Abstract: Provided is a packet transmission apparatus including at least one user network interface (UNI) line card configured to receive traffic including a client signal, a fabric switch configured to perform switching on the traffic based on a unit of line card, a network-to-network interface working (NNI-W) line card configured to generate a multiprotocol label switching-transport profile (MPLS-TP) working tunnel to transmit the traffic transferred through the fabric switch, and a network-to-network interface protection (NNI-P) line card configured to generate a MPLS-TP protection tunnel to transmit the traffic transferred through the fabric switch when a fault occurs on a path of the NNI-W line card.

Abstract: A communication terminal performing protection switching in a shared mesh network is provided. The communication terminal configured to transmit and receive data traffic associated with a first working path may include a processor configured to encode, in an optical channel data unit (ODU) including the data traffic, a first operation command message to be received from a first end node, and a communicator configured to transmit the ODU to a neighboring node, in which the first end node is present in a second working path.

Abstract: Provided is an operation method of a node, the method including recognizing multiple failures occurring in a protected domain, transmitting a message including failure information, multiple-failure information, and used path information to a second node when the multiple failures are recognized, and performing a protection switching to a used path determined based on a priority for each of the multiple failures.

Abstract: In a network in which a plurality of protection paths have been formed for one working path between a first node and a second node, each node determines preference levels corresponding to an order to be preferentially used when performing protection switching on the plurality of protection paths. Next, each node exchanges pieces of information about the preference levels determined for the plurality of protection paths.

Abstract: Provided is a failure recovery method in a non-revertive mode of an Ethernet ring network. In an Ethernet ring network, link priorities between nodes or node priorities are determined based on media access control (MAC) addresses and the nodes having blocked ports are determined after failures are recovered from based on the priorities so that the blocked ports can be distributed.

Abstract: A protection switching method and apparatus based on a memory control in a packet transport system are provided. The protection switching method may perform hardware-based protection switching based on a type of path failures that occur. The protection switching method may perform protection switching for each of an Automatic Protection Switching (APS) frame or a Loss of Continuity (LoC)/Clear Loss of Continuity (CLoC) message received via an interface unit from a packet processor, a LoC/CLoC message received via a local bus interface from a host processor, an APS frame generation command input via the local bus interface from protection software (SW) of the host processor, and an APS frame generation command input via another interface unit from the protection SW.

Abstract: An apparatus of determining blocking in an Ethernet ring network sets blocking with respect to each of the plurality of links in an Ethernet ring network, and determines one of the plurality of links as a link to be blocked by using traffic request amounts of a plurality of service flows with respect to the respective links set to be blocked.

Abstract: A method for protection switching in a shared node where protection resources of a plurality of end-to-end linear protection domain are shared is provided. The shared node receives a first protection switching event message notifying that a protection switching event occurs from a first node of a first end-to-end linear protection domain, and determines whether to prohibit protection switching on a second end-to-end linear protection domain by comparing a priority of the first end-to-end linear protection domain with a priority of the second end-to-end linear protection domain.

Abstract: Provided is a linear protection switching method of a node, wherein the method includes selecting a local request based on a priority of at least one local request, determining a global request based on a priority between the selected local request and a remote message, and performing a state transition based on the global request.

Abstract: Provided is a protection end node located at an end of a protection path, wherein the protection end node includes a receiver to receive, from a working end node located at an end of a working path, path defect information indicating whether a defect occurs on the working path, a processor to perform protection switching in response to reception of the path defect information and generate path control information used for the working end node to control a connection of the working path based on the protection switching, and a transmitter to transmit the path control information to the working end node.

Abstract: A method of performing protection switching in a network including a first node and a plurality of second nodes that are connected to the first node is provided. The first node counts the number of obstacles that have occurred in a plurality of paths that are connected between the plurality of second nodes, and if the counted number is smaller than a predetermined threshold value, the first node performs protection switching per leaf. Alternatively, if the counted number is equal to or larger than a predetermined threshold value, the first node performs protection switching per tree.

Abstract: A protection switching unit and a method of performing protection switching of the protection switching unit are provided. The method includes steps of detecting a fault that has occurred at a working path of a network; opening a first switch that is connected to the working path and closing a second switch that is connected to the protection path of the network; and maintaining a connection state of the first switch and the working path and a connection state of the second switch and the protection path, when a fault that has occurred at the working path is restored.

Abstract: A method of operating a root node in which the root node transmits/receives traffic with a plurality of leaf nodes through a plurality of working paths is disclosed, the method including receiving, from a first leaf node, a first signal failure (SF) message indicating an occurrence of a failure on a first working path of the first leaf node, receiving traffic from the first leaf node by switching the first working path to a first protection path, and receiving traffic from remaining leaf nodes aside from the first leaf node while maintaining the working path.

Abstract: A method of operating a root node in a multipoint-connection with a plurality of leaf nodes, the method including transmitting/receiving traffic with the plurality of leaf nodes via a working path, receiving, from a leaf node, a message indicating an occurrence of a failure on a path of the leaf node from among the plurality of leaf nodes, recognizing an occurrence of a local failure on the path connected to the leaf node, and transmitting information about the failure to the leaf node.

Abstract: A method of performing shared mesh protection switching in which congestion does not occur in a sharing segment and that quickly performs linear protection switching while using a 1-phase automatic protection switching protocol is provided. For protection switching of a working path that is included in a end-to-end linear protection domain having a high priority, because of congestion that may occur in a pre-emption process of stopping use of a shared protection segment of a working path that is included in a end-to-end linear protection domain having a low priority, a signal failure occurs at a protection path, and thus operation of a shared mesh protection switching protocol abnormally can be prevented.

Abstract: Provided is a failure recovery method in a non-revertive mode of an Ethernet ring network. In an Ethernet ring network, link priorities between nodes or node priorities are determined based on media access control (MAC) addresses and the nodes having blocked ports are determined after failures are recovered from based on the priorities so that the blocked ports can be distributed.

Abstract: In a multi-domain network in which at least one working interconnected node and at least one protection interconnected node are formed between a first service end node and a second service end node, when a failure has occurred in both a working transport entity and a first protection transport entity of a node, a node having recognized a failure performs switching to a second protection transport entity that is connected to a corresponding interconnected node.

Abstract: Provided is a failure recovery method in a non-revertive mode of an Ethernet ring network. In an Ethernet ring network, link priorities between nodes or node priorities are determined based on media access control (MAC) addresses and the nodes having blocked ports are determined after failures are recovered from based on the priorities so that the blocked ports can be distributed.

Abstract: In a wireless optical communication system in which communication is performed based on a free space and a plurality of the communication apparatuses are arranged in a ring form around a central office terminal (COT), the communication apparatus monitors optical signals received in a first direction or in a second direction opposite to the first direction, and selects a first path through which the optical signals in the first direction are received and a second path through which the optical signals in the second direction are received. The communication apparatus converts an optical signal having a predetermined unique wavelength from among the optical signals received through the selected path into a signal of a frequency domain having a plurality of subcarriers, and obtains packet data mapped to each of the subcarriers.

Abstract: In a network in which a plurality of protection paths have been formed for one working path between a first node and a second node, each node determines preference levels corresponding to an order to be preferentially used when performing protection switching on the plurality of protection paths. Next, each node exchanges pieces of information about the preference levels determined for the plurality of protection paths.