Hitachi Cable, Inc.

Hitachi Metals, Ltd.

Koichiro Seto

Tomoyoshi Tatsumi

Shingo Sugawara

Akihiro Sekiguchi

Kenji Aoshima

Hitoshi Kuwata

Daisuke Adachi

Masaru Kuriyama

A network system has lower switches and upper switches connected to the lower switches. Each of the upper switches includes a connection information notifying means for notifying connected lower switch list informations each of which includes an identification information on each of the lower switches connected to each of the upper switches, to the lower switches connected to each of the upper switches. Each of the lower switches includes a comparison determination means for comparing the connected lower switch list informations notified by the connection information notifying means, in order to determine a connection state between the upper switches and the lower switches.

Network system

A network system includes lower switches and upper switches connected to the lower switches. Each of the upper switches transmits a first notification frame containing a connected lower switch number information indicative of the number of the lower switches connected to each of the upper switches, to the lower switches connected to each of the upper switches. Each of the lower switches configures a link aggregation group for ports which received the first notification frames each of which contains a maximum value of the connected lower switch number information among the connected lower switch number informations contained in the received first notification frames.

A ring network with plural network relay devices connected in a ring shape includes first and second control ports to be transitioned into either a forwarding state that permits relaying information, or a blocking state that prohibits relaying information; and a ring protocol control unit for transmitting connection confirmation information indicative of communications being possible between the first and the second control port, from the first to the second control port, and from the second to the first control port at a predetermined time interval, or for, in the event that the first or the second control port does not receive the connection confirmation information from the second or the first control port, transmitting failure information indicative of communications being not possible between the first and the second control port, from the first to the second control port, or from the second to the first control port. The ring protocol control unit transitions the first control port into the blocking state when the first control port receives the failure information, or into the forwarding state when the first control port transmits the failure information. The ring protocol control unit transitions the second control port into the blocking state when the second control port receives the failure information, or into the forwarding state when the second control port transmits the failure information.

Ring network and network relay device

A switching hub for processing a VLAN frame transmitted through a transmission line of a ring network includes two ring ports connected to the transmission line of the ring network, and a forwarding processing mechanism for, when one of the two ring ports receives the frame and when a VLAN in which the received frame belongs is a VLAN only through both the ring ports, forwarding the frame to the other ring port without performing FDB learning on the frame.

Switching hub and ring network

A network relay device is for receiving, from an external network relay device, connection confirmation information indicative of being in communication connection with the external network relay device. When the connection confirmation information is particular connection confirmation information indicative of being transmitted from a predetermined external network relay device, the network relay device provides return confirmation information to the predetermined external network relay device.

Network relay device, network connection confirmation method, and network

A switching hub is provided with a control unit for setting, for a port, a VLAN-ID comprising a subgroup ID of a subgroup constituting a VLAN, and a sub-ID of a group contained in the subgroup ID, and a switching processing unit for relaying a frame, which contains the VLAN-ID, via the port, which matches the VLAN-ID.

Switching hub and LAN system

A reply communication apparatus conforms to a protocol to return a reply electronic document in reply to a request electronic document sent from a communication apparatus. The apparatus has a hardware to perform a reply process in the protocol, and is operable to rewrite contents of the request electronic document to replace the request electronic document into a reply electronic document and to output the reply electronic document.

Reply communication apparatus and ARP reply communication apparatus

To provide a transmitter/receiver and a method for a multiplexing transmission and reception of transmission signals of Gigabit Ethernet, without needing a great buffer memory, nor processes for adding channel identification numbers to frames or for removal, at a multiplexed signal transmitter in which data signals input from a plurality of channels of Gigabit Ethernet are multiplexed to be transmitted, a particular 10-bit data word is transmitted before transmission of a data input from a particular channel, and at a multiplexed signal receiver, the particular channel is identified by the 10-bit data word to be present or not.

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Amimachi, Japan

Koichiro Seto