Session relay device, session relay method, and session relay program

Abstract

In a data reception processor ( 210 a) in a session relaying apparatus ( 20 - 3 ), a data amount monitor ( 201 ) monitors the data amount within the session relaying apparatus ( 20 - 3 ), a receivable amount calculating unit ( 212 ) requires a data receivable amount which is informed from the session relaying apparatus ( 20 - 3 ) to a data transmission terminal ( 10 ) in a devaluating way according to a predetermined function, a receivable amount informing unit ( 213 ) informs the data transmission terminal ( 10 ) of the value, and in the data output processor ( 220 a), an initialization judging unit ( 223 ) makes a judgment about initialization of the transmission amount, according to the amount resulting from the data monitor ( 201 ) monitoring the data amount within the session relaying apparatus ( 20 - 3 ), and a transmissive amount calculating unit ( 222 ) determines the data transmissive amount by using the result.

Description

technical field [0001] The present invention relates to a session relay device for relaying a session between a data sending terminal and a data receiving terminal and a session relay method for the device. Background technique [0002] In the above-mentioned session relay device and the session relay method used in the device, the term "session" means continuing communication with one meaning, and data packets in the session are received and sent according to a certain control policy. Therefore, it includes content using a protocol such as setting up a connection such as ATM, TCP, SCTP, and UDP, and disconnecting the connection after the communication ends. [0003] Figure 6 It is a schematic diagram showing a technical field using a session relay device. In the following, for simplicity of description, TCP is taken as an example for description. [0004] Conventionally, as one of techniques for increasing the throughput of a TCP session, there is a method of relaying th...

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Problems solved by technology

Therefore, the throughput between the data transmission terminal 10 and the session relay device 20 is reduced (reference document 4, J. Postel, "Transmission control protocol", RFC793, Sept 1981. (hereinafter referred to as document 5))

[0022] The second problem is that, in the first mode described above, when there is no data stored in the data storage unit 231 of the session relay device 20, the throughput improvement effect is limited.

As a result, the transmittable amount from the session relay device 20 to the data receiving terminal 30 becomes smaller due to no congestion occurring between the session relay device 20 and the data receiving terminal 30, so that the session relay device 20 The throughput with the data receiving terminal 30 is reduced (Reference 4, M. Allman, "TCP Congestion Control", RCC2581, April 1999. (hereinafter referred to as Document 6))

[0024]The third problem is that in the second and third methods above, there is a problem that terminal changes become necessary

[0026] The fourth problem is that in the above-mentioned second and third methods, there are problems such as network congestion in the normal network

For this reason, when the second and third methods are used in a normal wired network, even if data packets are discarded due to congestion, since the data transmission terminal 10 does not reduce the transmission rate, there is still a possibility that the network congestion will increase.

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