Abstract: A method and system for measuring a distance between nodes in a packet network are provided. The system and method include measuring and storing a departure time of a ping packet sent from a source node to a destination node, sending a response packet with respect to the ping packet from the destination node to the source node, cutting through the ping packet or response packet to a successive node or the destination node without an intermediate node delay, computing a round-trip time by measuring an arrival time of the response packet at the source node and measuring the distance between the nodes, based on the round-trip time and speed of the ping packet.

Abstract: Provided is a method of transmitting an Ethernet frame via a network bridge, the method includes receiving a frame header from a previous node connected to the network bridge; receiving a header cyclic redundancy check (CRC) flag and header CRC with respect to the frame header from the previous node; determining whether to forward the Ethernet frame including the frame header by referring to the header CRC flag and the header CRC; and forwarding the Ethernet frame from the previous node to a next node connected to the network bridge according to the determination.

Abstract: A proximity control method for transmitting a content and a network node using the proximity control method is provided. A proximity control method for transmitting a content performs a different proximity control mechanism depending on each of a single proximity control (SPC) domain, a mixed proximity control (MPC) domain, and a network-based service domain, and each of nodes performs the different proximity control mechanism based on a physical distance from a neighboring node, the nodes being comprised in the SPC domain, the MPC domain, and the network-based service domain.

Abstract: Provided is a network synchronization method and apparatus for performing a time synchronization between nodes. When a system starts up and the time synchronization between the nodes is initiated, the network synchronization method and apparatus may enhance jitter, wander, and a time synchronization performance by gradually increasing a window size for a propagation time measurement. When a full window of propagation time measurements is collected, the network synchronization method and apparatus may enhance jitter, wander, and the time synchronization performance by applying an exponential to a computation of an average propagation time value.

Abstract: A network intermediate device and method are provided. The network intermediate device according to an exemplary embodiment of the present invention comprises a data transmitting/receiving part which receives frames which have header error check information, and a control part which controls the data transmitting/receiving part to start forwarding the frame before the entire frame is received by determining whether there are errors in the header using the header error check information. In this case, the frame may comprise a first field in which header error check flag information is recorded to notify whether to perform the forwarding after checking for errors in the header, and a second field in which the header error check information is recorded. If it is confirmed that the check and forward method is applied by the header error check flag information, the control part may verify the header error check information to determine whether errors occur in the header.

Abstract: A system and method for determining a propagation delay between nodes in a packet network are provided. The system and method include sending a ping packet from a source node to a destination node, determining an intermediate node delay of the ping packet at an intermediate node and recording the intermediate node delay in the ping packet and determining the propagation delay at the destination node by using the intermediate node delay.

Abstract: Provided are a network system supporting a spanning tree protocol (STP), a relay apparatus thereof, and a method of creating a spanning tree. Proposed is a method of creating a tree topology, between AVB bridges, using a STP message including a group MAC address which is different from that used in a non-AVB (Audio Video Bridging) bridge (that is, a bridge without the function of AVB), in order to form a minimum number of AVB clouds. Therefore, it is possible to efficiently ensure transmission quality of a multimedia stream such as an AVB stream.

Abstract: A method and system for measuring a distance between nodes in a packet network are provided. The system and method include measuring and storing a departure time of a ping packet sent from a source node to a destination node, sending a response packet with respect to the ping packet from the destination node to the source node, cutting through the ping packet or response packet to a successive node or the destination node without an intermediate node delay, computing a round-trip time by measuring an arrival time of the response packet at the source node and measuring the distance between the nodes, based on the round-trip time and speed of the ping packet.

Abstract: A method and system for measuring a distance between nodes in a packet network are provided. The system and method include measuring and storing a departure time of a ping packet sent from a source node to a destination node, sending a response packet with respect to the ping packet from the destination node to the source node, cutting through the ping packet or response packet to a successive node or the destination node without an intermediate node delay, computing a round-trip time by measuring an arrival time of the response packet at the source node and measuring the distance between the nodes, based on the round-trip time and speed of the ping packet.

Abstract: Provided is a method of transmitting an Ethernet frame via a network bridge, the method includes receiving a frame header from a previous node connected to the network bridge; receiving a header cyclic redundancy check (CRC) flag and header CRC with respect to the frame header from the previous node; determining whether to forward the Ethernet frame including the frame header by referring to the header CRC flag and the header CRC; and forwarding the Ethernet frame from the previous node to a next node connected to the network bridge according to the determination.

Abstract: Provided is a method of transmitting an Ethernet frame via a network bridge, the method includes receiving a frame header from a previous node connected to the network bridge; receiving a header cyclic redundancy check (CRC) flag and header CRC with respect to the frame header from the previous node; determining whether to forward the Ethernet frame including the frame header by referring to the header CRC flag and the header CRC; and forwarding the Ethernet frame from the previous node to a next node connected to the network bridge according to the determination.

Abstract: Provided are a synchronizing apparatus and method for performing synchronization in a packet network. The synchronizing apparatus includes a sampling unit to measure a time difference using a plurality of time stamps included in a plurality of two-way message packets, an estimating unit to estimate a frequency offset by applying a baseline algorithm to the time difference, a verifying unit to verify the frequency offset to remove an error caused by network delay variation, and a synchronizing unit to remove the frequency offset from a local slave clock signal and generate a slave clock signal synchronized to a clock signal of a master device.

Abstract: Provided is a network synchronization method and apparatus for performing a time synchronization between nodes. When a system starts up and the time synchronization between the nodes is initiated, the network synchronization method and apparatus may enhance jitter, wander, and a time synchronization performance by gradually increasing a window size for a propagation time measurement. When a full window of propagation time measurements is collected, the network synchronization method and apparatus may enhance jitter, wander, and the time synchronization performance by applying an exponential to a computation of an average propagation time value.

Abstract: A method, core node, ingress edge node, and egress edge node for matching a bit rate of data input into an optical burst switching network with that of data output from the optical burst switching network are provided. The method includes calculating a difference between a frequency of optical data received on a node and a natural frequency of the node; including the calculated difference into control information; and transmitting the control information. The core node includes a calculator to calculate a difference between frequency of optical data and the natural frequency of the optical data; and a controller to add the difference and a difference included in control information, and output the added difference. The ingress edge node includes a data processor; and a controller. The egress edge node includes an ingress edge node clock recovery phase lock loop; a de-mapper; and a storage unit.

Abstract: Provided are a time synchronizing method and apparatus based on a time stamp. The time synchronizing method includes: transmitting a local time stamp based on a free-running local clock to a master node; receiving a response time stamp from the master node; calculating a delta time value based on the response time stamp; filtering the delta-time using a digital low pass filter running at the free-running local clock rate; and adjusting a local clock time based on the filtered delta time value.

Abstract: Provided are a synchronizing apparatus and method for performing synchronization in a packet network. The synchronizing apparatus includes a sampling unit to measure a time difference using a plurality of time stamps included in a plurality of two-way message packets, an estimating unit to estimate a frequency offset by applying a baseline algorithm to the time difference, a verifying unit to verify the frequency offset to remove an error caused by network delay variation, and a synchronizing unit to remove the frequency offset from a local slave clock signal and generate a slave clock signal synchronized to a clock signal of a master device.

Abstract: An apparatus and method for adjusting a receiving time point of burst data in an optical burst switching network is provided. The method includes comparing a reference time point of a node with a time slot boundary of the burst data; and adjusting the time slot boundary of the burst data in accordance with the reference time point. The apparatus includes a sync detection section which is configured to detect a difference between a time slot boundary of the burst data and a reference time point; and a sync control section which is configured to control shifting and re-aligning the received burst data with the reference time point according to the difference detected by the sync detection section.

Abstract: A time-slotted optical burst switching system and method therefor can support data transmissions for a constant bit rate (CBR) and at a variable bit rate (VBR) and improves a data transmission method at an edge node and a core node. Accordingly, it is possible to perform a data service for the constant bit rate and for a variable bit rate and to substantially prevent a delay due to a scheduling for a slot assignment at the core node by transmitting a burst control packet before the data burst to be transmitted at the edge node is generated in case of transmitting the data burst at the constant bit rate.

Abstract: Provided are a network system supporting a spanning tree protocol (STP), a relay apparatus thereof, and a method of creating a spanning tree. Proposed is a method of creating a tree topology, between AVB bridges, using a STP message including a group MAC address which is different from that used in a non-AVB (Audio Video Bridging) bridge (that is, a bridge without the function of AVB), in order to form a minimum number of AVB clouds. Therefore, it is possible to efficiently ensure transmission quality of a multimedia stream such as an AVB stream.

Abstract: A time synchronization method between nodes in a network and an apparatus for implementing the same, the time synchronization method including: measuring a value of a propagation time from a slave node to a master node using a time stamp for each of one or more predetermined time units; calculating an estimate of an actual propagation time using the one or more measured values and a sliding window; and computing an offset using a message transmission time corresponding to a sending of a message from the master node, a message receipt time corresponding to an arrival of the message at the slave node, and the estimate of the actual propagation time.