Abstract: Disclosed is a controller-based fault management apparatus and method. The method according to an embodiment of the present disclosure may include: receiving information on a reason of a fault occurring in a network, generating restoration basis information on the fault on the basis of the information on the fault reason; determining whether or not to report a management system of the fault on the basis of the restoration basis information and filtering information, and generating subject to be reported classification information on whether or not the fault corresponds to a subject to be reported to the management system; and when the fault is determined to correspond to the subject to be reported on the basis of the subject to be reported classification information, transmitting information on a fault reason to the management system subject to be reported classification information.

Abstract: A method for providing a protection switching service in a virtual tenant network (VTN) and a controller are provided. The method enables a real-time protection switching setup on a VTN path in order to provide reliability of a VTN service.

Abstract: Provided is a method and an apparatus for protecting a software defined network (SDN), the apparatus including a controller configured to perform a protection switching on at least one working path in an SDN, and a processor configured to set a first event of performing the protection switching and set a protection path before the first event occurs.

Abstract: A method for providing a protection switching service in a virtual tenant network (VTN) and a controller are provided. The method enables a real-time protection switching setup on a VTN path in order to provide reliability of a VTN service.

Abstract: A software-defined networking (SDN) method. The SDN method according to an exemplary embodiment may be used in managing and operating SDN-based network resources in an optical communications network, a fixed mobile convergence subscriber network, a wired broadband subscriber network, a distributed mobile communications base station network, etc.

Abstract: Provided are a method and an apparatus for performing network failure restoration when a failure occurs in a software-defined networking (SDN) network, the method including detecting a failure by verifying whether a failure occurs in a channel and switching a channel from a first channel to a second channel when a failure occurs and thus, recovering from the failure by switching the channel from the first channel to the second channel.

Abstract: An OpenFlow switch which processes a packet received from the outside is provided. The OpenFlow switch includes: a first table used to process a received packet; a second table used to create the first table; and a packet processor that manages the first table and the second table and controls the processing of the packet.

Abstract: There are provided a packet processing apparatus and method for enabling an interface server connected to an external interface to set up a list of multi-layered protocols for processing a received packet and to control all service servers to distributively process the loads of the multi-layered protocols. The packet processing apparatus includes: an interface server configured to set up, if a packet is received from an external node, an execution order of protocols with respect to the received packet, and to edit the packet such that the packet includes information about the execution order of the protocols; a plurality of service servers configured to process the packet according to the corresponding protocols in the execution order of the protocols; and a switch configured to transfer the packet between the interface server and the plurality of service servers.

Abstract: A burst mode optical repeater is provided. The burst mode optical repeater receives optical signals, which are transmitted from a plurality of optical network units (ONUs) in a passive optical network (PON) to a central office using a time division multiplexing access (TDMA) method, and relays the received optical signals using an optical-electrical-optical (OEO) method. Since the burst mode optical repeater can be installed anywhere between an optical line terminal (OLT) and the ONUs, the number of subscribers and transmission range that can be supported by a corresponding network can be increased.

Abstract: Provided are an apparatus and method for efficiently and dynamically allocating a bandwidth on a Time Division Multiple Access-based Passive Optical Network (TDMA PON).

Abstract: According to a method of reducing power in an optical access network, upon the application of power, an optical network terminal (ONT) operates normally in an activation mode. The ONT then determines whether the requirements for switching from activation mode to power-saving mode are satisfied. If the requirements are satisfied, the ONT transmits a sleep signal to an optical line terminal (OLT), which is a message notifying that the ONT will soon switch to power-saving mode. Thereafter, the ONT switches to power-saving mode and cuts off power for all functions except for power for monitoring and controlling external inputs. The ONT then determines whether the requirements for switching from power-saving mode to activation mode are satisfied. If the requirements are satisfied, the ONT transmits a wake-up signal to the OLT and switches to the activation mode for normal operation.

Abstract: Disclosed are an optical line terminal in a gigabit passive optical network and a method for transmitting a broadcast frame using the same. The optical line terminal allocates second port identifiers to optical network units such that a broadcast frame is prevented from being retransmitted to an optical network unit which has transmitted the broadcast frame to the optical line terminal.

Abstract: A passive optical network system includes: a plurality of optical signal splitter receiving optical signals from a plurality of optical network units (ONUs) to provide a plurality of upstream optical signals having different wavelengths; a hybrid optical filter multiplexing the plurality of upstream optical signals in a wavelength division multiplexing (WDM) scheme; and an optical line terminal (OLT) receiving the multiplexed upstream optical signals in a time division multiplexing (TDM) scheme. Therefore, the network system can be easily expanded when the number of subscribers increases, and the optical loss can be minimized.

Abstract: Provided is an automatic optical power control method for an optical line terminal (OLT) of a passive optical network (PON). The automatic optical power control method includes at the OLT, measuring an allowable range of the optical power allowing a normal network operation on the PON, at the OLT, setting an optimum optical signal level within the measured allowable range of the optical power, and at the OLT, adjusting a power level of a transmitter to the set optimum optical signal level. Accordingly, an appropriate power level can be selected depending on an optical distribution network (ODN) structure to drive the transmitter. Also, when the entire optical network units are deactivated, a laser of the transmitter is turned off to thereby minimize unnecessary power consumption at the OLT.

Abstract: Provided are an optical output power control method that provides optical communication without harming the human body even when a transmission line is cut or no optical network unit (ONU) accesses a communication system, and a passive optical network (PON) system using the method. In the method, an optical signal having a predetermined period is transmitted when an optical communication system is in an abnormal state, wherein the predetermined period includes a laser-on time interval in which the optical signal has a normal power level and a laser-off time interval in which the optical signal is off or has a power level lower than the normal power level, so that the optical communication system performs optical communication without harming the human body even during the abnormal state.

Abstract: A dynamic bandwidth allocation (DBA) device and a method thereof are provided. In the DBA method, the band allocation periods according to class queues and allocable bands with respect to each class queue are calculated on the basis of the service level agreement information and stored according to the service types in separate tables. The bandwidth allocation amount is calculated with respect to class queues which have the allocation periods by concurrently checking all the tables at each frame. The upward bandwidth usage efficiency is improved by calculating the final bandwidth allocation information from the service with a high priority order on the basis of the total allocable bandwidth of the corresponding frame. The upward bandwidth allocation amount can be calculated at each frame by reducing the processing speed in calculating the bandwidth allocation amount of each class queue. Accordingly, it is possible to effectively use the network.

Abstract: A time division multiplex (TDM)/wavelength division multiple access (WDMA) passive optical network (PON) device includes a base station terminal, a wavelength splitter, and a subscriber terminal optical transceiver. The base station terminal includes a transmitter, an optical circulator transmitting the optical signals output from the transmitter to an optical distribution network, and a receiver demultiplexing wavelength division multiplexed upstream signals from the optical distribution network through the optical circulator. The wavelength splitter splits the downstream signals from the base station terminal to subscriber ports corresponding to wavelengths and multiplexes the optical signals received from each of the subscriber ports to the base station terminal. The subscriber terminal optical transceiver receives the downstream signals from the wavelength splitter and reuses the received downstream signals as optical sources for upstream signals.

Abstract: Provided is a TDMA (time division multiple access) PON (passive optical network) OLT (optical line terminal) system for a broadcast service, including packet processor determining information according to types of frames (unicast, multicast, and broadcast frames) and a switch output port using header information (an IP address of a packet header, MAC (medium access control) addresses of Ethernet frames, and the like) of data received from an external node or the ONT (optical network terminal) and attaching the information to header parts of the frames to generate second data, a switch copying the second data by a predetermined number of times according to a transmission method and transmitting the second data to a corresponding destination output port according to the identification codes, M TDMA PON MAC processors removing the identification codes added to the second data and converting the second data into TDMA PON frames, and M optical transceivers converting the TDMA PON frames into optical signals and tr

Abstract: An Optical Line Terminal (OLT) configuring a Passive Optical Network (PON) is provided. The OLT includes an optical transmitter that transmits an optical signal to Optical Network Units (ONUs) in a downstream direction, an optical receiver that includes general Continuous Mode (CM) signal processing elements to recover clocks and data from optical signals transmitted by ONUs in an upstream direction, and a controller that controls the ONUs such that the optical receiver continuously receives an optical signal. An OLT interface for receiving an optical signal can be implemented using the general CM signal processing elements.

Abstract: Disclosed are a multiple passive optical network system and a wavelength splitter/combiner used in the same. The multiple passive optical network (PON) system includes a first PON, and a second PON which provides a service different in speed and capacity from the first PON while partially sharing network resources with the first PON. Thereby a subscriber can receive service through a network having a desired capacity and speed.