Abstract: A transmitter and a receiver each have an apparatus for carrying out retransmission processing at a TCP layer and an apparatus for carrying out encrypted-data communication at an IPSec layer. The apparatus operating at the IPSec layer has a buffer for storing encrypted data transmitted by the transmitter. When a request for retransmission of data is received from the receiver, in spite of an operation carried out at an IP layer, information available at the TCP layer is obtained and data corresponding to the encrypted data stored in the buffer is returned to the receiver in response to the request.

Abstract: A communication control apparatus for enabling a quality of service (QoS) to be maintained, the security against interception to be ensured, and a communication route to be switched over without any interruption of communications, and capable of restraining the processing time and the number of adjusting parameters. The communication control apparatus including a coding unit, an allocation unit, and a sending unit.

Abstract: To provide a technology capable of ensuring a communication traffic on a communication route simply by providing a communication node with this technology in a network such as the Internet where communication control devices on communication routes employed for forwarding data are not all uniformly managed. A communication traffic of a first flow that contributes to a band of communication with a partner communication device is measured, a communication traffic of a second flow is calculated so that a total communication traffic of the first flow communication traffic measured and the communication traffic of the second flow that can be generated based on a result of the measurement, converges at within a predetermined range, and the communication traffic of the second flow is generated with respect to the partner communication device on the basis of a result of the calculation.

Abstract: To provide a technology enabling a quality of service (QoS) to be kept, the security against interception to be ensured and a communication route to be switched over without interruption of communications, and capable of restraining processing time and the number of adjusting parameters.

Abstract: A transmitter redundantly transmits data in an available band range when transmitting data. A receiver discards redundancy and receives the data. The receiver also redundantly transmits ack in an available band range. Since data is redundantly transmitted/received, there is a high possibility that data may reach the opposite party normally even if one of the duplicate data is lost. Accordingly, high-speed communication can be realized. Since time no data flows through a communication route is reduced, network resources can be effectively utilized.

Abstract: A transmitter redundantly transmits data in an available band range when transmitting data. A receiver discards redundancy and receives the data. The receiver also redundantly transmits ack in an available band range. Since data is redundantly transmitted/received, there is a high possibility that data may reach the opposite party normally even if one of the duplicate data is lost. Accordingly, high-speed communication can be realized. Since time no data flows through a communication route is reduced, network resources can be effectively utilized.

Abstract: A transmitter and a receiver each have an apparatus for carrying out retransmission processing at a TCP layer and an apparatus for carrying out encrypted-data communication at an IPSec layer. The apparatus operating at the IPSec layer has a buffer for storing encrypted data transmitted by the transmitter. When a request for retransmission of data is received from the receiver, in spite of an operation carried out at an IP layer, information available at the TCP layer is obtained and data corresponding to the encrypted data stored in the buffer is returned to the receiver in response to the request.