Abstract: A transmission network is comprised of a network management system for collectively managing and controlling a plurality of transmission devices coupled mutually through transmission routes and the transmission network as well. The network management system includes a plane management table adapted to manage transmission planes defined as a set of paths in the transmission network, and the plane management table has the function to set and manage a transmission plane (working plane) applied during normal operation and besides, a single or a plurality of transmission planes (protection planes) applicable in the event of occurrence of a fault in the transmission network. Then, when a fault occurs in the transmission network, the network management system changes the applied plane to a suitable transmission plane.

Abstract: Disclosed herewith is a packet transfer apparatus that carries out 1+1 protection switching for traffics to be received variably in both length and cycle. The apparatus enables flows to be multiplexed and the link usage efficiency to be improved without generating any buffer overflow errors. The data transfer apparatus, upon receiving the third sequentially numbered data from the first communication route before receiving the preceding second sequentially numbered data, stores the received third data in a buffer. And upon receiving the second sequentially numbered data from the second communication route, the apparatus sends the second and third data sequentially. Then, upon receiving the third sequentially numbered data from the second communication route before receiving the second sequentially numbered data, the apparatus sends the third data when a predetermined waiting time expires.

Abstract: A PON system capable of utilizing the bandwidth of an optical transmission channel in the PON section. In a PON system including an OLT and a plurality of ONUs, the OLT has: a downstream frame processing unit that removes at least part of the header information in a layer 2 header from a downstream frame received from a wide area network, and converts the remaining frame portion into a frame having a header specific to the PON section; and a downstream frame processing unit that extracts a downstream frame portion to be transferred to a user terminal, from a received frame from a PON, and adds the layer 2 header information deleted in the OLT.

Abstract: Provided is a network system including a start device and multiple end devices. A point-to-point (P-to-P) logical path is set to be used for unicast communication between the start device and each of the end devices. A first point-to-multipoint (P-to-M) logical path and a second P-to-M logical path are set to be used for multicast communication from the start device to the multiple end devices. The start device transmits data over the first P-to-M logical path. When one of the end devices detects a defect along the first P-to-M logical path, the end device that has detected the defect transmits a switch request over the P-to-P logical path set between this end device and the start device. The start device receives the switch request and transmits data over the second P-to-M logical path.

Abstract: A clock data recovery circuit that supplies stable reference clocks to the object respectively by shortening the time of bit synchronization with each received burst data signal regardless of jittering components included in the received burst data signal, includes an interpolator that generates a reference clock having the same frequency as that of a received burst data signal and two types of determination clocks having a phase that is different from that of the reference clock respectively; and a phase adjustment control circuit that can change the phase of the reference clock in units of M/2?. After beginning receiving of a burst data signal, the clock data recovery circuit sets a large phase change value at the first phase adjustment timing and reduces the change value in the second and subsequent phase adjustment timings, thereby realizing quick bit synchronization with the received burst data signal to generate a reference clock.

Abstract: Provided is a communication system which is provided with a plurality of communication devices and transfers a packet between the plurality of communication devices through a communication path. When a packet is looped back at any of the communication devices on the communication path to verify connectivity of the communication path, a first communication device of the plurality of communication devices stores, in a first region of header information of the packet, first information for designating the communication device at which the packet is looped back, further stores, in a second region of the header information of the packet, second information on a loopback point in the designated communication device at which the packet is looped back, and sends the packet to which the first information and the second information have been added.

Abstract: An interconnection between fully synchronous networks and next-generation frame communications networks is disclosed. A means of bidirectional frame format conversion between a synchronous multiplexing system and a logical multiplexing system is provided, along with a method of transmitting data between different networks on a path as if it were being transmitted in the same network. Further, when converting network control information in an STM network into data suitable for a packet network, even across the boundary of a synchronous multiplexing system and a logical multiplexing system, a unified communication management means is provided over the whole path.

Abstract: A packet communication apparatus includes a frame buffer of a linked list method and holds chain information and buffer size information, for structuring a linked list buffer for each user flow, in two areas consisting of an operation area and an update area. While usually in service, the buffer is structured by using the chain information in the operation area and the buffer size information in the same area such that the frame is read/written in the frame buffer. When the chain information in the update area and the buffer size information in the same area have been changed, a queue size is changed by reflecting the updated chain information and the updater buffer size information into the operation area, when both the read pointer and the write pointer respectively have gone around the buffer, or when there is no frame stored in the buffer.

Abstract: An interconnection between fully synchronous networks and next-generation frame communications networks is disclosed. A means of bidirectional frame format conversion between a synchronous multiplexing system and a logical multiplexing system is provided, along with a method of transmitting data between different networks on a path as if it were being transmitted in the same network. Further, when converting network control information in an STM network into data suitable for a packet network, even across the boundary of a synchronous multiplexing system and a logical multiplexing system, a unified communication management means is provided over the whole path.

Abstract: The invention realizes defect indication on a multipoint logical path and switching of the logical path using a transfer protocol of configuring a logical path in a ring network. A working path and a backup path are set up where each transmits a frame from a transmitting end node to multicast receiving end nodes, forwards the frame to the transmitting end node and terminates it at the transmitting end node after going around the ring. Any node detecting a defect transmits a forward defect indication frame to a multipoint logical path in which the defect occurs. The transmitting end node receiving the forward defect indication frame halts the use of the notified multipoint logical path, and transmits a frame in another path where the forward defect indication frame is not received. When received from both multipoint logical paths, the transmitting end node copies the frame and forwards them to both paths.

Abstract: A packet communication system of this invention includes a user access device at a user point for providing a user with connectivity to a plurality of carriers, carrier communication networks linked to the user access device, and a carrier management network which controls and manages the user access device and communication devices. A communication device receives a control frame-inserting command from the carrier management network, and sends a control frame containing therein control frame transfer information that indicates which one of termination and send-back processing is performed at a destination device. In response to receipt of the control frame, a user access device that is the destination of this frame extracts therefrom the control frame transfer information. If this information indicates the termination then perform termination; if send-back, add thereto a header necessary for the send-back and then transfer it.

Abstract: A communication device connected to a network includes an input interface that receives a frame; an output frame buffer that holds the frame received by the input interface; multiple bandwidth controllers that controls a read request notice timing of the frame received by the input interface for each flow; an output scheduler that determines a read timing of the frame on the basis of the frame read request of each flow notified by the bandwidth controllers; and an output interface that outputs the frame in the timing notified by the output scheduler, and each of the bandwidth controllers determines on the basis of a token value held by each flow, whether or not the read request of the flow is notified to the output scheduler, and determines the amount of adding or subtracting the token value on the basis of the accumulated number of frames in the output frame buffer.

Abstract: Disclosed herewith is a PON system and a bandwidth controlling method capable of controlling congestion with use of an upstream bandwidth in a PON section efficiently when congestion occurs in a gateway (GW) connected to an OLT. An OLT connected to a plurality of ONUs through a passive optical network (PON) and to a gateway (GW) through a communication line, when receiving a congestion occurrence notice indicating a congestion occurred output number from a GW, identifies the identifier of the ONU that is using a GW output line having the congestion output port number and shifts the bandwidth controlling of the PON section in a normal mode for allocating a bandwidth to each ONU normally to that in a bandwidth suppression mode for allocating a congestion time allowable bandwidth that is less than the current bandwidth to the ONU having the identified ONU identifier and a bandwidth to each of other ONUs according to its transmission queue length.

Abstract: Provided is a multicast path management method for a connectionless communication. Also provided is a path protection function which is effective when a path has failed. A network is formed by a trunk and a branch path. The multicast path is managed by end-to-end and when a failure has occurred, an instruction is issued from the apex of the multicast tree to respective end-to-end paths so as to switch from the currently used channel to a backup path. Thus, upon failure, an individual path protection can be performed without affecting other parts of the tree to which the same multicast flow as the defective path is distributed or the distribution state of the multicast flow.

Abstract: Edge nodes form point-to-point communication paths with one another. Multiple communication paths set at one port of an edge node and/or a relay node are regarded as a group. Identification information of the port and identification information of a group that outputs a frame inputted into the port are previously stored as associated with each other. If the destination address of a frame inputted into the port is unknown, an outgoing interface search unit identifies at least one group corresponding to the port. The frame is outputted from a port corresponding to the identified group.

Abstract: Disclosed is a low melting point glass which has excellent water resistance and can impart excellent flame retardancy to a resin composition. Also disclosed is a resin composition comprising the low melting point glass. Further disclosed is a resin molded article. Specifically disclosed is a low melting point glass which comprises 22-27 mol % of P2O3, 3-18 mol % of SO3, 25-40 mol % of ZnO, 0-2 mol % of Al2O3, 0-4 mol % of Li2O, 0-15 mol % of Na2O and 11-35 mol % of K2O, wherein the total amount of Li2O, Na2O and K2O is 25-35 mol %. The low melting point glass has a glass transition temperature of 200 to 300° C. exclusive. A resin composition is produced by mixing the low melting point glass with a resin. A resin molded article is produced by molding or curing the resin composition.

Abstract: A link aggregation function and maintenance function by MPLS OAM. Identical entry information is stored in plural circuits IF which perform a LA setting. In this way, multiplexing to the same LSP is possible even with different IF. The first network IF is assumed to be OAM ACT, and the second network IF is set to OAM SBY (SBY). OAM frame insertion is performed only by an OAM ACT port. In this way, in an opposite MPLS transmission apparatus, it is possible to prevent CV frame reception above a specified number of frames. Further, a switch forwarding table is set to forward frames from the network side to the first network IF of OAM ACT. The second network IF which was set to OAM SBY does not perform fault detection by CV reception. In this way, incorrect detection of faults due to non-reception of OAM can be prevented.

Abstract: A packet transfer apparatus connects two networks of different protocols. The packet transfer apparatus, connected to a first communication network and a second communication network, performs the steps of: storing first destination correspondence information; receiving a packet of the first communication protocol; based on the first destination correspondence information, determining destination information of a packet of the second communication protocol corresponding to destination information of the received packet of the first communication protocol; generating the header of the packet of the second communication protocol, based on the determined destination information of the packet of the second communication protocol; converting the received one or more packets of the first communication protocol into one or more packets of the third communication protocol; and adding the generated header of the packet of the second communication protocol to the packets of the third communication protocol.