Abstract: Methods and test systems for reporting transmit bandwidth contention. A histogram representing transmit bandwidth demand for a network device may be built, the histogram including a plurality of bins representing for a plurality of contiguous time intervals of equal duration including a current time bin and plural future time bins. The histogram may be displayed and periodically updated.

Abstract: An impairment unit, method, and machine readable storage media for emulating network impairments. A first network interface may receive network traffic including a plurality of received packets. A classifier may determine an impairment class of each received packet based on test information contained within a payload portion of each received packet, the impairment class of each received packet being one of a plurality of impairment classes, each impairment class uniquely associated with a corresponding one of a plurality of impairment profiles. An impairment engine may impair each of the plurality of impairment classes in accordance with the corresponding impairment profile to provide impaired network traffic. A second network interface may transmit the impaired network traffic to the network.

Abstract: Methods, apparatus, and computer readable storage media for accumulating traffic statistics. A traffic receiver may receive a packet and determine a flow identifier associated with the received packet. A hash function may be applied to the flow identifier to generate a memory pointer. One or more records may be retrieved from a statistics memory based on the memory pointer. A determination may be made if the flow identifier associated with the received packet matches a flow identifier value contained in one of the one or more retrieved records. When a match occurs, the retrieved record containing the matching flow identifier value may be updated and the updated record may be stored in the statistics memory.

Abstract: Methods and test systems for reporting transmit bandwidth contention. A histogram representing transmit bandwidth demand for a network device may be built, the histogram including a plurality of bins representing for a plurality of contiguous time intervals of equal duration including a current time bin and plural future time bins. The histogram may be displayed and periodically updated.

Abstract: An impairment unit, method, and machine readable storage media for emulating network impairments. A first network interface may receive network traffic including a plurality of received packets. A classifier may determine an impairment class of each received packet based on test information contained within a payload portion of each received packet, the impairment class of each received packet being one of a plurality of impairment classes, each impairment class uniquely associated with a corresponding one of a plurality of impairment profiles. An impairment engine may impair each of the plurality of impairment classes in accordance with the corresponding impairment profile to provide impaired network traffic. A second network interface may transmit the impaired network traffic to the network.

Abstract: Methods, apparatus, and computer readable storage media for accumulating traffic statistics. A traffic receiver may receive a packet and determine a flow identifier associated with the received packet. A hash function may be applied to the flow identifier to generate a memory pointer. One or more records may be retrieved from a statistics memory based on the memory pointer. A determination may be made if the flow identifier associated with the received packet matches a flow identifier value contained in one of the one or more retrieved records. When a match occurs, the retrieved record containing the matching flow identifier value may be updated and the updated record may be stored in the statistics memory.

Abstract: A method and apparatus for measuring network performance. A stream of packets of encoded data, sent by a transmitter across a network, are received. The stream of packets includes (n+1) packets having transmittal timestamps from a clock local to the transmitter, where n is an integer greater than or equal to one. An (n+1)th transmittal timestamp and an nth transmittal timestamp are determined. A value is calculated based on the (n+1)th and the nth transmittal timestamps. The value corresponds to the size of a virtual buffer needed to store the packets during a measurement interval. The value is used to determine a performance measure for the network.

Abstract: A method and apparatus for measuring network performance. A packet from a stream of multimedia data packets is received from across a network during a measurement interval. The time interval from the start of the measurement interval to receiving the packet is measured. The response of a buffer to the received packet is determined. The level of the buffer just before the packet arrives is calculated, based on the time interval. The level of the buffer just after the packet arrives is calculated, based on the previous level. A performance measure for the network is determined based on at least one of the two levels.

Abstract: A method and apparatus for measuring network performance. A packet from a stream of multimedia data packets is received from across a network during a measurement interval. The time interval from the start of the measurement interval to receiving the packet is measured. The response of a buffer to the received packet is determined. The level of the buffer just before the packet arrives is calculated, based on the time interval. The level of the buffer just after the packet arrives is calculated, based on the previous level. A performance measure for the network is determined based on at least one of the two levels.

Abstract: A method and apparatus for measuring network performance. A stream of packets of encoded data, sent by a transmitter across a network, are received. The stream of packets includes (n+1) packets having transmittal timestamps from a clock local to the transmitter, where n is an integer greater than or equal to one. An (n+1)th transmittal timestamp and an nth transmittal timestamp are determined. A value is calculated based on the (n+1)th and the nth transmittal timestamps. The value corresponds to the size of a virtual buffer needed to store the packets during a measurement interval. The value is used to determine a performance measure for the network.