Abstract: In a communication control method: information processing apparatuses output frames to a first communication apparatus for communication; when a failure in a link between the first communication apparatus and a first one of the information processing apparatuses is detected, the first one of the information processing apparatuses switches the forwarding direction of frames containing tag information from a direction toward the first communication apparatus to a direction toward a second communication apparatus; the management apparatus searches for a second one of the information processing apparatuses which uses the tag information in common with the first one of the information processing apparatuses; and the second one of the plurality of information processing apparatus switches the forwarding direction of frames containing the tag information used in common with the first one of the information processing apparatuses, from a direction toward the first communication apparatus to a direction toward the sec

Abstract: In a communication control method: information processing apparatuses output frames to a first communication apparatus for communication; when a failure in a link between the first communication apparatus and a first one of the information processing apparatuses is detected, the first one of the information processing apparatuses switches the forwarding direction of frames containing tag information from a direction toward the first communication apparatus to a direction toward a second communication apparatus; the management apparatus searches for a second one of the information processing apparatuses which uses the tag information in common with the first one of the information processing apparatuses; and the second one of the plurality of information processing apparatus switches the forwarding direction of frames containing the tag information used in common with the first one of the information processing apparatuses, from a direction toward the first communication apparatus to a direction toward the sec

Abstract: A transmission apparatus that automatically makes area division on the basis of a predetermined condition to lessen the labor of a maintainer. Transmission apparatus 1a, . . . , 1m, . . . make up one area. Each of the transmission apparatus 1a, . . . , 1m, . . . transmits data in the area or between areas according to its level. The transmission apparatus 1a, . . . , 1m, . . . select the transmission apparatus 1h as a network leader in the area. The transmission apparatus 1h calculates division points at which the area is to be divided on the basis of the predetermined condition. The transmission apparatus 1h selects the transmission apparatus 1a and 1b adjacent to one of the division points as area group leaders. Each of the transmission apparatus 1a and 1b changes its level so as to be able to transmit data between a new area formed as a result of division and an existing area. The transmission apparatus 1a, . . . , 1m, . . .

Abstract: An information storing unit stores therein information on a connection status of transmitting apparatuses in a network and a usage status of a line between the transmitting apparatuses as access-path detecting information. A path establishing unit establishes a test communication path having a predetermined bandwidth for a test communication between a test-access testing facility and a target transmitting apparatus to be tested by the test-access testing facility via the network, based on the access-path detecting information stored in the information storing unit.

Abstract: A transmission apparatus that automatically makes area division on the basis of a predetermined condition to lessen the labor of a maintainer. Transmission apparatus 1a, . . . , 1m, . . . make up one area. Each of the transmission apparatus 1a, . . . , 1m, . . . transmits data in the area or between areas according to its level. The transmission apparatus 1a, . . . , 1m, . . . select the transmission apparatus 1h as a network leader in the area. The transmission apparatus 1h calculates division points at which the area is to be divided on the basis of the predetermined condition. The transmission apparatus 1h selects the transmission apparatus 1a and 1b adjacent to one of the division points as area group leaders. Each of the transmission apparatus 1a and 1b changes its level so as to be able to transmit data between a new area formed as a result of division and an existing area. The transmission apparatus 1a, . . . , 1m, . . .

Abstract: An OSI tunnel routing method is provided, in which an IP packet which is encapsulated in an OSI packet is transmitted between transmission apparatuses in an OSI network each connected to an IP network. The transmission apparatuses exchange reachable IP network addresses and each own OSI network address, each of the transmission apparatuses generates an OSI tunnel table which includes the OSI network addresses and the reachable IP network addresses, and a first transmission apparatus which receives an request to access an IP address determines a second transmission apparatus which can transfer data for the IP address by referring to the OSI tunnel table, and generates an OSI tunnel between the first transmission apparatus and the second transmission apparatus.

Abstract: A transmitting apparatus provided in a network different from IP comprises IP telephone control means for implementing an IP telephone function by dealing with IP data including audio information; means for capsuling the IP data dealt with by the IP telephone control means into data suitable for the protocol of the network in which the local apparatus is provided; means for transmitting to the network the data capsuled by the capsuling means; means for receiving, via the network, data capsuled by capsuling means of another transmitting apparatus; and means for extracting IP data from the data received by the receiving means.

Abstract: An ATM cell compression recovery device includes an ATM cell recovery device having a compressed cell determination unit that determines whether an ATM cell from a transmission line is a compressed cell, a cell recovery unit that recovers the determined compressed cell in an ATM layer into an original ATM cell, and a switch that switches the recovered ATM cell. The ATM cell compression recovery device also includes a compression object cell determination unit that determines whether ATM cells received from the switch on an identified path have been compressed, and a compressed cell production unit that compresses the ATM cell in an ATM layer to be transmitted on the identified part. With this device, data is compressed and recovered in the ATM layer of the ATM network.

Abstract: An OSI tunnel routing method is provided, in which an IP packet which is encapsulated in an OSI packet is transmitted between transmission apparatuses in an OSI network each connected to an IP network. The transmission apparatuses exchange reachable IP network addresses and each own OSI network address, each of the transmission apparatuses generates an OSI tunnel table which includes the OSI network addresses and the reachable IP network addresses, and a first transmission apparatus which receives an request to access an IP address determines a second transmission apparatus which can transfer data for the IP address by referring to the OSI tunnel table, and generates an OSI tunnel between the first transmission apparatus and the second transmission apparatus.