet record. The difference between the expected received sequence number for each packet record and the expected received sequence number for the previous packet record is used to thereby determine by how much a particular packet was moved out of sequence.

Abstract: A network topology map and a system and method of annotating a network topology map of a packet network is described which monitors traffic engineering extensions in link state advertisement packets. Traffic engineering information contained in traffic engineering extensions is extracted and the traffic engineering information is used to annotate the network topology map with network attributes, such as bandwidth information and traffic engineering metrics.

Abstract: An in-line network simulator is provided that disrupts packets traveling through it to simulate network conditions. According to one embodiment, a method comprises receiving, at an in-line network simulator, packets sent from a source node to a destination node. The in-line network simulator classifies the received packets into respective ones of a plurality of different classifications, and disrupts the received packets based on corresponding disruption characteristics defined for their respective classifications. Such disrupting of the packets may include selectively performing at least one of delaying, dropping, and reordering of the received packets.

Abstract: A monitoring system comprises a first network probe coupled to a first point in a communications link and a second network probe coupled to a second point in the communications link. Each of the first and second network probes is arranged to sample packets from a predetermined flow of packets and store timestamps associated with packet samples. The timestamps stored by the probes are subsequently correlated.

Abstract: In a packet switched network, network data can be recorded for measurement by transmitting a measurement packet across the network to store path records as it travels from an originating measurement device to a destination device. Some of the network devices located along the path traversed by the measurement packet are capable of recognizing that the measurement packet no longer has any further storage capacity for path records. The network device then copies or clones the measurement packet and erases the path record data from the original measurement packet. The original measurement packet then continues on its path to the destination address collecting further path records on the way, while the cloned packet is returned to the measurement host for processing of the path records when all cloned packets and the original measurement packet return to the measurement host.

Abstract: A network-wide set of paths potentially taken by packets in a communications network is identified by collecting packets containing information indicative of the interconnection of the network, and of its interconnection with other networks. The contents of the collected packets are used to identify the network-wide set of routers and sub-networks and their interconnections, which are traversed by communications within the network. An output is provided that is indicative of any selected part of the network-wide set of routers and sub-networks and their interconnections.

Abstract: A network element is provided with the capability to perform monitoring and/or measurement functions on the element and the network of which it is a part. The monitoring/measurement functionality is implemented by programmable devices to enable the functionality to be modified and updated without removing the network element from service.

Abstract: A single probe collects link state routing protocol data for two or more areas. The areas may be located within one autonomous system or divided among multiple autonomous systems. Each autonomous system operates pursuant to a link state routing protocol. A router in each area is selected to share its link state routing protocol data with the probe. A logical connection is established between each selected router and the probe. The probe will begin the process of obtaining the routing information by creating an adjacency or partial adjacency with each selected router. The probe will receive link state routing protocol data from each selected router once adjacency is established. Alternatively a router in each area to be monitored is selected, and the probe polls the selected routers periodically for the appropriate SNMP MIB tables. The probe decodes the MIB data to obtain the link state routing protocol data.