Hitachi, Ltd.

Nec Corporation

Nippon Hoso' Kyokai

Hitachi Electronics, Ltd.

Hitachi Electronics Co., Ltd.

Michio Masuda

Motoo Nishihara

Hiroyasu Ohtsubo

Hiroaki Nabeyama

Hideo Nishijima

Makoto Ogawa

Atsushi Yoshioka

Akio Yanagimachi

Takehiko Yoshino

Teruhiro Takezawa

Masaaki Fukuda

Tatsuo Kayano

Hisakichi Yamane

Eiichi Sawabe

Takashi Uehara

Takuya Imaide

Masaru Noda

Kaneyuki Okamoto

Kenshin Yamada

Yasufumi Yumde

Masataka Sekiya

Hitoaki Owashi

Koichi A Ono

Iwao Aizawa

Kuniaki Miura

Katsuyuki Watanabe

Kentaro Hanma

Tomomitsu Kuroyanagi

Morito Rokuda

Toshiaki Arikawa

Kohji Minabe

Takao Arai

Takaharu Noguchi

Osamu Yamada

Shigeyuki Itoh

Yoshizumi Watatani

Ryuji Nishimura

Toshiyuki Kurita

Shinya Ohba

Morishi Izumita

Fumio Inoue

Masaharu Kobayashi

Yukinobu Tada

Katsuo Mohri

Kurenai Murakami

Toshiro Aizawa

Akihide Okuda

Jun Kobayashi

Fumihiko Yamanushi

Kazunori Kotani

Tetsuo Yamamoto

Takao Aria

A multi-layer class identifying communication apparatus, includes an input interface connected to input communication lines; a switch circuit; and an output interface connected to output communication lines. The input interface comprises an allocating section which determines a class identifier indicative of one of classes to which an IP packet belongs, from header data of the IP packet received through one of the input communication lines, and allocates an IP-QOS (Internet-Protocol-Quality-of-Service) code to the IP packet. The switch circuit selects one of the output communication lines based on a destination address of the IP packet, such that the IP packet is outputted from the output interface to the selected output communication output interface.

Multi-layer class identifying communication apparatus with priority control

A network node of a SONET ring is provided with a tributary line interface that receives packets from LAN users. A packet switch performs a switching operation on the LAN packets. An aggregate line interface establishes an STM path on a communication link and a number of packet paths within the STM path. An STM switch connects the packet switch between the tributary line interface and the aggregate line interface so that the switched packets are transported over the packet paths. Monitoring circuitry monitors the LAN packets and produces a warning signal if an abnormal condition is detected in one of the packet paths and transmits the warning signal to the communication link. Preferably, the monitoring circuitry is provided in the tributary line interface.

Transport network with circuitry for monitoring packet path accommodated in STM path

An optical network with an optical adaptation layer whose order is higher than synchronous optical network (SONET) layer and lower than Internet protocol (IP) layer is provided. The optical adaptation layer is configured to construct an optical adaptation frame into which IP flows are aggregated at an edge node.

Optical adaptation layer frame for aggregating IP flows at edge nodes for sonet transport

In the packet scheduling device, the output class selection part is made to conduct the selective output of priority class, based on the weight count value calculated from a weight value corresponding to minimum guarantee bandwidth for each priority class and the amount of packet accumulated in each queue. The output class selection part operates so that if the weight count value is &ldquo;0&rdquo; or more, then the packet length of variable-length packet data to be output is subtracted from the current weight count value to give a renewed weight count value. On the other hand, if the weight count value is less than &ldquo;0&rdquo;, until reaching a predetermined repeat count (Cmax&minus;1), the weight value of each priority class is added to the weight count value of all priority classes, and, when reaching the repeat count (Cmax&minus;1), the weight value is added to the weight count value of all priority classes or replaced by half the weight value. Thereby, the weight count value is made to be more than &ldquo;0&rdquo;, and the values thus renewed are subject to the rule of round robin so as to select the priority class.

Packet scheduling device

A transfer destination determining apparatus and method performing a load distribution in a network, where a plurality of transfer destination subjects are present as a transfer destination of a datagram, while the same collected flows are transferred to the same transfer destinations, the transfer destinations are allocated with respect to each of the collected flows. This apparatus has an extracting part extracting address and flow discrimination information, in the IP datagram; route solving part determining a transfer path based on the address information. When the determined path is a single path, the transfer destination is uniquely determined and the path is outputted to a post-staged apparatus, whereas when the path is a multi-path having a plurality of transfer destination subjects a multi-path number is outputted to a flow managing means which determines a transfer path corresponding, to a collected flow based on the received flow discrimination information and the multi-path number.

Transfer destination determining process apparatus

A lightwave network data communications system having such an architecture that routing operation within a lightwave network is simplified, and a high-speed transfer process is attained in a large-scale basic network utilizing a wavelength division multiplexing (WDM) technology which accommodates internet traffics from a plurality of subscriber networks. The lightwave network data communications system includes a unit for giving a lightwave router address to an edge router and a core router in the lightwave network, a unit for resolving a destination lightwave router address and an aggregated flow identifier about an IP packet received from a subscriber, and encapsulating the IP packet into a lightwave adaptation frame with these pieces of data contained in header information in the edge router, a unit for encapsulating a plurality of packets each having a length under a fixed length into a superframe, a unit for executing a share-ride scheme in which the packets of a plurality of IP flows can be shared as a superframe, and a unit for monitoring the traffic on the superframe basis and regulating an excessive traffic.

Lightwave network data communications system

A loose source routing method is provided to transfer an IP packet from a transmission source gateway to a transfer destination gateway by way of ATM nodes, which are freely designated. At the transmission source gateway, the IP packet given from a user LAN is dissolved into ATM cells containing a BOM cell whose destination address designates the transfer destination gateway. In addition, at least one pseudo BOM cell whose destination address designates an ATM node in the ATM network is added and is located at a top place of a cell stream constructed by the dissolved ATM cells. Thus, the cell stream is transferred from the transmission source gateway to the designated ATM node in accordance with the destination address of the pseudo BOM cell. The designated ATM node discards the pseudo BOM cell so that the original BOM cell is now located at the top place of the cell stream. Then, the cell stream is transferred from the ATM node to the transfer destination gateway in accordance with the destination address of the BOM cell. The transfer destination gateway assembles the ATM cells into the IP packet, which is then sent to a user LAN.

Loose source routing method of IP packet on ATM network

In an ATM connectionless communication system for delivering connectionless datagram in the form of sessions through an ATM network, each one of multiple edge units is connected to a user network where quality-of-service (QoS) sessions and No-QoS sessions are mixed. Each of the edge units accommodates an IPv,packet from the user network into an intermediate frame and accommodates the intermediate frame into ATM cells. The edge units are connected to core units by permanent virtual paths to form a connectionless network. Each of the edge units has a session supervising section for determining whether the IPv,packet is a QoS session or a No-QoS session, to allocate a control flow number to the IPv,packet when the IP,packet is a QoS session.

ATM connectionless communication system having session supervising and connection supervising functions

The present invention provides a gateway unit which comprises a detecting unit for detecting the congestion from an RM cell from the ATM cell, for discriminating a TCP data gram (TCPDG) from a packet received during the congestion and for acquiring a sequence number of the TCPDG, a sending unit for sending an ACK having a window-controlled value to a transmitting terminal so as to limit a data transmission, and a discarding unit for discarding the packet from the transmitting terminal during the congestion after the confirmation of packet. During the congestion in the ATM network, a pseudo acknowledgment is sent from the gateway unit so as to indicate that the receiving terminal cannot receive data. This restrains the transmission of TCPDG from the transmitting terminal.

Method and apparatus for controlling a flow between terminals in an ATM network

In a high-speed routing control system, plural path candidates each leading to a destination node are selected on the basis of physical connection information of links connecting respective nodes in a path candidate selection unit 11, and a path candidate containing no congestion-occurring link is specified as the optimum path from the plural path candidates selected by the path candidate selection unit 11 in an optimizing unit 12. Accordingly, even when the destination node is nearer to the self node, the optimum path selection can be performed, and a switching operation to a bypass path can be performed at high speed. In addition, the traffic amount based on topology information can be suppressed, and the large-scaling of the network can be supported.

High-speed routing control system

In a connectionless communication system, a number of interworking units are provided for accommodating local area networks. At the internetworking units, a packet from the local area networks are segmented into cells for transmission to an ATM network. The cells contain a connectionless address designating a designation local area network, a virtual path identifier (VPI) designating a permanent virtual connection, and a virtual channel identifier (VCI) identifying the packet. The ATM network includes a number of cross-connect nodes interconnected by communication links. The cross-connect nodes establish a plurality of permanent virtual connections between the interworking units and the nodes and between the nodes in pairs, receive the cells from the interworking units and route the cells having VCIs of the same value through the permanent virtual connections to a destination interworking unit according to the connectionless address and the VPI contained in the cells. The destination interworking unit assembles the cells having VCIs of the same value into a packet for routine the packet to the destination local area network according to the connectionless address transmitted by the packet.

Connectionless network for routing cells with connectionless address,

A video tape recorder enables a normal video signal for an aspect ratio of 4:3 or a wide-picture video signal for a greater aspect ratio of, for example, 16:9 to be selectively recorded/reproduced onto and from a magnetic tape. In order to identify which of the aspect ratios the reproduced video signal is based on, a recording mode signal indicative of the aspect ratio is recorded on the magnetic tape together with the video signal. A code signal or a pilot signal is used for the recording mode signal. In the reproducing operation, the aspect ratio of a reproduced picture is recognized from the recording mode signal, and a signal indicative of the aspect ratio is delivered to an external device, such as a television set, together with reproduced video/audio signals. In a case where the reproduced picture is a wide picture and where the external device does not conform to the wide picture, the aspect ratio of the video signal is changed. A television set suited to the features of the video tape recorder is also disclosed.

Wide picture video recording/reproducing system

An apparatus and method for processing signals of an imaging device comprising a detection circuit for detecting the color temperature of a light source for illuminating an object of which the image is picked up and a circuit for varying .gamma. correction characteristics for chrominance signals, whereby the .gamma. correction characteristics are changed to reduce the gains for low level regions of input signals to .gamma. correction circuits in accordance with the color temperature, thereby enabling the final quantize noise to be reduced.

Apparatus and method for processing signals of an imaging device

In a digital signal processor for an imaging system, a first pixel signal including first and second color information items and a second pixel signal including third and fourth color information items are alternately outputted to generate an image signal, which is subdivided into a portion to be delayed by a horizontal scanning period and a portion not to be delayed such that these signals are thereafter combined to form an image signal having respective pixel signals so as to achieve a matrix processing on the resultant signal to attain red, blue, and green signals.

Digital signal processing apparatus having devices for delaying and

This invention relates to a method and apparatus for processing a color video signal. The processing method separates an input composite color video signal into a luminance signal and chrominance signal, demodulates the separated chrominance signal into color difference signals, stores the separated luminance signal and color difference signals in a memory, reads out the luminance signal and color differnece signals in units of 1-field period from the memory, implements the extension or reduction of the field period length alternately for every certain number of fields in reading out the luminance signal and color difference signals from the memory thereby to fix the phase relation between a residual chrominance signal component in the luminance signal read out of the memory and a chrominance signal produced by modulating the color subcarrier with the color difference signals read out of the memory, implements an intended signal processing for the readout signals, modulates the color subcarrier with processed color difference signals to produce a chrominance signal, and mixes the chrominance signal with processed luminance signal to produce a composite color video signal.

Method and apparatus for processing a color video signal

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Yokohama, Japan

Michio Masuda