Network Physics, Inc.

Other

Opnet Technologies, Inc.

Networks Physics, Inc.

Minh Duong-van

Han C Wen

Tomas J Pavel

Mark E Crane

Ian Adam

Gilbert Grosdidier

Richard Blankenbecler

Richard Blanckenbecler

Thomas J Pavel

A control node of a communication network is operated at a packet bandwidth determined according to observations of performance metrics of the network at the control point. These performance metrics may be one or more of throughput, average fetch time and packet loss. The control node is operated so as to set a control bandwidth to corresponding resonance points of the performance metrics. The resonance points are determined by scanning across a range of control bandwidths, until one or more of the performance metrics is/are optimized. The packet bandwidth is set by varying an inter-packet delay time over selected communication links at the control node.

Method of reducing packet loss by resonance identification in communication networks

Predictions of congestion conditions for a traffic stream in a communication network are applied to modify an initial congestion window size for the traffic stream; and dynamic bandwidth control is thereafter applied to the traffic stream. This dynamic bandwidth control may include modulating inter-packet bandwidths of the traffic stream according to a capacity of a bottleneck in a communication path through which the traffic stream passes in the communication network. The predictions of congestion conditions may be based on monitoring packet losses and/or round trip times within the communication network for a selected period of time. The monitoring may be performed on at least one of a traffic stream-by traffic stream basis, a connection-by-connection basis, a link-by-link basis, or a destination-by-destination basis.

Method for accelerating TCP flows in communication networks with dynamic control

Packet round trip times (RTT) within a communication network are measured and from those measurements information regarding congestion conditions within the network is extracted. The RTT measurements are organized into an invariant distribution (a histogram) and an analytical tool which is designed to reveal periodicity information (such as a Fourier or wavelet transform, etc.) is applied to the distribution to obtain a period plot. From this period plot, bandwidth information (indicative of the congestion conditions and/or link capacities within the network) can be obtained.

Method for determining network congestion and link capacities

A buffer size for a router configured to receive packets transmitted through a communications network is temporarily increased at a time instant corresponding to an onset of congestion of the router for a time period that may be approximately equal to a round-trip packet time in the network. The increase in buffer size may be accomplished by providing an auxiliary storage area for packets that would otherwise be stored in a queue at the router, for example an auxiliary storage area associated with a physical storage device external to the router.

Method for controlling congested network flow

Congestion within a traffic stream of interest in a communication network is characterized as self-induced congestion or cross-induced congestion by analyzing a correlation result of a time series of throughput data of the traffic stream of interest and making the characterization based on power spectrum features found in the correlation result. The correlation result may be obtained through a Fourier analysis, a wavelet analysis or any mathematical process based on locating periodicities in the time series. In some cases, the characterization is made at a node in the communication network that is downstream from the congestion, while in other cases, the characterization is made at a node in the communication network that is upstream of the congestion.

Method for dynamical identification of network congestion characteristics

Congestion within a communication is controlled by rate limiting packet transmissions over selected communication links within the network and modulating the rate limiting according to buffer occupancies at control nodes within the network. Preferably, though not necessarily, the rate limiting of the packet transmissions is performed at an aggregate level for all traffic streams utilizing the selected communication links. The rate limiting may also be performed dynamically in response to measured network performance metrics; such as the throughput of the selected communication links input to the control points and/or the buffer occupancy level at the control points. The network performance metrics may be measured according to at least one of: a moving average of the measured quantity, a standard average of the measured quantity, or another filtered average of the measured quantity. The rate limiting may be achieved by varying an inter-packet delay time over the selected communication links at the control points. The control points themselves may be located upstream or even downstream (or both) of congested nodes within the network and need only be located on only a few of a number of communication links that are coupled to a congested node within the network. More generally, the control points need only be associated with a fraction of the total number of traffic streams applied to a congested node within the network.

Method for reducing fetch time in a congested communication network

End-to-end packet losses of one or more traffic streams transmitted across a congested network may be reduced by setting the bandwidths of the corresponding traffic streams at critical values thereof at one or more control points along the network topology. The critical value of the bandwidths may be determined by monitoring buffer occupancy at the control point(s). Buffer occupancy may be determined by periodically sweeping down from a maximum bandwidth value according to a monotonically decaying exponential function.

Method for reducing packet loss by phase transition identification in communication networks

End-to-end packet losses of one or more traffic streams transmitted across a congested network may be reduced by modulating the bandwidths of the corresponding traffic streams applied to node(s) of the network from one or more control points along the network topology. This reduction in packet loss results in a reduction in fluctuations or variability of the controlled traffic streams, an increase in bandwidth utilization and a reduction in times to transmit files. The control points can be either upstream or downstream of one or more congestion points along the network. The modulation of the bandwidths are governed by a nonlinear differential equation that involves feedback of the throughput and buffer occupancy level. The control terms involve a relaxation time, coupling constant, control constant and nonlinear feedback constants.

Method for reducing packet loss and increasing internet flow by feedback control

A queue length for a queue storing packets transmitted through a communications network is temporarily increased at a time instant corresponding to an onset of congestion of the queue for a time period. Increasing the queue length in this way may be accommodated by providing an auxiliary storage area for packets that would otherwise be stored in the queue. The auxiliary storage area may be associated with a different physical storage device than a storage device associated with the queue.

Method for reducing excess queue time in communication nodes

An electrosurgery blade active electrode having a plurality of discrete electrical discharge points along a blade edge. A plurality of distinct points are provided for current discharge, facilitating controlled evenly distributed current through the tissue. The more stable discharge allows cutting with reduced current thus substantially reducing problems of the electrode sticking to the tissue and reducing damage to surrounding tissue. Furthermore, the cutting speed is increased and the smoke generated in the cutting process is decreased with use of the inventive blade. The electrosurgery blade of the invention may also include a plurality of grooves or channels on the side of the blade leading from the blade edge to the back of the blade away from the cutting edge to facilitate the escape of heated gasses from the area of the cut.

Electrosurgery blade having discrete point discharge saw-tooth edge

A tennis racket with handle and head coupled with an interconnection insert provides torsional elasticity and vibration damping. The racket handle has a mating extension extending toward the head and the head includes a mating extension extending toward the handle such that the handle and head mate together at the mating extensions. The handle extension has a tongue with two bores and a pair of elastic bushings extending through bores. The head mating extension comprises a recess or U-shaped channel which receives the tongue and includes a pair of securing pins extending through the bushings and being rigidly secured to the sides of the recess or channel. The bushings and pins are positioned transverse to the longitudinal extent of the handle and parallel to the racket face. The bushings perform a shock absorbing function, provide torsional elasticity and control the racket stiffness. A stabilizing bushing may be added parallel to the first two bushings and it extends through the tongue and through the sides of the recess or channel. A stabilizing pin then extends through this bushing.

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Menlo Park, CA, United States of America

Minh Duong-van