Abstract: A multi-layer data processing apparatus and method. The multi-layer data processing unit may classify received multi-layer data into lower layer data and higher layer data using lower layer information, and generate and output a traffic flow of the lower layer data or traffic flows of the lower layer data and the higher layer data with reference to a rule information table. In the rule information table, pieces of lower layer rule information may be linked to pieces of higher layer rule information.

Abstract: A time stamping apparatus and method for network timing synchronization are provided. A receiving apparatus receives data from a transmitting apparatus, generates a synchronization pulse signal synchronized with a local clock of the transmitting apparatus based on the received data, wherein the received data include information regarding the transmission time of the data, measured using the local clock of the transmitting apparatus, and the receiving apparatus measures the reception time of the data using the synchronization pulse signal. Therefore, accurate network timing synchronization may be achieved.

Abstract: A parallel processing-based time synchronization apparatus is disclosed. The time synchronization apparatus employs a double-filter structure based on parallel processing, thereby providing more precise and reliable time synchronization between a master device and a slave device.

Abstract: A method and apparatus for protection switching in a ring network are provided. A method for protection switching in a ring network, which includes a first ring network having first and second connection nodes and a second ring network connected with the first ring network through the first and second connection nodes, includes: receiving, by the first connection node, first and second R-APS messages transmitted from nodes belonging to the first ring network; determining, by the first connection node, the position of closure in the first ring network by using the first and second R-APS messages and topology information; receiving, by the first connection node, a topology change signal transmitted from the second ring network; and transmitting, by the first connection node, an FDB flush message with reference to the position of closure.

Abstract: Provided are a method and apparatus for dynamically managing hierarchical flows that more efficiently process packet traffic while maintaining compatibility with an existing packet data network in transferring both circuit traffic and packet traffic in a packet switched network. The method for dynamically managing hierarchical flows includes: receiving data packets, classifying the data packets according to attributes of the received data packets, and producing first flows; determining whether traffic of each of the first flows exceeds a predetermined bandwidth limit, and performing a packet drop process or producing second flows for first flows that exceed the bandwidth limit, according to a flow-specific policy; and performing second flow processing on the second flows according to a second flow policy. Only flows exceeding the bandwidth limit or causing congestion are hierarchically divided for management. This makes it possible to finely manage the flows without complex operations.

Abstract: Provided is a hierarchical packet processing apparatus and method. In one general aspect, a packet is analyzed, divided into an upper layer and a lower layer. It is determined whether a property of the packet to be analyzed has been already analyzed or has to be re-analyzed with respect to each of the upper and lower layers of the packet. Therefore, deep packet inspection is performed only when it is required, and thus assurance of quality of service (QoS) during packet processing can be achieved, as well as reduced waste of resources.

Abstract: There is provided a packet transport layer apparatus. The packet transport layer apparatus can receive frames having different formats via a single port by dividing a single physical port into a plurality of virtual ports according to each frame format, can increase the number of customer virtual local area networks (C-VLANs) and the number of service VLANs (S-VLANs) being usable at the same time by assigning a different component identifier (ID) to each frame format and using the component ID as a factor used in searching a filtering table, and can translate a frame format to be suited to a frame format allocated to a virtual output port.

Abstract: Provided is a network flow-based scalable video coding (SVC) adaptation device. Without permitting a network transmitting end to divide image data into image data having various levels of quality and send the image data having the various levels of quality to all networks, since an adaptation device is installed in a network device of an ingress of a lower network of a subscriber and the adaptation device and the network transmitting end share network information about attributes of a terminal and the lower network of the subscriber so as to provide an image service having image quality corresponding to the terminal to the terminal, network efficiency can be maximized.

Abstract: Provided is a method and apparatus for synchronizing a time of day (TOD) in a convergent network, wherein the TOD is received from a time server connected in the convergent network and is provided to a terminal connected in a wired or wireless network, specifically a terminal connected in a heterogeneous network, that requires TOD information. The apparatus includes a time server that provides standard TOD information, a gateway or a host personal computer (PC) that provides the standard TOD information of the time server to the terminal in a 3rd layer or lower instead of an upper layer of the open system interconnection (OSI) 7 layer model, and the terminal that adjusts a local clock according to the provided standard TOD information. According to the method and apparatus, the terminal not only maintains a very precise TOD by obtaining TOD information of the time server periodically or when required, but also obtains the TOD information without using application software for processing the TOD information.

Abstract: A timestamping apparatus for network synchronization includes a recovery unit and a timestamping unit. The recovery unit extracts a recovery clock operating at an operation frequency of a transmission terminal from a sync signal received from the transmission terminal. The timestamping unit measures a timestamp value of an arrival time of the sync signal by measuring a phase difference between the recovery clock and a local clock of a receiving terminal.

Abstract: Provided are a time synchronization method allowing a fixed time delay and a bridge that is interposed between a master and a slave, according to the method. In the bridge, a predetermined time after the synchronization packet is set as an output time of the synchronization packet and the synchronization packet is output at the output time. Accordingly, it is possible to delay synchronization packets in the bridge for the same time, thereby increasing the time synchronization precision.

Abstract: An aggregation switch apparatus for broadband subscribers is disclosed. The apparatus includes: an upstream input buffering unit for buffering packets from more than one subscriber link; a scheduling unit for aggregating the packets to more than one upstream link and scheduling a transfer order; a rate match buffering unit for buffering a transfer rate difference between an output of the upstream input buffering unit and an output of more than one upstream link; a downstream destination identifying unit for identifying a destination of more than one subscriber link of the packets; a broadcasting unit for transferring the packets to terminals of the broadcasting unit; a packet selecting unit for selecting a corresponding packet by identifying a destination port of more than one subscriber link of the packets; and a downstream output buffering unit for buffering the packets outputted from the packet selecting unit to said more than one subscriber link.

Abstract: A system and method for time synchronization on a network is provided. According to the system and method for time synchronization, a slave clock device does not continuously receive a time synchronization message periodically transferred from a master clock device and thus does not correct its time upon all such occasions. Rather, the slave clock device requests time information from the master clock device only when the slave clock device needs to correct its time, and receives a time synchronization message transferred from the master clock device and compensates for its time deviation only while the slave clock device is activated, thereby reducing its power consumption and amount of computation.

Abstract: Provided are a method and apparatus for dynamically managing hierarchical flows that more efficiently process packet traffic while maintaining compatibility with an existing packet data network in transferring both circuit traffic and packet traffic in a packet switched network. The method for dynamically managing hierarchical flows includes: receiving data packets, classifying the data packets according to attributes of the received data packets, and producing first flows; determining whether traffic of each of the first flows exceeds a predetermined bandwidth limit, and performing a packet drop process or producing second flows for first flows that exceed the bandwidth limit, according to a flow-specific policy; and performing second flow processing on the second flows according to a second flow policy. Only flows exceeding the bandwidth limit or causing congestion are hierarchically divided for management. This makes it possible to finely manage the flows without complex operations.

Abstract: Provided are a clock signal selecting apparatus and method that can guarantee the continuity of an output clock signal. The clock signal selecting apparatus and method can synchronize the phases of at least two clock signals by continuously controlling the phases of the clock signals. Accordingly, even when an active clock signal and a standby clock signal have different frequencies, it is possible to guarantee the continuity of the output clock signal regardless of whether the clock signals are switched from one to another. In addition, it is possible to guarantee the stability of the output clock signal.

Abstract: Provided is a dynamic rate-limiting method and apparatus used in a switch for switching packets from input ports to output ports, the method including: (a) adding traffic bandwidth values set in advance in active subscribers that are using the switch from among subscribers connected to the switch; (b) comparing the added value with a range between a maximum bandwidth and a minimum bandwidth that are set in the switch; and (c) according to a result of comparing, when the added values is smaller than the minimum bandwidth or larger than the maximum bandwidth set in the switch, increasing or decreasing the traffic bandwidths of the active subscribers set in advance so that the added value is within the range between the maximum bandwidth and minimum bandwidth. Accordingly, it is possible to automatically control the traffic bandwidths of subscribers that are currently using the switch.

Abstract: A multi-functional switch fabric apparatus and a control method for a multi-functional switch fabric apparatus are provided. The multi-functional switch fabric apparatus includes a plurality of input data processors, which copy, distribute, switch, and output input user data according to a mode set signal from the outside, a switch fabric unit, which includes a plurality of switching units and selectively outputs the user data input from the plurality of input data processors according to the mode set signal, a plurality of output data processors, which buffer, schedule, multiplex, and output the user data input from the switch fabric unit, and a control unit, which outputs the mode set signal to control the plurality of input data processors, the switch fabric unit, and the plurality of output data processors.

Abstract: Provided are a data transceiver and method for performing equalization and pre-emphasis adaptive to the transmission characteristic of a transmitting part. The transceiver measures the signal attenuation characteristic of a transmission line of a receiving part using an input data signal input via the transmission line of the receiving part, decodes the distorted waveform of the input data signal, distorts the waveform of an output data signal beforehand using the measured signal attenuation characteristic of the transmission line of the receiving part, and transmits the output data signal via a transmission line of a transmitting part. Thus, when the output data signal is transmitted via the transmission line of the transmitting part, the waveform of the signal remains optimized.

Abstract: A method of classifying packets by a subscriber and processing classified packet to provide fairness to subscribers is provided. In order to classify the packets by the subscriber, a subscriber identification tag is inserted into a predetermined portion of an Ethernet frame and the packets are classified using the subscriber identification tag. The classified packets are processed based on the classifying result. Accordingly, an intermediate node not directly connected to the subscriber can classify the packets by the subscriber even in an uncontrollably expanded subscriber network. Therefore, the subscriber network is simply and effectively managed while providing the fairness to the subscriber in processing packets and allocating bandwidth.

Abstract: An efficient switching device and a method for fabricating the same using multiple shared memories are provided. The switching device includes: an output time determination unit to determine an output time to an output port; an output time administration unit to administer a possible data output time for each output port; a memory bank selection unit to select a memory bank with an empty data output time position; a memory bank utilization information administration unit to administer utilization information per output time; a connection unit to deliver transmission data to an output time position; a shared memory unit to store the data in the output time position, to administer dispersed shared memory banks according to an output time, and to read and output transmission data; and an output port connection unit receiving output data to read and transmit output port information of the data to a corresponding output port.