Abstract: Disclosed are a flow control apparatus and method. An apparatus for performing flow control in a software defined network (SDN) environment according to an exemplary embodiment includes a message receiving unit configured to receive a first packet processing inquiry message including a packet from a first switch and a control unit configured to determine whether there is a second proxy connected with a second switch and matching a first proxy connected with the first switch in response to the first packet processing inquiry message, instruct the first switch to transmit the packet such that the packet passes through the first proxy when it is determined that there is a second proxy, and instruct the first switch to transmit the packet such that the packet bypasses the first proxy when it is determined that there is no second proxy.

Abstract: Provided are a terminal and a system and method of measuring a network state using the terminal. The system of measuring the network state according to an embodiment of the present disclosure includes a transmission terminal that transmits exploration packets, and a reception terminal that receives the exploration packets to measure an One-way Trip Time (OTT) of each of the exploration packets and calculates queuing delay using an average value of the measured OTTs and a minimum value of the measured OTTs.

Abstract: Disclosed are a flow control apparatus and method. An apparatus for performing flow control in a software defined network (SDN) environment according to an exemplary embodiment includes a message receiving unit configured to receive a first packet processing inquiry message including a packet from a first switch and a control unit configured to determine whether there is a second proxy connected with a second switch and matching a first proxy connected with the first switch in response to the first packet processing inquiry message, instruct the first switch to transmit the packet such that the packet passes through the first proxy when it is determined that there is a second proxy, and instruct the first switch to transmit the packet such that the packet bypasses the first proxy when it is determined that there is no second proxy.

Abstract: Provided is a method of estimating a queuing delay. The method includes: obtaining a round trip time (RTT) reference value, a forward one-way transmit time (OTT) reference value and a backward OTT reference value; and in accordance with a determination of whether a first increment rate is larger or smaller than a second increment rate, updating one of the forward OTT reference value and the backward OTT reference value based on the RTT reference value, the first increment rate being a rate of increment in local time of the transmitter, the second increment rate being a rate of increment in local time of the receiver.

Abstract: Provided are a data transmission apparatus and a method for the data transmission apparatus to transmit a plurality of packets constituting transmission data to a receiving end. The data transmission apparatus for transmitting a plurality of packets constituting transmission data to a receiving end includes a packet-specific weight calculator configured to calculate packet-specific weights of respective transmission-scheduled original packets at a current time point among the plurality of packets, a packet converter configured to generate one or more error recovery packets from the original packets according to the calculated packet-specific weights, and a transmitter configured to transmit the error recovery packets to the receiving end using a plurality of sessions capable of transmission.

Abstract: Provided is a method of estimating a queuing delay. The method includes: obtaining a round trip time (RTT) reference value, a forward one-way transmit time (OTT) reference value and a backward OTT reference value; and in accordance with a determination of whether a first increment rate is larger or smaller than a second increment rate, updating one of the forward OTT reference value and the backward OTT reference value based on the RTT reference value, the first increment rate being a rate of increment in local time of the transmitter, the second increment rate being a rate of increment in local time of the receiver.

Abstract: Provided are a terminal and a system and method of measuring a network state using the terminal. The system of measuring the network state according to an embodiment of the present disclosure includes a transmission terminal that transmits exploration packets, and a reception terminal that receives the exploration packets to measure an One-way Trip Time (OTT) of each of the exploration packets and calculates queuing delay using an average value of the measured OTTs and a minimum value of the measured OTTs.

Abstract: Provided are a data transmission apparatus and a method for the data transmission apparatus to transmit a plurality of packets constituting transmission data to a receiving end. The data transmission apparatus for transmitting a plurality of packets constituting transmission data to a receiving end includes a packet-specific weight calculator configured to calculate packet-specific weights of respective transmission-scheduled original packets at a current time point among the plurality of packets, a packet converter configured to generate one or more error recovery packets from the original packets according to the calculated packet-specific weights, and a transmitter configured to transmit the error recovery packets to the receiving end using a plurality of sessions capable of transmission.

Abstract: A device authentication method and device authentication apparatus in a multi domain home network environment are provided. The method includes registering a new device in each local domain and issuing a local domain certificate; making an agreement between local domains in order to authenticate a device registered to another local domain; when the device registered to the home local domain or another local domain requests a service, authenticating the device via communication inside the local domains, thereby minimizing a user's intervention, making it easier to use the apparatus, reducing a device operation with regard to a device having limited performance, and making it easier to extend the apparatus.