Abstract:
PURPOSE: A synchronizer of a packet network and a method thereof are provided to estimate the propagation delay and phase offset efficiently in real time. CONSTITUTION: A synchronizer of a packet network(10) includes a sampling unit(102), an estimating unit(104), and a synchronization unit(106). The sampling unit samples the delay fluctuation of continuous packets. The estimating unit estimates the propagation delay and phase offset from the delay fluctuation samples filtered through a low pass filter and plural filters, in real time. The synchronization unit removes the propagation delay and phase offset estimated from a local slave clock to generate a slave clock synchronized with a master.
Abstract:
본 발명은 확장된 AVB(Audio/Video bridging) 예약 프로토콜을 이용한 AVB 시스템 및 자원 예약 방법에 관한 것이다. 본 발명에 따른 확장된 AVB 예약 프로토콜을 이용한 AVB 시스템은, 어플리케이션 스트림 식별자 또는 AVB 스트림 식별자를 포함하는 GARP(Generic Attribute Registration Protocol) 메시지를 중계 장치로 전송하는 유출(egress) 장치, 상기 GARP 메시지에 따라 상기 AVB 스트림 식별자 또는 상기 어플리케이션 스트림 식별자를 등록하고, 상기 어플리케이션 스트림 식별자를 포함하는 GARP 메시지를 유입(ingress) 장치로 전송하는 중계 장치 및 상기 어플리케이션 스트림 식별자를 포함하는 상기 GARP 메시지를 통해 상기 어플리케이션 스트림 식별자에 대응하는 AVB 스트림 식별자를 할당하고, 상기 중계 장치로 예약 신호를 전송하는 상기 유입 장치를 포함한다. AVB 예약 프로토콜(Audio/Video bridging reservation protocol), RSVP(Resource ReserVation Protocol), GARP(Generic Attribute Registration Protocol), UPnP-AV(Universal Plug and Play-Audio/Video), UPnP-QoS(Universal Plug and Play-Quality of Service)
Abstract:
PURPOSE: A synchronizing apparatus and a method of packet network are provided to remove instant an error due to network delay variation by using verification algorithm. CONSTITUTION: A sampling unit(102) measures a time difference from a time stamp included in a bidirectional message packet. An estimation unit(104) presumes the frequency offset by applying the reference line algorithm to the measured time difference. A verification part(106) verifies a presumed frequency offset to eliminate an error caused by a network delay change. A synchronization block(108) generates a slave clock synchronized to a master by eliminating the verified frequency offset the from the local slave clock. An estimation unit gets a reference line formed as a points corresponding to the message which is not delayed among the measured time difference. The estimation unit presumes the slope of the reference line as a frequency offset value.
Abstract:
A proximity control method for transmitting contents and a node of a network using the same are provided to measure an exact physical distance between neighboring nodes of a home network, and confirm proximity effectiveness between the nodes by using the physical distance. A different proximity control mechanism is performed according to each domain of an SPC(Single Proximity Control domain)(201), an MPC(Mixed Proximity Control domain)(202) and a network based service domain(203). Each source node(205) included in the domain performs the proximity control mechanism based on a physical distance between the node and a neighboring node(206). The source node includes a set-top box for an electronic home appliance connected through a home network(204) or the connection with an external network.
Abstract:
A method for accurately and securely measuring propagation delay and a distance between a sending and a receiving node in a packet network using a cut-through approach and a packet network node for executing the same are provided to reduce delay at a destination of a ping packet and to make it possible to determine propagation delay and a distance between nodes by changing fields of the ping packet and transmitting a response packet of the ping packet to a source node of the ping packet. A method for accurately and securely measuring propagation delay and a distance between a sending and a receiving node in a packet network using a cut-through approach comprises the following several steps. A transmission time of a ping packet to be transmitted from a source node and a destination node is measured and stored(S301). The destination node transmits a response packet of the ping packet to the source node(S303). An intermediate node cuts through the ping packet or the response packet without delay and then transmits the ping packet or the response packet to the next node or the destination node. The source node measures a receipt time of the response packet and calculates a round trip time(S304). A distance between nodes is measured on the basis of the round trip time and a propagation speed of the ping packet(S305).
Abstract:
본 발명은 콘텐츠 전송을 위한 접근 제어 방법 및 상기 접근 제어 방법을 이용하는 네트워크의 노드에 관한 것이다. 본 발명에 따른 단일 접근 제어 도메인(SPC: Single Proximity Control domain), 혼합 접근 제어 도메인(MPC: Mixed Proximity Control domain) 및 네트워크 기반 서비스 도메인의 각각의 도메인에 따라 서로 다른 접근 제어 메커니즘을 수행하고, 상기 도메인에 포함된 각각의 노드는 서로 이웃한 노드와의 물리적 거리에 기초하여 상기 접근 제어 메커니즘을 수행한다. AVB(Audio/Video Bridge), 접근 제어(proximity control), IEEE802, DTCP(Digital Transmission Content Protection), DLNA(Digital Living Network Alliance)