Abstract: One or more network elements that modify type of service values in a network are detected by sending route tracing messages having increasing time-to-live values and a designated type of service value from a first network element to a second network element. Type of service values are monitored in respective time exceeded messages received from respective network elements on a given network path between the first network element and the second network element responsive to the route tracing messages. At least a particular one of the network elements on the given network path that has made a modification in type of service value relative to the designated type of service value is identified, based on the monitored type of service values in the respective time exceeded messages.

Abstract: A network condition capture and reproduction technique captures measurement data characterizing network conditions at a given time between first and second endpoint devices of a network, and utilizes the captured measurement data in a network impairment device to reproduce the network conditions at a later time and possibly in a different place.

Abstract: An apparatus and method are disclosed that enable a first telecommunications endpoint to ensure that a second endpoint is receiving the first endpoint's packet stream transmissions with a satisfactory waveform quality. When the second endpoint receives the packet stream, it decodes the media waveform from the stream, encodes the waveform back into a second packet stream, and transmits some or all of the packets in the second stream back to the first endpoint. The first endpoint then decodes the received waveform in the second stream and compares it to the original waveform transmitted to the second endpoint. Based on the comparison, the first endpoint adjusts the value of a quality indication, and provides the quality indication to its user and to the second endpoint. Advantageously, the user at the second endpoint is able to determine whether the received waveform is, in fact, close enough to the waveform that the first endpoint's user intended to be received and understood.

Abstract: A method for estimating the network-layer topology of a telecommunications network is described. In particular, the illustrative embodiment of the present invention estimates the existence and connectivity of nodes in the topology based on the detection of network-wide end-to-end path intersections. This is based on the assumption that pairs of streams of packets that share a common node will interfere and that the interference can be detected in the received streams. In general, this interference is manifested as jitter. By transmitting streams on each pair of end-to-end paths in the network, and detecting interference (or a lack of interference) a matrix of path intersections for the network can be created. Using logic and supposition, the topology of the network can be estimated using the matrix of path intersections. Once the estimate of the topology is complete, the maintenance and operation of the network can proceed based on the topology.

Abstract: Node merging methods and apparatus are disclosed for generating simplified representations of network topology. A first topology representative of a given network is determined, and at least one pair of nodes of the first topology is merged into a single node based on measures associated with respective edges connecting the nodes of the node pair to at least one neighbor node common to that pair. The merging step is repeated for one or more additional pairs of nodes to produce a reduced network topology meeting one or more desired criteria, and a visualization or other representation of the reduced network topology is generated.

Abstract: One or more network elements that modify type of service values in a network are detected by sending route tracing messages having increasing time-to-live values and a designated type of service value from a first network element to a second network element. Type of service values are monitored in respective time exceeded messages received from respective network elements on a given network path between the first network element and the second network element responsive to the route tracing messages. At least a particular one of the network elements on the given network path that has made a modification in type of service value relative to the designated type of service value is identified, based on the monitored type of service values in the respective time exceeded messages.

Abstract: An apparatus and method are disclosed that enable a first telecommunications endpoint to ensure that a second endpoint is receiving the first endpoint's packet stream transmissions with a satisfactory waveform quality. When the second endpoint receives the packet stream, it decodes the media waveform from the stream, encodes the waveform back into a second packet stream, and transmits some or all of the packets in the second stream back to the first endpoint. The first endpoint then decodes the received waveform in the second stream and compares it to the original waveform transmitted to the second endpoint. Based on the comparison, the first endpoint adjusts the value of a quality indication, and provides the quality indication to its user and to the second endpoint. Advantageously, the user at the second endpoint is able to determine whether the received waveform is, in fact, close enough to the waveform that the first endpoint's user intended to be received and understood.

Abstract: A method for estimating the network-layer topology of a telecommunications network is described. In particular, the illustrative embodiment of the present invention estimates the existence and connectivity of nodes in the topology based on the detection of network-wide end-to-end path intersections. This is based on the assumption that pairs of streams of packets that share a common node will interfere and that the interference can be detected in the received streams. In general, this interference is manifested as jitter. By transmitting streams on each pair of end-to-end paths in the network, and detecting interference (or a lack of interference) a matrix of path intersections for the network can be created. Using logic and supposition, the topology of the network can be estimated using the matrix of path intersections. Once the estimate of the topology is complete, the maintenance and operation of the network can proceed based on the topology.

Abstract: A network condition capture and reproduction technique captures measurement data characterizing network conditions at a given time between first and second endpoint devices of a network, and utilizes the captured measurement data in a network impairment device to reproduce the network conditions at a later time and possibly in a different place.

Abstract: Node merging methods and apparatus are disclosed for generating simplified representations of network topology. A first topology representative of a given network is determined, and at least one pair of nodes of the first topology is merged into a single node based on measures associated with respective edges connecting the nodes of the node pair to at least one neighbor node common to that pair. The merging step is repeated for one or more additional pairs of nodes to produce a reduced network topology meeting one or more desired criteria, and a visualization or other representation of the reduced network topology is generated.