Hitachi, Ltd.

Hitachi Hybrid Network Co., Ltd.

Shinji Nozaki

Sunao Sawada

Kazuaki Tsuchiya

Hidemitsu Higuchi

Tatsuya Watanuki

Ken Watanabe

Masashi Suzuki

Hiroyuki Isogai

Manabu Fujita

A communications apparatus for converting an IPv4 multicast packet transmit from an IPv4 terminal into an IPv6 multicast packet and transmitting the converted IPv6 multicast packet to one of a plurality of IPv6 networks. The communications apparatus has information indicating to which IPv6 network the IPv4 multicast packet to undergo conversion processing is to be transmitted. The communications apparatus then converts the received IPv4 multicast packet into an multicast packet and transmits the converted IPv6 multicast packet to an IPv6 network where it is required to be sent.

Multicast routing method and apparatus for routing multicast packet

The network relay device of the invention carries out data transmission to and from an opposite device to relay data in a network. The network relay device includes: multiple ports connecting with corresponding multiple ports of the opposite device via multiple links; and a link aggregation control module that aggregates the multiple links to establish a link aggregation, which is regarded as one logic link, and carries out transmission of a control frame signal including a synchronization bit, as well as data transmission, at each port via the link aggregation. In response to detection of occurrence of a trouble in at least one of the aggregated multiple links, the link aggregation control module causes a port that connects with a normal link without the trouble among the multiple ports to stop the data transmission and send the control frame signal including the synchronization bit set equal to a first value. Here the first value functions to stop the data transmission at a corresponding port of the opposite device connecting with the normal link.

Network relay system and control method thereof

A multicast communication method for allowing a communication control apparatus for communicating in accordance with IPv4 to communicate with a communication control apparatus for communicating in accordance with IPv6. This method includes the steps of: when an IPv4 multicast packet is inputted, discriminating that this packet is a data packet on the basis of an IPv4 header; when it is determined that the packet is the data packet, converting the IPv4 header of the IPv4 multicast packet into an IPv6 header; generating an IPv6 multicast packet; and outputting the generated IPv6 multicast packet to a IPv6 network.

Multicast communication method

A communications apparatus for converting an IPv4 multicast packet transmit form an IPv4 terminal into an IPv6 multicast packet and transmitting the converted IPv6 multicast packet to one of a plurality of IPv6 networks. The communications apparatus has information indicating to which IPv6 network the IPv4 multicast packet to undergo conversion processing is to be transmitted. The communications apparatus then converts the received IPv4 multicast packet into an IPv6 multicast packet and transmits the converted IPv6 multicast packet to an IPv6 network where it is required to be sent.

A communications apparatus for converting an IPv4 multicast packet transmit from an IPv4 terminal into an IPv6 multicast packet and transmitting the converted IPv6 multicast packet to one of a plurality of IPv6 networks. The communications apparatus has information indicating to which IPv6 network the IPv4 multicast packet to undergo conversion processing is to be transmitted. The communications apparatus then converts the received IPv4 multicast packet into an IPv6 multicast packet and transmits the converted IPv6 multicast packet to an IPv6 network where it is required to be sent.

A communication unit is connected to both an IPv4 network and an IPv6 network for converting an IPv4 multicast packet into an IPv6 multicast packet. The communication unit, which has held the IPv6 multicast addresses, holds the IPv4 multicast addresses of a multicast group on the IPv4 network and the held IPv6 multicast addresses in correspondence with each other. Moreover, the communication unit converts the IPv4 multicast address of the received IPv4 multicast packet into the IPv6 multicast address held in correspondence with the IPv4 multicast address, then transmits the multicast packet to the IPv6 network.

Multicast routing method and an apparatus for routing a multicast packet

A LAN switch is one component of a communications network system composed of a virtual LAN having network terminals such as personal computers connected with ports respectively. The LAN switch provides a host table for holding correspondence between each port and address information of the network terminal connected to each port and an authentication table for holding information for authenticating a user of each network terminal. If a request takes place of changing the correspondence about the source network terminal held in the host table when relaying the packets, the LAN switch prompts a user name and a password for the source network terminal, does user authentication on the basis of the information held in an authentication table, and enables rewrite of the host table and relay of the packets if the user is correct. These processes are executed for easily preventing false use of an address or tapping or false access by a malignant user as well as analyzing or recovering the erroneously set address.

Communications control method and information relaying device for communications network system

In an information network having a complex structure made of a logical network and also a physical network, such an information network is constituted so as to realize a multicast service capable of not increasing an amount of a network traffic larger than a necessary traffic amount. This information network contains a plurality of information relay apparatuses for relaying information among a plurality of VLANs (Virtual Local Area Networks), a network for connecting these information replay apparatuses to each other, a multicast server and a plurality of terminals, belonging to an arbitrary VLAN of these VLANs. A multicast relay processing unit, a multicast address learning processing unit, and a multicast learning table are provided in each of these information relay apparatuses so as to register a predetermined relay destination of a multicast communication. Even in such a case that the VLAN structure is made complex irrespective of the physical network structure, it is possible to distribute such a multicast packet suitable for the physical network structure.

Network relay apparatus

A packet communications apparatus of the present invention essentially comprises a plurality of network interfaces (NIFs), a learned address table, a packet forwarding unit (PFU) and a processor for directive packets to change state (PDPCS). The learned address table contains information for identifying a NIF through which to send a packet. The PFU selects a port through which to forward a packet by referring to the learned address table, according to the state of the NIFs, and forwards or discards a packet received from a user terminal. The PDPCS receives a packet including a directive to change the state of a specific NIF to one of the connected state, disconnected state and stateless. The PDPCS changes the state of the specific NIF to one of the connected state, disconnected state and stateless, according to the directive in the packet.

Communication apparatus for routing or discarding a packet sent from a user terminal

A communicating apparatus is disclosed which has been connected to both of the IPv4 network and the IPv6 network for converting an IPv4 multicast packet into an IPv6 multicast packet. The communicating apparatus, which has held the IPv6 multicast addresses, holds the IPv4 multicast addresses of a multicast group on the IPv4 network and the held IPv6 multicast addresses in correspondence with each other, said communicating apparatus having been a member of said multicast group. Moreover, the communicating apparatus converts the IPv4 multicast address of the received IPv4 multicast packet into the IPv6 multicast address held in correspondence with the IPv4 multicast address, then transmitting the multicast packet to the IPv6 network.

An information relay device connected between a plurality of logical or physical networks for performing an operation for relay of information between the networks is provided with a transmit/receive processing unit for receiving a general purpose multicast message from one of the plurality of networks and transmitting a multicast message to at least one of the plurality of networks, and a protocol conversion processing unit for converting, in the case where the general purpose multicast message received by the transmit/receive processing unit is a multicast protocol message of a certain level layer, the multicast protocol message of the certain level layer into a multicast protocol message of another level layer.

Growing community of inventors

Yokohama, Japan

Shinji Nozaki