Abstract: A communication apparatus contains a first table having entries each storing a data-link-layer path to a second communication apparatus, and a second table storing a pointer to the entry of the first table, storing the data-link-layer path to the second communication apparatus, corresponding to a network-layer address of one of the at least one other communication apparatus. In addition, a process for determining layer-2 reachability between first and second communication apparatuses, identifies first and second layer-2-connected communication networks to which first and second interfaces of first and second routers are connected, where, on a layer-3 communication path between the first and second communication apparatuses, the first router is located nearest the first communication apparatus and the second router is located nearest the second communication apparatus. When first and second layer-2-connected communication networks are identical, the layer-2 reachability is determined.

Abstract: A control device includes a virtual IF set to associate with address information of an interface on a forwarding device and, when detecting that an application section accesses the virtual IF, requests the forwarding device to set a packet transfer rule for transferring a packet received on an interface to the control device while making the packet associate with the virtual IF. The forwarding device sets the packet transfer rule requested by the control device.

Abstract: An end equipment (including a terminal equipment and a router) executes a destination address resolution of a data packet. In a network layer, when a packet transmitter detects that a direct route of an input packet is not registered in a routing table a path manager transmits an inquiry packet, demands a preparation of a point-to-point logical interface of the direct route based on a data link layer address of the destination included in the received response packet, and registers the prepared logical interface in the routing table.

Abstract: A frame forwarding system which has a plurality of frame forwarding devices and links to transport frames between external networks that belong to a particular group. This system is designed to prevent backbone links from being blocked even when there is a backdoor link that forms a potential loop in the network. A system state sharing unit in a frame forwarding device shares system state information with other frame forwarding devices. This information sharing enables all the frame forwarding devices and inter-node links to behave as a single virtual device for forwarding frames between external networks that belong to a particular group. A frame forwarding processor forwards received frames according to the system state information shared among all the frame forwarding devices in the system.

Abstract: A connection-oriented communication interface management system which permits a connection-oriented multiplexed communications network to fully enjoy the advantages of ATM technologies, by giving more flexibility to a link management mechanism that associates connection-oriented communication interfaces with virtual channels. The system comprises a virtual channel set-up unit and an interface set-up unit. The virtual channel set-up unit establishes a virtual channel to reach a peer (remote) node. Separately from this channel, the interface set-up unit establishes a connection-oriented communication interface to communicate with the peer node. At the same time, the interface set-up unit defines association between the established connection-oriented communication interface and the virtual channel established by the virtual channel set-up unit.

Abstract: A packet relaying apparatus is structured to comprise a network relaying function for selecting one or more networks allowed to relay an received packet based on the transmission source network identifier corresponding to the received packet, a domain relaying function for selecting one or more routing domains corresponding to one or more networks, a routing information management function for collating the transmission destination address of the packet with each routing domain information of one or more routing domains to select the next hop router address for transmitting the packet to the next packet relaying apparatus, and a packet relaying function for transmitting the packet to the transmission destination address.

Abstract: In a virtual network construction method, a virtual network construction system, and a relaying apparatus within a public data communication network, control packets each having set a multicast address are multicast, and upon reception of the control packets by the relaying apparatuses belonging to the multicast address group, virtual links to the transmitting sources of the control packets are established and reply packets are returned through the virtual links, whereby the virtual links are established between all of the relaying apparatuses belonging to the multicast address group to establish the virtual network.

Abstract: A technology in a relay system for relaying communication data between a plurality of domains by an address translation, is capable of executing, even when there are both streams of inter-domain and intra-domain communications, the communications with security ensured without setting a complicated packet filter between the domains, and routing a packet at a high speed within the domain.

Abstract: A relay system, comprises interface units for accessing networks, a domain definition module, an connection definition module, a routing module, an address translation module for translating, when forwarding a communication data from one domain to another domain, a source address belonging to the source domain contained in the packet into a proxy host address belonging to the routing destination domain, and an address reverse translation module for translating, when receiving a communication data which has the proxy host address in destination address field, the destination address belonging to the source domain contained in the packet into the address belonging to the routing destination, and a control unit for controlling a connectability for routing between the two or more domains in accordance with definitions of the connection definition module.

Abstract: A communication apparatus contains a first table having entries each storing a data-link-layer path to a second communication apparatus, and a second table storing a pointer to the entry of the first table, storing the data-link-layer path to the second communication apparatus, corresponding to a network-layer address of one of the at least one other communication apparatus. In addition, a process for determining layer-2 reachability between first and second communication apparatuses, identifies first and second layer-2-connected communication networks to which first and second interfaces of first and second routers are connected, where, on a layer-3 communication path between the first and second communication apparatuses, the first router is located nearest the first communication apparatus and the second router is located nearest the second communication apparatus. When first and second layer-2-connected communication networks are identical, the layer-2 reachability is determined.

Abstract: A communication apparatus contains a first table having entries each storing a data-link-layer path to a second communication apparatus, and a second table storing a pointer to the entry of the first table, storing the data-link-layer path to the second communication apparatus, corresponding to a network-layer address of one of the at least one other communication apparatus. In addition, a process for determining layer-2 reachability between first and second communication apparatuses, identifies first and second layer-2-connected communication networks to which first and second interfaces of first and second routers are connected, where, on a layer-3 communication path between the first and second communication apparatuses, the first router is located nearest the first communication apparatus and the second router is located nearest the second communication apparatus. When first and second layer-2-connected communication networks are identical, the layer-2 reachability is determined.