Hitachi, Ltd.

Hitachi Communication Technologies, Ltd.

Masatoshi Takihiro

Osamu Takada

Takeshi Ishizaki

Toshihiko Murakami

Tetsuro Yoshimoto

Tohru Setoyama

Tomihisa Nishijima

Tetsuhiko Takahashi

Yusuke Yajima

Tohru Kazawa

Minoru Koizumi

Naoya Ikeda

Toshiaki Hirata

Kenichi Yoshida

Shigeru Miyake

Takahiro Yoshida

Tomoichi Ebata

Ryuji Ishii

Eri Kawai

Norihiro Sakamoto

Hidehiro Fukushima

Tokuhiro Niwa

Akihiko Tsuchiya

Tomoyuki Iijima

Koji Tsukada

Shuji Ohno

Atsushi Kimoto

Masataka Ohta

Masayuki Hino

Kengo Ijima

Yu Mitsui

Yoshiyuki Kurosaki

Provided is a passive optical network system for operating a mixture of PONs with differing transmission speeds and is capable of reducing power consumption on the basis of the amount of signals being transmitted. The master station of the passive optical network system, which determines the amount and timing of signals sent thereto by each of a plurality of slave stations on the basis of the requests of the plurality of slave stations and receives signals from the plurality of slave stations via an optical fiber network, is equipped with a control unit that determines in each set cycle the amount, transmission timing, and transmission speed of the signals that each slave station is permitted to transmit to said master station on the basis of the amount of signals that each of the plurality of slave stations has requested to transmit, and that notifies such to each slave station. Additionally, each of the plurality of slave stations is equipped with a control unit that transmits signals to the master station at a first transmission speed or a second transmission speed that is faster than the first transmission speed, and is configured to transmit signals with either the first transmission speed or the second transmission speed on the basis of notifications from the master station.

Passive optical network system and operating method thereof

In a broadband access network, calls can be kept active even when a telephone network fails. A voice gateway function captures callee telephone number information sent from a caller subscriber telephone to the telephone network and, when the telephone network fails, keeps the call active by retaining the connection between the caller and the callee. Furthermore, when the telephone network fails, the operation mode of the voice gateway and all ONTs is switched from an H.248 gateway mode to an SIP softswitch mode, allowing the voice gateway function to relay communication packets between ONTs and new call connections to be made in the broadband access network.

Gateway device, optical network terminal, and passive optical network system

An object of the present invention is to solve a problem that when multicast is utilized in a network configured with virtual routers, traffic in the relay network is increased. According to the present invention, the number of multicast packets via the relay network is reduced by performing a multicast packet transfer across the virtual routers within the same router. Specifically, it is allowed to register in a multicast routing table held by each virtual router, a line interface identifier of another virtual router as outgoing line interface information, whereby multicast packet transfer from a virtual router to another virtual router is made possible. In order to specify a virtual router to share the multicast packet, each virtual router holds information to specify a virtual router having a line interface to receive the multicast traffic indicated by the multicast group address.

Multicast packet relay device adapted for virtual router

In a packet transmission router used in a VRRP (Virtual Router Redundancy Protocol) network having a VR (Virtual Router) function, when virtual routers VR are realized by the VRRP, the routing control information that each VR manages is prevented from being mixed with that of other VR. When an active packet transmission router transmits a VRRP packet to a standby packet transmission router, an identifier indicating which virtual router belongs to the VRRP packet is added to the VRRP packet before the transmission of the VRRP packet.

VRRP technology keeping VR confidentiality

A packet transfer apparatus connected to an internal subnetwork formed by a set of broadcast segments each accommodating terminals and for transferring, when a MAC frame including a IP address which designates a destination terminal connected to one of the segments is received from a terminal connected to another segment in the internal subnetwork, an IP packet in the MAC frame to the segment connected to the destination terminal in accordance with a terminal management table which indicates a relation of address information of each of the terminals belonging to the internal subnetwork and the segment to which the terminal is connected.

Packet transfer apparatus connectable with mobile terminals

The object of the present invention is to provide a communication network system that reduces the burden of entering settings for the network system. A service directory server in the communication network system provides unified management of the service information of the service-providing server installed in the network. The service information managed by the service directory server is distributed to the communication nodes either automatically or in response to requests from a communication node. The communication nodes receive packets and, for received packets that are addressed to itself, a service-providing server destination is determined based on the service information provided by the service directory server and the packet is transferred to the server to receive the service.

Communication network system and method for controlling services in a communication network system

A network system having a plurality of interconnected networks each having a policy server. The policy server sets a quality-guaranteed path in the network according to a policy held in the policy server. The policy server includes: a policy holding unit to hold a policy defining a quality that can be guaranteed in its own network, or local network, for an inter-network communication; a policy publicizing unit to make public the policy held in the policy holding unit to the policy servers of other networks; a guaranteed quality calculation unit to calculate, from a policy publicized by a policy server of a network on a path between the local network and other network, a quality that can be guaranteed for the path between the local network and the other network; and a quality-guaranteed path setting unit to provide a quality-guaranteed path, the quality-guaranteed path having a guaranteed quality within the quality calculated by the guaranteed quality calculation unit for the path between the local network and the other network.

Network system having plural networks for performing quality guarantee among the networks having different policies

Switches create and manage routes with route control protocols such as BGP-4, PNNI, etc. and a route management apparatus is notified of the information of the routes, created by these protocols, and the route management apparatus verifies the validity of a route of which the apparatus is notified by a switch based on the route information of the whole network composed of the plurality of pieces of information given by respective switches and the management policy set by a network manager. In the verification of validity, it is confirmed that the transmitted data are able to arrive at the destination securely and the set route is not against the management policy, and the route-usage-permission-notice of a route confirmed of its validity by the route management apparatus is transmitted to respective switches. Thereby, in the route control of a network using a route control protocol, it is made possible to prevent the occurrence of an abnormal route caused by the difference in the speed of operations of respective switches or an erroneous setting of a switch.

Network system having route verification function and the component apparatuses and method thereof

A user terminal sends a resource reservation request message in which time information indicative of time to perform a communication is designated to a switching node to which the self user terminal is linked. The switching node manages a reservation state of each of resources which can be used by the self switching node among resources of a network together with time information indicative of time when a communication using the resource is performed. When the resource reservation request message is received, an unreserved resource is obtained at a time indicated by the time information designated in the resource reservation request message, the obtained resource is reserved, and a resource reservation result notice message indicative of the reservation result is returned to the user terminal. A resource management server is also provided so as to reserve a network resource with a simple operation. The reservation can be performed in consideration of priority and cost of a communication. Reservation information can be always recognized by a client. When resource reservation is failed, an alternative plan is automatically calculated and presented.

Network and switching node in which resource can be reserved

An ATM switch and a congestion control method are provided to handle connection setup requests from other ATM devices. In the ATM switch, a congestion detecting process detects congestion of a class that has a number of the connection setup requests stored by class in the buffer equal to T(x), a predetermined number of the connection setup requests to be stored for each of the classes. A message discarding process discards the received connection setup request if it belongs to the congested class. Furthermore, a priority control method for receiving connection setup requests is provided to establish connections more efficiently. A branching process detects a port to which the connection setup request is inputted, identifies a priority class which corresponds to the port using a priority table, and stores the connection setup request in one of queues which are provided for each priority class. An extracting process extracts the connection setup request from the queue of the priority class to be extracted according to a predetermined algorithm.

ATM switch congestion control method of connection setup requests and priority control method for receiving connection requests

An ATM switching system provided with a plurality of call processing devices, a plurality of line interfaces for inputting and outputting an ATM cell, an ATM switch connected to the plurality of line interfaces for switching the ATM cell, and a switch control portion connected to the ATM switch, the plurality of line interfaces and a plurality of call processing devices. Requirement information related to call processing input from line interfaces is collected once in the switch control portion. The switch control portion determines to which of the plurality of call processing devices the requirement information is to be distributed based on the information related to the input-output line, a state of processing capability of the call processing device, etc. The related line interface is set directly from switch control portion through a bus based on the control information from determined one or a plurality of call processing devices.

ATM switching system including a switching control portion for

An ATM switch for providing an electrical interconnection between a connection-oriented ATM LAN of an ATM system and a connectionless legacy LAN is provided. The ATM switch includes a switch fabric electrically connected to the ATM LAN, a segmentation and reassembly block electrically connected to the switch fabric, for providing an interchange between one of cells transmitted over the ATM LAN and a packet transmitted over the legacy LAN, a management and control block electrically connected to the switch fabric through the segmentation and control block so as to manage and control operations for electrical connections between networks, a first bridging/routing processor having a legacy LAN interface for providing electrical connections between the legacy LAN and the first bridging/routing processor, a second bridging/routing processor electrically connected to the switch fabric through at least one ATM interface, and a bus for providing electrical connections between the management and control block, the first bridging/routing processor and the second bridging/routing processor. A LAN emulation configuration server function for managing configurations of a plurality of virtual LAN segments on the ATM LAN, which are required upon LAN emulation, a LAN emulation server function for obtaining an address resolution to an ATM address from a media access address, and a broadcast and unknown server function for making a broadcast to a terminal in the LAN are provided so as to be distributed to the management and control block or the second bridging/routing processor.

Growing community of inventors

Yokohama, Japan

Masatoshi Takihiro