Abstract: An optical access system capable of avoiding cutoffs or interruption in the periodically transmitted signals that occur during the ranging time is provided. A first method to avoid signal cutoffs is to stop periodic transmit signals at the transmitter during the ranging period, and transmit all the periodic transmit signals together when the ranging ends, and buffer the signals at the receiver to prepare for ranging. A second method is to fix definite periods ahead of time for performing ranging, then cluster the multiple periodic transmit signals together in sets at the transmitter and send them, and then disassemble those sets back into signals at the receiver. The transmitting and receiving is then controlled so that the transmit periods do not overlap with the ranging periods. In this way an optical access system is provided that can send and receive signals requiring periodic transmissions without interruption even during ranging operation.

Abstract: A passive optical network (PON) system which enables plural types of ONUs having different signal transmission speeds to be connected to one OLT. An optical line terminating apparatus (OLT) connected to plural types of ONUs having different signal transmission speeds through an optical distribution network includes an optical transmitter-receiver connected to the optical distribution network, a transmission/reception line interface connected to a wide area network, a downstream frame processing section for converting a packet received by the transmission/reception line interface from the wide area network into a downstream frame containing identification information on a destination ONU in a header, and a downstream transmission controller for modulating the downstream frame at a speed corresponding to a signal transmission speed of the destination ONU and outputting the modulated frame to an electrical/optical converter connected to the optical transmitter-receiver.

Abstract: An optical access communication apparatus and an optical access communication system for the coexistence of two wideband PON systems without using an expensive optical device or module. A low-speed PON and a high-speed PON have a same upstream wavelength, and an OLT receives optical signals by a same optical receiver in the two systems, converts the optical signals into electric signals, amplifies the electric signals, branches the amplified electric signals, and processes the branched signals by clock and data recovery sections of bit rates corresponding to the two PON systems, thereby achieving an optical communication apparatus and an optical communication system for constructing a simple and low-cost triple-play service system of excellent transmission quality.

Abstract: A transmission device uses transmission delay time of reciprocation with the terminal and time information of the transmission device to create a correction value of time information of the terminal and transmits it to the terminal. The terminal includes expected arrival time information based on the time information of the terminal and the correction value received from the transmission device in a frame transmitted to the transmission device. The transmission device compares reception time of the frame with the expected arrival time information in the frame. If they match, the time information of the terminal synchronizes with the time information of the transmission device. If they do not match, the transmission device transmits a new correction value to the terminal. The terminal transmits a frame including expected arrival time information using the new correction value to the transmission device.

Abstract: In a PON system, an OLT periodically transmits a channel resource information block specifying a carrier wavelength and a spreading code on a first downstream channel to which a spread-spectrum spreader having a first spreading code is applied; one of ONUs receives the channel resource information block with a spread-spectrum despreader having the first spreading code and transmits a connection request to the OLT, using the carrier wavelength and the spreading code specified by the channel resource information block; the OLT having received the connection request transmits a new channel resource information block specifying a carrier wavelength and a spreading code to be used on an upstream data channel to the requester ONU through the first channel; and the requester ONU transmits data, using the carrier wavelength and the spreading code specified by the new channel resource information block.

Abstract: An optical access system capable of avoiding cutoffs or interruption in the periodically transmitted signals that occur during the ranging time is provided. A first method to avoid signal cutoffs is to stop periodic transmit signals at the transmitter during the ranging period, and transmit all the periodic transmit signals together when the ranging ends, and buffer the signals at the receiver to prepare for ranging. A second method is to fix definite periods ahead of time for performing ranging, then cluster the multiple periodic transmit signals together in sets at the transmitter and send them, and then disassemble those sets back into signals at the receiver. The transmitting and receiving is then controlled so that the transmit periods do not overlap with the ranging periods. In this way an optical access system is provided that can send and receive signals requiring periodic transmissions without interruption even during ranging operation.

Abstract: An optical access system capable of avoiding cutoffs or interruption in the periodically transmitted signals that occur during the ranging time is provided. A first method to avoid signal cutoffs is to stop periodic transmit signals at the transmitter during the ranging period, and transmit all the periodic transmit signals together when the ranging ends, and buffer the signals at the receiver to prepare for ranging. A second method is to fix definite periods ahead of time for performing ranging, then cluster the multiple periodic transmit signals together in sets at the transmitter and send them, and then disassemble those sets back into signals at the receiver. The transmitting and receiving is then controlled so that the transmit periods do not overlap with the ranging periods. In this way an optical access system is provided that can send and receive signals requiring periodic transmissions without interruption even during ranging operation.

Abstract: A secure storage system for securely accessing a storage device on a network and improving volume management scalability, consisting of a client having a VPN capability; a storage device in an SAN; a management apparatus having a means for managing a storage capacity and a logical volume allocated to the storage device; a converter for converting a protocol used in the SAN to a protocol used in a LAN/MAN/WAN and vice versa; and a conversion apparatus having the VPN capability. A VPN is provided between the client and the conversion apparatus. The conversion apparatus is provided with a mapping between the VPN and an access range of the storage device. A VPN-ID is used for identifying the VPN. An address in the logical volume is used for the access range of the storage device.

Abstract: Provided is an ONU that suppresses transmission of a useless multicast control message to a PON section and enables a communication bandwidth of the PON section to be effectively used. The ONU of the PON system has a multicast group management table that shows a correspondence between a multicast group identifier and an address of a user terminal participating in a multicast group. When the ONU receives a request message of participation in the multicast group from the user terminal, the ONU registers the correspondence between the multicast group identifier indicated by the received message and the user terminal address. A new received message is deleted without being sent to the OLT if another user terminal address is registered already, along with a correspondence with the same multicast group identifier, in the multicast group management table.

Abstract: The invention realizes defect indication on a multipoint logical path and switching of the logical path when the multipoint logical path is configured using a transfer protocol of configuring a logical path, typified by MPLS etc., in a ring network. Two routes of the multipoint logical paths, a working path and a backup path, are set up. Each of them not only transmits a frame transmitted from a transmitting end node to multicast receiving end nodes but also forwards the frame to the transmitting end node and terminates it also at the transmitting end node after making it go around the ring. Any node that detects a defect transmits a forward defect indication frame to a multipoint logical path in which the defect occurs. The transmitting end node having received the forward defect indication frame halts the use of the notified multipoint logical path, and transmits a frame in another path in which the forward defect indication frame is not received within a fixed time period.

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: An object of the present invention is to provide a method of manufacturing a hybrid integrated circuit device, in which multiple circuit boards are manufactured from one large metal board by dicing. The hybrid integrated circuit device of the present invention includes a circuit board with a surface provided with an insulating layer, and conductive patterns provided on the insulating layer. Circuit elements are electrically connected to the conductive patterns. Further, each side surface of the circuit board includes a first inclined portion extending obliquely downward from a peripheral portion of the surface of the circuit board, and a second inclined portion extending obliquely upward from a back surface of the circuit board and formed to be larger than the first inclined portion.

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: In preferred embodiments, a method of manufacturing a hybrid integrated circuit device is provided, in which a plurality of circuit substrates 10 are manufactured from a single metal substrate 10A? by dicing. In some embodiments, the method includes: preparing a metal substrate 10A? having an insulating layer 11 formed on the top surface thereof; forming a plurality of conductive patterns 12 on the top surface of insulating layer 11; forming grooves 20 in lattice form on the rear surface of metal substrate 10B?; mounting hybrid integrated circuits onto conductive patterns 12; and separating individual circuit substrates 10 with, for example, a rotatable cutter.

Abstract: An object of the present invention is to provide a method of manufacturing a hybrid integrated circuit device, in which multiple circuit boards are manufactured from one large metal board by dicing. The hybrid integrated circuit device of the present invention includes a circuit board with a surface provided with an insulating layer, and conductive patterns provided on the insulating layer. Circuit elements are electrically connected to the conductive patterns. Further, each side surface of the circuit board includes a first inclined portion extending obliquely downward from a peripheral portion of the surface of the circuit board, and a second inclined portion extending obliquely upward from a back surface of the circuit board and formed to be larger than the first inclined portion.

Abstract: A transmission apparatus for use in fixed bandwidth communications and variable bandwidth communications. The transmission apparatus has a memory unit, which stores information contained in a frame and indicating the amount of data to be transmitted from a terminal device, a computing unit, which calculates a bandwidth amount to be assigned to the terminal device based on the data amount, and a transmission unit, which sends the calculated assigned bandwidth amount to the terminal device. The transmission apparatus is characterized in that the computing unit calculates bandwidth amounts to be assigned to different types of flow of which different transmission qualities are requested according to a priority level that is set to each flow type. The transmission apparatus is also characterized in that bandwidth is controlled by designating, instead of a necessary bandwidth amount, transmission starting timing and transmission ending timing, particularly for fixed bandwidth communication data.

Abstract: An interconnection between fully synchronous networks of the prior art and next generation frame communications networks, which is required for the shift to next-generation packet networks and a broader-based connection service, is realized. Here, the first point is that a means of bidirectional frame format conversion between a synchronous multiplexing system and a logical multiplexing system is provided, and a method of transmitting data between different networks on a path as if it was being transmitted in the same network. The second point is that 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: An optical access system capable of avoiding cutoffs or interruption in the periodically transmitted signals that occur during the ranging time is provided. A first method to avoid signal cutoffs is to stop periodic transmit signals at the transmitter during the ranging period, and transmit all the periodic transmit signals together when the ranging ends, and buffer the signals at the receiver to prepare for ranging. A second method is to fix definite periods ahead of time for performing ranging, then cluster the multiple periodic transmit signals together in sets at the transmitter and send them, and then disassemble those sets back into signals at the receiver. The transmitting and receiving is then controlled so that the transmit periods do not overlap with the ranging periods. In this way an optical access system is provided that can send and receive signals requiring periodic transmissions without interruption even during ranging operation.

Abstract: A packet forwarding apparatus and network system for providing different types of bandwidth control services to the user; in which a packet forwarding apparatus for transferring data comprises an interface unit for sending and receiving packets, and a traffic shaper for controlling the packet transmission timing and a packet switch for sending an output to the interface unit as the destination of the received packet; and the traffic shaper uses a token bucket algorithm when transmitting a packet to guarantee the minimum frame rate, and uses a leaky bucket algorithm when limiting the peak frame rate.

Abstract: In a network for forwarding user packets by a tunneling protocol, an egress edge node to which tunnels concentrate from a plurality of ingress edge nodes allocates a bandwidth to each of sessions multiplexed through each of the tunnels and notifies each of the ingress edge nodes of the allocated bandwidth, and the ingress node notifies private routers or terminal devices of the allocated bandwidth.