Abstract: Route asymmetry is detected in a network by running a route tracing program to trace routes between a first element of the network and a second element of the network. The route tracing program need be run at only a single network element, such as the first network element. Forward and reverse routes between the first and second network elements are identified as asymmetric if performance data from the route tracing program indicates a significant deviation from an expected monotonic characteristic as a function of time-to-live values of respective packets transmitted by the route tracing program.

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 technique for ensuring that a node that carries high-priority protocol data units and low-priority protocol data units is properly configured to accord the high-level protocol data units priority treatment is described. In accordance with the illustrative embodiment, two streams of protocol data units are transmitted through a node to be tested. One stream comprises high-priority protocol data units, and the second stream comprises low-priority protocol data units. The processing capabilities of the node are then burdened by increasing the frequency of protocol data units transmitted to it, so that the node is compelled to treat the two streams differently, if, in fact, it is properly configured to treat them differently. If the node treats the two streams differently and accords the high-priority stream higher priority, then the node is properly configured. Otherwise, the node is re-configured to accord the high-priority stream higher priority.

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 technique for ensuring that a node that carries high-priority protocol data units and low-priority protocol data units is properly configured to accord the high-level protocol data units priority treatment is described. In accordance with the illustrative embodiment, two streams of protocol data units are transmitted through a node to be tested. One stream comprises high-priority protocol data units, and the second stream comprises low-priority protocol data units. The processing capabilities of the node are then burdened by increasing the frequency of protocol data units transmitted to it, so that the node is compelled to treat the two streams differently, if, in fact, it is properly configured to treat them differently. If the node treats the two streams differently and accords the high-priority stream higher priority, then the node is properly configured. Otherwise, the node is re-configured to accord the high-priority stream higher priority.

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: Techniques for determining a problem location or otherwise characterizing a network comprising a plurality of processing elements, including at least one processing element associated with performance of a packet encapsulation operation of an encapsulation protocol. The packet encapsulation operation is performed on a test packet to generate an encapsulated packet, the test packet having a time to live (TTL) value and an identifier. In conjunction with performance of the packet encapsulation operation, the TTL value and the identifier of the test packet are copied to a header of the encapsulated packet. The encapsulated packet is transmitted, and a determination is made as to whether a reply packet has been received responsive to transmission of the encapsulated packet. The reply packet, if any, is processed to obtain information utilizable in determining the problem location or otherwise characterizing the network.

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: 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: Route asymmetry is detected in a network by running a route tracing program to trace routes between a first element of the network and a second element of the network. The route tracing program need be run at only a single network element, such as the first network element. Forward and reverse routes between the first and second network elements are identified as asymmetric if performance data from the route tracing program indicates a significant deviation from an expected monotonic characteristic as a function of time-to-live values of respective packets transmitted by the route tracing program.