JP3008695B2 - Window size negotiation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a window size negotiation method, and more particularly to a window size negotiation method for adjusting an information amount of data communication performed between a plurality of computers constituting a communication network.

[0002]

2. Description of the Related Art A conventional window size negotiation method is used as one of flow control functions for avoiding a decrease in service caused when a large amount of information flows into a communication network or computer resources. A typical example is a packet switching network protocol (CCITT Recommendation X.2).
The packet-level flow control 5) will be described.

FIG. 2 is an explanatory diagram for explaining a procedure of an incoming call receiving operation. First, the negotiation of the window size is the calling DTE
A request function for window size is provided in the facility part of the CR packet 21 in response to an outgoing call request from the DCE, and when a call is received from the DCE to the incoming DTE, the request in the facility part of the CN packet 22 is transmitted to the facility part of the CR packet 21. A function for designating a window size smaller than the existing window size is provided.
The facility part of the packet 23 is “1 or 2” when the window size of the facility part of the CN packet 22 is “1”, and “2 or more” when the window size of the facility part of the CN packet 22 is “2 or more”. And
A designation function for designating a window size of a value smaller than or equal to the window size of the facility portion of the CN packet 22 is provided. When the connection from the DCE to the calling DTE is completed, the facility portion of the CC packet 24 Unit has a designating function for designating the same value as the designated window size. Each of the CR packet 21 from the calling DTE, the CN packet 22 from the DCE, the CA packet 23 from the incoming DTE, and the CC packet 24 from the DCE The window size is negotiated by designating the window size in the facility portion of the CA packet 23. Eventually, the value designated in the facility portion of the CA packet 23 becomes the maximum value of the data packet which can be continuously transmitted and received without a response confirmation. It is determined as a window size which is a number.

[0004]

In the conventional window size negotiation method described above, the window size to be determined is
Since both the calling DET and the called DET are the maximum number of data packets that can be continuously transmitted and received without the response confirmation of the called DET, the maximum number of data packets that can be continuously transmitted and received in the calling DET is equal to the maximum number of data packets of the called DET. Even if it is larger than the maximum number of data packets that can be continuously transmitted and received,
However, there is a problem that the transmission / reception buffer cannot be used effectively.

SUMMARY OF THE INVENTION It is an object of the present invention to specify different window sizes on the calling side and the called side even when the size of the transmission / reception buffer differs between the calling side and the called side. Another object of the present invention is to provide a window size negotiation method that can effectively utilize the transmission / reception buffers of the respective devices.

[0006]

According to the present invention, there is provided a window size negotiation system for adjusting an information amount of data communication performed between a plurality of computers constituting a communication network. Is a start notification transmission processing means for starting when the self becomes the transmission station of the data communication and transmitting a start notification message in which the maximum number of continuously receivable messages is set at the start of the data communication, and transmission of another computer. Window size setting means for comparing the maximum number of continuously receivable messages included in the start notification message and the notification start response message with its own maximum number of continuously receivable messages and setting the smaller value as its own window size When the start notification message transmitted from the other computer is received, the maximum number of continuously receivable messages is set. A configuration and a start notification response transmission processing means for transmitting the start notification response message.

[0007]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

The window size negotiation method according to the present invention is arranged such that each of a plurality of computers 1 and 2 constituting a communication network is activated when the computer itself is a transmitting station of data communication and receives its maximum continuous reception at the start of data communication. A start notification transmission processing unit 3 for transmitting a start notification message in which the number of possible messages is set,
Compare the maximum number of continuous receivable messages contained in the start notification message and the notification start response message sent by the computer that is the data communication partner with your own maximum number of continuously receivable messages, and compare the smaller number to your own window. A window size setting processing unit 4 to be set as a size, and a start notification response transmission to transmit a start notification response message in which the maximum number of continuously receivable messages is set when receiving a start notification message transmitted from a computer which is a data communication partner. And a processing unit 5. However, in the case of this embodiment, for convenience of explanation,
The start notification transmission processing unit 3 is described only in the computer 1 serving as the transmitting station, and similarly, the start notification response transmission processing unit 5 is described only in the computer 2 serving as the receiving station.

Next, the operation will be described.

A start notification transmission processing unit 3 in the computer 1
In the start notification message (hereinafter referred to as REQ) 6, a start notification message type (hereinafter referred to as REQ-TYPE) 7 and a maximum number of continuously receivable messages (hereinafter referred to as RCV) 8 are set,
Send to computer 2. On Computer 2, RE
Upon receiving Q6, the window size setting processing unit 4 sets its own maximum number of continuously transmittable messages (hereinafter referred to as SEN) 9 and R
Compare the numerical value with CV8, and compare the smaller numerical value with the window size (hereinafter referred to as WS) 1 in the computer 2.
Set as 0. Subsequently, the start notification response transmission processing unit 5
Sets the start notification response message type (hereinafter referred to as RSP-TYPE) 12 and the RCV 13 in the start notification message (hereinafter referred to as RSP) 11 and transmits the same to the computer 1. In the computer 1, the window size setting processing unit 4 receiving the RSP 11 compares the values of its own SEN 14 and RCV 13 with each other, and sets the smaller value as the window size (hereinafter referred to as WS) 15 in the computer 1. I do.

With this setting, all computers can perform data communication effectively utilizing the maximum number of continuously receivable messages determined by their own transmission / reception buffers.

[0013]

As described above, according to the present invention, each of a plurality of computers is activated when it is the originating station for data communication, and sets its own maximum number of continuously receivable messages at the start of data communication. The start notification transmission processing means for transmitting the start notification message is compared with the maximum number of continuously receivable messages included in the start notification message and the notification start response message transmitted by another computer and the maximum number of self-continuous receivable messages. A window size setting processing means for setting a smaller numerical value as its own window size, and upon receiving a start notification message transmitted by another computer, transmits a start notification response message in which the maximum number of continuously receivable messages is set. By including the start notification response transmission processing means, even if the size of the transmission and reception buffer is different between the calling side and the called side, It possible to specify a different window size in the called side and the called side, the effect exists that can be effectively utilized transmission and reception buffer, each of having.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a procedure of an incoming call receiving operation.

[Explanation of symbols]

 1, 2 Computer 3 Start notification transmission processing unit 4 Window size setting processing unit 5 Start notification response transmission processing unit 6 Start notification message (REQ) 7 Start notification message type (REQ-TYPE) 8, 13 Maximum number of continuously receivable messages ( RCV) 9, 14 Maximum number of messages that can be transmitted continuously (SEN) 10, 15 Window size (WS) 11 Start notification message (RSP) 12 Start notification response message type (RSP-TYPE)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04L 12/56 H04L 29/08

Claims (1)

(57) [Claims] In a window size negotiation system for adjusting an information amount of data communication performed between a plurality of computers constituting a communication network, each of the plurality of computers may be used as a transmitting station of the data communication. Start notification transmission processing means for starting and transmitting a start notification message in which the maximum number of continuous receivable messages is set at the start of the data communication, and a start notification message transmitted by another computer and a maximum included in the notification start response message. Window size setting processing means for comparing the size of the number of continuously receivable messages and the maximum number of messages that can be continuously transmitted and setting the smaller value as its own window size, and a start notification message transmitted by the other computer. Start notification response transmission processing that transmits a start notification response message that sets its own maximum number of continuously receivable messages when received Means for negotiating a window size.