Communication device and communication system

A communication system comprising a first communication device and a second communication device for dividing each of a plurality of TCP communications between computers into three TCP communications, and relaying them,

• wherein the first communication device makes a first TCP communication with a data transmission computer,
• the second communication device makes a second TCP communication with a data reception computer,
• a third TCP communication is made between the first communication device and the second communication device, and
• the first communication device makes a first determination as to packet transmission availability based on a communication bandwidth per session based on the regulation of the third TCP communication and a second determination as to packet transmission availability based on a maximum bandwidth of the third TCP communication previously set before the start of communication by use of a token bucket algorithm, and when the first determination and the second determination indicate transmission available, transmits packets.

A communication method for dividing each of a plurality of TCP communications between computers into three TCP communications, and relaying data transfer,

• wherein a first communication device makes a first TCP communication with a data transmission computer,
• a second communication device makes a second TCP communication with a data reception computer,
• a third TCP communication is made between the first communication device and the second communication device, and
• the first communication device makes a first determination as to packet transmission availability based on a communication bandwidth per session based on the regulation of the third TCP communication and a second determination as to packet transmission availability based on a maximum bandwidth of the third TCP communication previously set before the start of communication by use of a token bucket algorithm, and when the first determination and the second determination indicate transmission available, transmits packets.