339 results about "Slow-start" patented technology

A content-aware application switch and methods thereof intelligently switch client packets to one server among a group of servers in a server farm. The switch uses Layer 7 or application content parsed from a packet to help select the server and to schedule the transmitting of the packet to the server. This enables refined load-balancing and Quality-of-Service control tailored to the application being switched. In another aspect of the invention, a slow-start server selection method assigned an initially boosted server load metric to a server newly added to the group of servers under load balancing. This alleviates the problem of the new server being swamped initially due to a very low load metric compared to that of others. In yet another aspect of the invention, a switching method dependent on Layer 7 content avoids delayed binding in a new TCP session. Layer 7 content is not available during the initial handshaking phase of a new TCP session. The method uses the Layer 7 content from a previous session as an estimate to help select the server and uses a default priority to scheduling the transmitting of the handshaking packets. Updated Layer 7 content available after the handshaking phase is then used to reset the priority for the transmit schedule and becomes available for use in load balancing of the next TCP session.

Methods, apparatuses and systems directed to improving the efficiency of bandwidth allocation schemes by adapting to slow-start mechanisms associated with network communications protocols, such as the TCP/IP protocol suite. In one implementation, the present invention scales down the initial target rate assigned to a data flow to a fraction of an initial estimate of the effective rate capacity of the communications path between two hosts. As packets are received, the target rate is gradually increased, eventually up to the detected rate capacity of the communications path. Implementations of the present invention improve the efficiency of bandwidth allocation by reducing the over-allocation of bandwidth to data flows during the slow-start phase, leaving more bandwidth available to other data flows.

In the preferred embodiments, it is first determined whether or not a TCP connection from a sending device to a receiving device in the wireless communications network is in a slow start phase. If the TCP connection is in a slow start phase, then the data to be sent in the TCP connection that is allocated a priority that is higher than the priority allocated to other data to be sent by the sending device. The sending device may be a Serving GPRS Support Node (SGSN), a device in a Radio Access Network (RAN) or other network device, and the method of the preferred embodiments may be implemented by software installed and executed on the network device.

Methods and apparatus are described for intelligently assigning a portion of a cluster's traffic (e.g., buckets) to a cache system to minimize overloading of such cache system. In general terms, when a new cache system enters a cache cluster and/or starts up, the new cache system's full bucket allocation is not immediately assigned to the new cache system. Instead, only a portion of the full bucket allocation is initially assigned to the new cache system. In one embodiment, the new cache system's bucket assignment is gradually increased until the cache system is handling it's full bucket allocation or it becomes overloaded. The cache system's load is also checked periodically to determine whether it has become overloaded. When the cache system becomes overloaded, buckets are immediately shed from the cache system. In sum, the new cache system's load is adjusted until it is handling an optimum number of buckets.

The invention relates to a variable-frequency power source based on the control of a digital signal processor, which comprises a switch power source module, a control circuit, a circuit for isolating and shaping pulse-width modulating signal, IPM inverting circuits, a circuit for detecting and protecting busbar voltage, a rectification input slow-start circuit, a communication circuit, an interface circuit for isolating and inputting parallel signals and an human-computer interface circuit for displaying the key. The invention adopts the structure of a single digital signal processor (DSP) coupled with the double IPM inverting circuits, provides two paths of independent variable-frequency power sources for two sets of asynchronous motors at the same time and carries out independent speed regulations to the two sets of asynchronous motors. The variable-frequency power source of the invention has the advantages of small volume, low power consumption, high reliability and being convenient for bulk production, etc., and adopts an appropriate switch frequency and an advanced voltage space vector pulse width modulation algorithm (SVPWM), thereby lowering the noise during the operation of the asynchronous motors and increasing the voltage utilization rate, with obvious effect on energy saving.

A first loss determination section 13 of a first communication device 10 determines that a data unit is lost if an acknowledgment response for the transmitted data unit from a second communication device 30 is not received within a predetermined time and retransmits the data unit when the determination is made. When a determination section 16 determines that a spurious timeout has occurred, a window control section 17 sets a target value for decreasing the size of a congestion window and then gradually decreases the size of the congestion window to the target value when the acknowledgment response is received. Therefore, in a case of executing a response algorithm for changing a slow start threshold and the congestion window, if a segment loss occurs subsequent to the spurious timeout, an efficient loss recovery is achieved and the throughput is improved.

An embodiment of a system and method that uses inline measurements to probe available bandwidth for a transmission control protocol, and adaptively sets a slow-start threshold according to the available bandwidth. The method includes initializing a congestion window “cwnd,” sending cwnd packets, estimating an available bandwidth for the cwnd packets. The congestion window cwnd is set to a higher number, and the higher number of further packets is sent if the available bandwidth is greater than a first threshold level. The available bandwidth is re-estimated for the higher number of the further packets, and a soft start threshold “ssthresh” is set to the re-estimated available bandwidth. A statistical measure is calculated for the re-estimated available bandwidth, and the congestion window cwnd is set equal to ssthresh if a ratio of the statistical measure to the re-estimated available bandwidth is less than a second threshold level.

A plurality of network characteristics of a wireless network are determined and a plurality of TCP session parameters are updated. The network characteristics may be determined based at least in part on a comparison of the estimated bandwidth and estimated propagation delay of the wireless network and the typical bandwidths and propagation delays of one or more wireless networks. The TCP session parameters may be updated based at least in part on the network characteristics. The TCP session parameters may be used to limit the congestion window, retransmission timeout and slow start threshold.

Some embodiments provide a forwarding element that inspects the size of each of several packets in a data flow to determine whether the data flow is an elephant flow. The forwarding element inspects the size because, in order for the packet to be of a certain size, the data flow had to already have gone through a slow start in which smaller packets are transferred and by definition be an elephant flow. When the forwarding element receives a packet in a data flow, the forwarding element identifies the size of the packet. The forwarding element then determines if the size of the packet is greater than a threshold size. If the size is greater, the forwarding element specifies that the packet's data flow is an elephant flow.

A transport layer protocol such as the Stream Control Transmission Protocol uses a new traffic control technique instead of the TCP slow start algorithm. The procedure assumes that the network on which it is implemented has a fixed bandwidth assigned for the connection, and that the allotted bandwidth roughly matches the traffic load. Based on this, under message loss conditions it is only necessary to ensure that signaling traffic emitted into the network by the sender is no greater than the fixed bandwidth that has been allocated to the connection. That is, retransmissions take bandwidth away from a fixed allocation that has been made for the connection, but do not cause the connection itself to reduce the overall traffic it generates into the network; rather, it maintains the same traffic level. This technique prevents congestion in the network from increasing when message loss occurs; at the same time it does not reduce bandwidth for the association as rapidly as the slow start procedure.

The invention discloses a direct current power supply slow starting circuit of a gateway device, and belongs to a power supply control circuit. The direct current power supply slow starting circuit comprises an anti-shake module and a conduction control tube. The anti-shake module is connected with a power adapter and the conduction control tube respectively, and the conduction control tube is connected with the gateway device and is a PMOS tube. The anti-shake module is connected with the grid electrode and the source electrode of the PMOS tube respectively, and the drain electrode of the PMOS tube is connected with the gateway device. The anti-shake module comprises a first resistor, a second resistor, a first capacitor and a second capacitor. A first divider resistor, the first capacitor and the second capacitor are connected in parallel, one end of a parallel end is connected with the power adapter and the source electrode of the PMOS tube respectively, and the other end of the parallel end is connected with the ground through a second divider resistor. The direct current power supply slow starting circuit has the advantages that the circuit is constructed by discrete passive devices, cost is low, the circuit can be restored and acted many times, delay protection time is more effective, and the circuit can bear larger instant impact currents which are loaded by the household gateway device.

The congestion in a network can be avoided by effectively utilizing a prepared network band even in a network where reception intervals of acknowledgments are not correct. According to the information about Ack or Sack (selective acknowledgment) received in a time of the minimum value of an RTT (rtt_min), the number of bytes of received segments (rcv_bytes) for which a receiving side acknowledges the reception is counted, and a received byte number setting unit 16 sets a congestion window (CWND) or a slow start threshold (SSTHRESH) when a packet loss occurs according to the number of bytes of received segments (rcv_bytes) counted by a received byte number counting unit 14 when a packet loss is detected by a loss detection unit 15.

Systems and methods provide for controlling contention in a wireless network device. The systems and methods transmit a packet on a wireless network. If the transmission is not successful, then a contention window parameter is adjusted according to a fast backoff operation. If the packet transmission was successful and the current value of the contention window parameter is less than a threshold value then the contention window parameter is decreased according to a contention avoidance operation. If the packet transmission is successful and the current value of the contention window parameter is greater than the threshold value then the contention window parameter is decreased according to a slow start operation.

An inventive inverter has a semiconductor switch circuit connected to the primary winding of a transformer. The semiconductor switch circuit is respectively controlled by PWM to supply a constant current to the load connected to a secondary winding of the transformer. The inverter is capable of deliberately regulating its ac power output to the load and lowering the lower limit of the output power through control of the intermittent operation, in which an error signal for carrying out the PWM control is reduced to zero during each off-duty period. In addition, the error signal for the PWM control is slowly decreased or increased in each shift from an off-duty period to on-duty period, and vise versa, by charging or discharging the capacitor in a feedback circuit, thereby allowing slow start or slow end of the respective on-off operations for the constant current control through the PWM.

In the preferred embodiments, it is first determined whether or not a TCP connection from a sending device to a receiving device in the wireless communications network is in a slow start phase. If the TCP connection is in a slow start phase, then the data to be sent in the TCP connection that is allocated a priority that is higher than the priority allocated to other data to be sent by the sending device. The sending device may be a mobile terminal, a Serving GPRS Support Node (SGSN), a device in a WiMAX environment or other network device, and the method of the preferred embodiments may be implemented by software installed and executed on the network device.

The invention provides an electronic circuit breaker and a processing method thereof. The electronic circuit breaker and the processing method thereof realize delayed start and overcurrent protection functions by hardware circuits like a current sampling unit, a current limiting control unit, a slow start unit, a current comparing unit, a voltage sampling unit, a driving unit, an electronic switch and the like, so that various instability and delay problems caused by using a microprocessor for overcurrent protection can be avoided.