JP2001333129A - Communication terminal and communication control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio equipment that can more effectively and simply utilize various methods developed to efficiently use the TCP, which is protocol having been substantially created at the supposition of use in a wired line, for a wireless line. SOLUTION: A radio terminal 100 informs a server 103 being a communication opposite party about a radio line number/option number to request a desired option via a radio base station 101 and a network 102. The server 103 refers to a correspondence table on the basis of the radio link number/option number to obtain concrete contents of parameter revision corresponding to the radio link number/option number. The server 103 checks whether or not the option with the obtained contents is available and informs the radio terminal 100 about the result. If the desired option is not available, the radio terminal 100 informs the server 103 about invalidation of the option request.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication terminal and a communication control method for performing data communication via a wireless link.

[0002]

2. Description of the Related Art TC is a transport layer protocol used for communication between terminals such as computers.
P (Transmission Control Pr)
otocol). TCP guarantees the transfer of packets transmitted and received between end terminals. On the other hand, it estimates the degree of congestion in the network and controls the packet transmission rate. This is generally called flow control or congestion control.

[0003] Flow control in TCP is called a sliding window method, in which packets can be transmitted and received for a window determined between transmission and reception. As a method for confirming the delivery of the packet, a cumulative delivery confirmation (cumulative ACK) is used.

[0004] Congestion control is slightly different depending on the TCP version, but fast retransmit and fast recovery (Fast retransmit).
An algorithm called "and fast recovery" is generally employed.

[0005] Furthermore, a fixed timer is applied to a transmitted packet to cope with a loss of delivery confirmation.

On the other hand, since the above algorithm alone cannot cope with all networks, an optional parameter change is also specified.

As described above, various mechanisms are employed in TCP in order to transfer packets more efficiently.

However, since TCP is designed for use in a high-speed and low-error-rate network such as a wired network, it is necessary to use TCP in a low-speed and high-error-rate link such as wireless. It is known that the throughput is reduced as described above.

[0009] For this purpose, each research institution has considered a method corresponding to them. These techniques are achieved by a combination of the above algorithm and its parameters, or the use of options.

[0010] One of these options is selective acknowledgment. This is a technique in which a method called a cumulative acknowledgment is used in TCP, but a selective acknowledgment can be selected by an option.

However, it has been pointed out that the selective acknowledgment option itself has a larger amount of information than the TCP header, and is inefficient on low-speed links such as radio.

Further, there is no mechanism capable of presenting a change of the above-mentioned algorithm or its parameter, and options must be presented one by one.

[0013]

As described above, TC
P (Transmission Control Pr)
When the data is transmitted over a wireless link by using the Internet protocol (autocol), the throughput is reduced more than necessary. Various methods have been proposed to solve this. However, the solution has caused a new problem, and there has been a problem that there is no easy way to use this.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a communication terminal capable of effectively using a wireless transfer control protocol originally intended for wired use. And a communication control method.

[0015]

SUMMARY OF THE INVENTION The present invention relates to a communication terminal for transmitting and receiving packets and communicating with another communication terminal.
A set of an option number indicating a change of one or more parameters in a protocol used in the communication and a radio link number indicating a type of one or more parameters to be changed,
Option processing means for giving a transmission packet to be transmitted, transmission means for transmitting the transmission packet to which the option number and the radio link number have been given by the option processing means to the other communication terminal, A receiving unit that receives a response packet from the other communication terminal; and a parameter processing unit that determines whether the parameter can be changed based on the received response packet.

According to the present invention, in a communication terminal that transmits and receives a packet and communicates with another communication terminal, the communication terminal may change one or more parameters in a protocol used in the communication from the other communication terminal. Receiving means for receiving a transmission packet to which a set of an option number indicating the option and a radio link number indicating a parameter type of one or more parameters to be changed; and
In the case where an option number indicating a change of one or more parameters is given, while determining the type of one or more parameters to be changed based on the radio link number given along with the transmission packet, Option processing means for determining whether or not the obtained parameter type can be applied at the own terminal, and transmission means for transmitting, to the other communication terminal, a response packet to which information indicating the result of the determination is added And characterized in that:

Also, the present invention provides a communication terminal for transmitting and receiving a packet and communicating with another communication terminal, for transmitting a packet having a packet header including a predetermined item to the other communication terminal, The content of the predetermined item;
A storage unit for storing information indicating the content and information having a smaller amount of information than the content in association with each other, and transmitting a packet having a packet header including the predetermined item, If the content of the predetermined item is not stored in the storage means, the content of the predetermined item is associated with information indicating the content and having an information amount smaller than the content, and stored in the storage means. When the content of the predetermined item is stored in the storage unit, the information stored in the storage unit in association with the content is added to the packet header in place of the content. And optional processing means.

According to the present invention, there is provided a communication terminal for relaying a packet transferred between one communication terminal and another communication terminal, wherein a packet having a packet header including a predetermined item is transmitted from the one communication terminal. And a packet having a packet header including the predetermined item,
Means for transmitting to the other communication terminal, and, for the one communication terminal, the contents of the predetermined item and the information indicating the contents and information having a smaller amount of information than the contents are stored in association with each other. A receiving unit that receives a packet having a packet header including the content of the predetermined item, the content of the predetermined item, and information indicating the content and having a smaller amount of information than the content. When a packet having a packet header to which the information is added is received instead of the content of the predetermined item, the information is stored in the storage unit in association with the information. And optional processing means for replacing the contents with the contents stored in the storage means in association with the information.

It should be noted that the present invention relating to the apparatus is also valid as an invention relating to a method, and the present invention relating to a method is also valid as an invention relating to an apparatus.

Further, the present invention relating to an apparatus or a method is provided for causing a computer to execute a procedure corresponding to the present invention (or for causing a computer to function as means corresponding to the present invention, or for causing a computer to correspond to the present invention). The present invention is also realized as a computer-readable recording medium in which a program for realizing the function of performing the above is recorded.

According to the present invention, it is possible to present a change in an algorithm and its parameters.

According to the present invention, options can be presented with a small amount of information.

According to the present invention, options can be presented collectively.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows an example of the overall configuration of a network system according to the present embodiment.

The wireless terminal 100 is connectable to the network 102 via the base station 101 by a wireless link, and is connected to the server terminal 10 connected to the network 102.
3 is communicable. Wireless terminal 100 and server terminal 1
03 may support multimedia for communicating voice, image, and data, for example. Note that another wireless terminal 100 may be connected to the base station 101, and another base station or server terminal may be connected to the network 102.

In the present embodiment, it is assumed that the correspondence between the radio link number and the protocol change content for the radio number is predetermined.

Further, in the present embodiment, as the option number in the TCP protocol, the correspondence between the above-mentioned predetermined radio link number and the content of the protocol change (FIG. 6)
Specific option number that indicates the use of this option.

FIG. 2 shows an example of the internal configuration of the wireless terminal 100.

[0030] As shown in FIG.
Is an option number holding table 2 for holding information related to the wireless link of the wireless terminal 100, the transmitting / receiving unit 200, the option processing unit 201, the protocol processing unit 202,
03 is included.

The radio terminal 100 can use all of the radio links of the above-mentioned predetermined radio link number,
In some cases, only some of them can be used.

The option number holding table 203 stores the radio link numbers of the radio links that can be used by the radio terminal 100 among the radio links of the predetermined radio link numbers, and the radio link currently used by the radio terminal 100. At least information indicating the wireless link number of the link is held. Alternatively, the above-mentioned predetermined wireless link number,
At least a flag indicating whether the wireless link number is usable in the wireless terminal 100 and a flag indicating whether the wireless link number is currently used in the wireless terminal 100 may be held. . In the option number holding table 203 of the wireless terminal 100 that can use only one wireless link number, the information indicating the currently used wireless link number or the flag indicating whether the wireless terminal 100 is currently used is omitted. Is also good.

The specific option number may be held in the option number holding table 203, or may be held by another part such as the option processing unit 201 or the protocol processing unit 202 (this embodiment). Let's take the former as an example.)

The correspondence (see FIG. 6) between the wireless link number and the protocol change content may be held in the option number holding table 203, or may be stored in the option processing unit 201 or the protocol processing unit 202. Part may have. Further, the correspondence between the wireless link number and the protocol change content is determined by the wireless terminal 1
00 may be provided only for usable wireless link numbers, or may be provided for all wireless link numbers including those that the wireless terminal 100 cannot use.

FIG. 3 shows an example of the internal configuration of the server terminal 103.

As shown in FIG. 3, the server terminal 10
Reference numeral 3 includes a transmission / reception unit 300, an option processing unit 301, a protocol processing unit 302, and a protocol option table 303 in which a correspondence between a wireless link number and a protocol change content is described.

It is assumed that the server terminal 103 has a correspondence relationship between the wireless link number and the protocol change content for all predetermined wireless link numbers.

FIG. 4 shows an example of a sequence for establishing a TCP connection.

The wireless terminal 100 starts an operation of establishing a TCP connection with the server terminal 103 in a sequence as shown in FIG.

More specifically, first, when the wireless terminal 100 sends out the TCP SYN packet 401, the protocol processing unit 202 asks the option processing unit 201 whether or not to perform an operation of adding an option to the TCP header. Contact Upon receiving the inquiry, the option processing unit 201 sets the option number holding table 203
The wireless link number of the wireless link currently used is obtained from the packet (the wireless link number currently used may be obtained from a portion other than the option number holding table 203), and the packet as shown in FIG. Answer as format (option number / wireless link number) option. Upon receiving the option, the protocol processing unit 202, as shown in FIG.
Option in the TCP header (first option)
To the server terminal 103 through the transmitting / receiving unit 200.
Send to. At the same time, the option processing unit 2
01 performs a parameter change to the protocol processing unit 202 according to the specification of the option.

The SYN packet 401 transmitted from the transmission / reception unit 200 of the wireless terminal 100 passes through the base station 101 and passes through the network 102 to the server terminal 10.
3 is received by the transmitting / receiving section 300.

When the protocol processing unit 302 of the server terminal 103 that has received the SYN packet 401 recognizes that an option (first option) is added to the TCP header, the protocol processing unit 302 cuts out the option and transmits it to the option processing unit 301. I do. Option processing unit 301
Understands that the option is an option corresponding to a specific radio link (that is, the option number is the specific option number described above), and based on the radio link number described in the option, The option information is acquired by referring to a protocol option table 303 that describes the correspondence between the wireless link number and option information indicating the specific content of the option. FIG. 6 shows an example of the protocol option table. The option processing unit 301 sorts specific options indicated by the obtained option information into those that can be performed by the terminal itself and those that cannot be performed. Then, as shown in FIG. 7, the result of this decision is arranged in a bit order in a predetermined order, and this data (in the example of FIG. 7, “0101000
0 "; in this example, 1 indicates that the requested option is possible, and 0 indicates that the requested option is not possible or is not the requested option). The response information is transmitted to the protocol processing unit 202. The protocol processing unit 3
02 adds the data as an option (second option) to the SYN / ACK packet 402 and transmits the data to the wireless terminal 100 through the transmission / reception unit 200. At the same time, the option processing unit 301 transmits a parameter change in accordance with the above-described option specification to the protocol processing unit 302.
Do for

If the option number added to the TCP header is not the above specific number but a normal number, the normal option processing corresponding to the number is performed.

SYN / ACK packet 402 transmitted from transmitting / receiving section 300 of server terminal 103 passes through base station 101 via network 102 and is received by transmitting / receiving section 200 of wireless terminal 100.

Upon receiving the SYN / ACK packet 402, the protocol processing unit 202 of the wireless terminal 100
The option (second option) added to the ACK packet 402 is transmitted to the option processing unit 201.
Upon receiving this option, the option processing unit 201
It is determined whether the option (first option) is to be enabled or disabled with reference to the result of whether or not this option indicates, and the determination result is transmitted to the protocol processing unit 202.

As a method of this determination, for example, there is the following method.

(First method) It is determined to be valid when all of the target options are possible, and to invalidate when some of the target options are not possible. (Second method) For each radio link number, mandatory options and non-essential options are defined, and this is valid when all mandatory options are possible, and is invalid even for some mandatory options. If there is, it is determined to invalidate. (Third method) For each wireless link number, a valid bit pattern (or its condition) as the answer information as shown in FIG. 7 is defined, and when the answer information matches the valid bit pattern (or It is determined to be valid when the condition is satisfied), and to be invalid in other cases.

To invalidate the option, use ACK4
03 invalid option (third option)
To the server terminal 103. When enabling the option, the ACK 403 is transmitted to the server terminal 103 (without adding the option).

When disabling the option,
Cancel the previous parameter change.

In the second method or the third method, when options are validated but some of the options are not used, the option that is not used is performed first. Canceled parameter change.

The invalid option (third option) may be in the middle of data transmission.

ACK 403 transmitted from transmitting / receiving section 200 of wireless terminal 100 passes through base station 101 and is received by transmitting / receiving section 300 of server terminal 103 via network 102.

Server terminal 10 receiving ACK 403
The third protocol processing unit 302 outputs an “invalid option” option (third option) to the ACK 403.
Check if is added. If added, parameter changes made according to the option specifications are returned to the default settings.

In the above description, when the wireless link is used, the above-described specific option number is used.
A flag indicating "whether or not to perform an operation to add an option to a TCP header" is provided in correspondence with a wireless link number, and the flag indicates that "the operation to add an option to a TCP header is not performed". For the number,
It is also possible to adopt a configuration in which an option with the specific option number is not added.

In the above description, the specific option number is described as the only one. However, a plurality of specific option numbers may be provided and used. in this case,
There are a method of providing a functional difference to a plurality of specific option numbers and a method of not providing a functional difference to a plurality of specific option numbers.

Also, a specific option number is provided for each radio link number. In FIG. 5, only a specific option number is used without using a radio link number. In FIG. 6, a specific option number is used instead of a radio link number. It is also possible to use it.

As described above, the properties of the radio link (for example,
If you want to add protocol options or change parameters for each wireless link based on whether or not errors are guaranteed in the wireless link, and the degree of guarantee, reduce the processing load by using a single option. Becomes possible.

(Second Embodiment) FIG. 8 shows an overall configuration example of a network system according to the present embodiment.

The wireless terminal 600 can be connected to the network 602 via the base station 601 and the wireless terminal device 605 by a wireless link, and can communicate with the server terminal 604 connected to the network 602 via the access server terminal 603. It is. The wireless terminal 600 and the server terminal 604 may support multimedia for communicating voice, image, and data, for example. In the present embodiment, the access server terminal 603 and the server terminal 604 may have normal functions. Access server terminal 603 and server terminal 604
For example, a public network or a local network may be used. Also,
Another wireless terminal 600 may be connected to the base station 601, another base station may be connected to the wireless terminal device 605, and another server may be connected to the access server terminal 603. A terminal may be connected, or a wireless terminal device, another base station, an access server terminal, or a server terminal may be connected to the network 602.

FIG. 9 shows an example of the internal configuration of wireless terminal 600.

As shown in FIG.
Includes a transmission / reception unit 700, an option processing unit 701, a protocol processing unit 702, and an option conversion table 703.

FIG. 10 shows an example of the internal configuration of the wireless terminal device 605.

As shown in FIG. 10, the wireless terminal device 6
Reference numeral 05 denotes a transmission / reception unit 800, an option processing unit 801, a protocol processing unit 802, and an option conversion table 803.
including. The option conversion table 803 is created when necessary for each wireless terminal, and is deleted after becoming unnecessary.

The operation of this embodiment will be described below.

The wireless terminal 600 establishes a connection with the server terminal 604 and establishes a PPP (Point-to-Point Protocol) with the wireless terminal device 605 after a wireless link with the base station 601 is established.
col) is established.

Thereafter, packets as shown in FIG. 4 are exchanged to establish a TCP connection. At this time, the wireless terminal 600 and the server terminal 604 transmit the maximum amount of data (hereinafter, referred to as the maximum window size; WS means the maximum window size) that can be received by one reception, in the TCP header shown in FIG. Window size field (16-bit window
size) and transmit. This window size can be increased by the window size option.

The SYN transmitted from wireless terminal 600
The packet 401 includes a SACK (S
selective ACK) option (the first 1 byte is an option number, and the next 1 byte is
e is the length of data such as a subsequent parameter (eg, by
te)). In response to the SACK option, the server terminal 604 returns an affirmative response as shown in FIG. 12 similarly in the optional part of the SYN / ACK 402 in FIG.

At this time, the wireless terminal 600 and the server terminal 604 determine from the maximum window size of the partner terminal that
Based on the following correspondence, it is determined that the SACK option field to be transmitted in the future has the following number of bytes. WS <256 → 1 byte 255 <WS <65536 → 2 bytes 65535 <WS <16777216 → 3 bytes 166677216 <WS → 4 bytes That effect can be expected.

With the above, a TCP session is established, and the wireless terminal 600 and the server terminal 604 are ready to transmit and receive data.

Here, the server terminal 604 transmits 15 packets having the following sequence numbers to the (access server terminal 603, the network 602, the wireless terminal device 60).
(5, via the base station 601). FIG. 13 shows the wireless terminal 600 and the server terminal 6 at this time.
4 shows an example of a packet transmission / reception sequence with the G.04.

Here, "3 to
The fifth case (902) and the tenth to twelfth cases (906) are lost on the way of the wireless link. "

First, the wireless terminal 600 transmits the first two packets (sequence numbers = 0 to 2000; 90 in the figure).
1) is received.

The third to fifth packets (902) are lost in the network.
0 is the sixth (sequence number = 5001 to 6000)
(903) is received. Here, the wireless terminal 6
The protocol processing device 702 in 00 recognizes that a packet loss has occurred, and transfers sequence number information indicating the sequence number of the lost packet (in this example, 2001 to 5000) to the option processing unit 701. .

Upon receiving the sequence number information, the option processing unit 701 refers to the option conversion table 703 and checks whether there is an entry having the sequence number of the lost packet (2001 to 5000 in this example). Here, the option conversion table 703
Does not have an entry with the same sequence number,
As shown in FIG. 14, the option processing unit 701 creates an item in the option conversion table 703 that holds sequence number information and a number corresponding to the sequence number information (hereinafter, referred to as a registration number).

It should be noted that the rule for issuing the registration number is as follows.
It is assumed that 0 is the same as the wireless terminal device 605 (in this example, the registration number is a consecutive number issued in order from 1).

Subsequently, the option processing unit 701 operates as shown in FIG.
5 is transmitted to the protocol processing unit 702, and the protocol processing unit 702
Returns an acknowledgment (907) with the option added to the server terminal 604 (via the base station 601 and the wireless terminal 605).

In the example of FIG. 15, the first part (5)
Is the option number, the next part (6) is the length of data such as the following parameters, the next part (2001) is the head number of the range of the sequence number of the lost packet, and the next part (5000) is the lost packet. At the end of the range of sequence numbers.

Upon receiving the acknowledgment (907), the protocol processing unit 802 in the wireless terminal device 605 recognizes that an option has been added, and transfers the option to the option processing unit 801. Option processing unit 80
2 creates an option conversion table 808 having items holding sequence number information and registration numbers corresponding thereto, as shown in FIG. Option processing unit 80
1 transmits the option conversion unnecessary information to the protocol processing unit 801 because option conversion is not necessary.

The protocol processing unit 801 of the wireless terminal device 605 receiving the option conversion unnecessary information transmits the acknowledgment (907) directly to the server terminal 604.

After the option conversion table as illustrated in FIG. 14 is shared between the wireless terminal 600 and the wireless terminal device 605 as described above, the information registered in the option conversion table is , From the wireless terminal 600 to the wireless terminal device 605, instead of the information,
By notifying the registration number corresponding to the information, the information can be transmitted (that is, the amount of information can be compressed and notified with a smaller amount of information).

Then, subsequently, the wireless terminal 600
Packets (904, 905) having sequence numbers of 1 to 9000 and 1200 to 15000 are received.

Protocol processing unit 70 in wireless terminal 600
When it is determined that a packet (906) having a sequence number of 8001 to 11000 has been lost, the second transmits information on the occurrence of the packet loss to the option processing unit 701 to create an option. The option processing unit 201 refers to the option conversion table 703, newly writes information of the lost packet (906) to the option table, and sets the number corresponding to the packet (902) that is a lost packet that has not been retransmitted yet. Take out. As for the packet which has transmitted the information indicating that the packet has already been lost using the information, an option in which the range of the sequence number of the lost packet is replaced with the registration number (= 1) as shown in FIG. As for the packet (906) that is added and new loss information, a normal option as shown in FIG. 16B (in this example, the start number of the sequence number range of the lost packet = 9001, the end number) = 12000) is created and added. The created option is stored in the protocol processing unit 7
02 is added to the confirmation response (908). The protocol processing unit 702 sends an acknowledgment (908) to the (base station 60
1. via the wireless terminator 605) server terminal 604
Send to.

In the example of FIG. 16A, the first part (6) has the option number, the next part (3) has the length of the data such as the following parameters, and the next part (1) has been lost. The registration number corresponds to the range of the packet sequence number. Also, whether the option number indicates the range of the sequence number or the corresponding registration number is identified based on the difference between the option numbers.

Upon receiving the confirmation response (908), the protocol processing unit 802 of the wireless terminal device 605 confirms that the option has been added, and transfers the option to the option processing unit 801. Option processing unit 801
Reads the option and registers it in the option conversion table 803 because the part shown in FIG. 16B is a new part. On the other hand, regarding the part of FIG. 16A, the option conversion table 803 is referred to and the corresponding number is re-created as an option as shown in FIG. 17 (in this example, the first of the lost packet sequence number is lost). Number = 2001, end number = 500
0, and the start number of the second range = 9001 and the end number = 12000), and transmit them to the protocol processing unit 802.

The protocol processing unit 8 of the wireless terminal device 605
02, the option is added back to the acknowledgment (908) and transmitted to the server terminal 604.

The server terminal 604 confirms the lost packets (902, 906) from the above two acknowledgments (907, 908) and retransmits them.

Next, a case where retransmission is successful and a case where a part of retransmission fails will be described.

(1) Case of Successful Retransmission The radio terminal 10 receiving the retransmitted packet (909)
The third protocol processing unit 602 transfers the sequence number information of the received packet to the option processing unit 601. The option processing unit 601 refers to the option conversion table 703 based on the sequence number information. If the sequence number of the retransmitted packet and the sequence number of the packet in the option conversion table 703 overlap, the option conversion unit 601 overlaps. Delete the item that is Subsequently, the option processing unit 701 transmits, to the protocol processing unit 702, no-option addition information indicating that no option is added.

The protocol processing unit 702 that has received the no-option-added information does not add any option but simply sends an acknowledgment (910) only (the base station 601 and the wireless terminal device 6).
(Via the server terminal 605).

Upon receiving the acknowledgment (910), the protocol processing unit 802 of the wireless terminal device 605 confirms that no option has been added.
01 is transmitted, and an acknowledgment (91
0) is transmitted to the server terminal 604.

The option processing unit 801 that has received the no-option additional information deletes the entry in the option conversion table 803.

(2) Case where a part of retransmission has failed Here, the packet (911) having a sequence number of 2001 to 3000 is lost again, and the other retransmission packets (912) are safely received by the wireless terminal 601. Shall be.

The protocol processing unit 702 of the wireless terminal 103 that has received the retransmitted packet (912) transfers the sequence number information of the received packet to the option processing unit 701. The option processing unit 701 refers to the option conversion table 703 based on the sequence number information and checks whether the sequence number of the retransmitted packet and the sequence number of the packet in the option conversion table 703 overlap. In this example, the first item is a sequence number 3001 to 400
Only the 0s overlap and the second item matches the entry. Therefore, as shown in FIG. 18, the option processing unit 701 deletes any of the items and newly sets the sequence numbers 2001 to 3000 as the third entry.
Is generated, an option as shown in FIG. 19 (in this example, the start number of the range of the sequence number of the lost packet = 2001, the end number =
3000) and sends it to the protocol processing unit 702.

Upon receiving the option information, the protocol processing unit 702 checks the acknowledgment (91
3) is transmitted to the server terminal 604 (via the base station 601 and the wireless terminal device 605).

The protocol processing unit 802 of the wireless terminal device 605 receiving the confirmation response (913) transmits the option information to the option processing unit 801. The option processing unit 801 is the option processing unit 70 of the wireless terminal 600.
Similarly to 1, based on the sequence number information of the option, the relation between the sequence number of the retransmitted packet and the sequence number of the packet in the option conversion table 703 is checked by referring to the option conversion table 803. In this example, only the sequence numbers 2001 to 3000 overlap in the first item, and the second item recognizes that the entry does not exist in the option, that is, that any of the items has changed. Therefore,
As shown in FIG. 18, the option processing unit 801 deletes any of the items and newly creates a third entry.
The information that the sequence numbers 2001 to 3000 are not received is created. Option processing unit 801
Transmits no option conversion unnecessary information to the protocol processing unit 801 because there is no need for option conversion.

The protocol processing unit 801 of the wireless terminal device 605 that has received the option conversion unnecessary information transmits the acknowledgment (913) to the server terminal 604 as it is.

In the above description, the rules for issuing registration numbers are the same for the wireless terminal 600 and the wireless terminal device 605, and the wireless terminal 600 and the wireless terminal device 605 issue numbers independently. The terminal 600 may issue a registration number and notify the wireless terminal device 605 of this.

In the above description, an example has been described in which the sequence number of a lost packet is described in the acknowledgment response when the sequence number is replaced (compressed) with a registration number. It is also possible to use an alternative configuration. Further, a configuration in which a plurality of types of information are replaced with registration numbers is also possible.

As described above, since the options can be compressed, the link can be used efficiently.

In the second embodiment, the case where the server terminal 604 is connected to the network 602 via the access server terminal 603 has been described as an example. However, as in the first embodiment, the server terminal 604 It is also possible to connect to the network 602 without going through the server terminal. Further, in the first embodiment, the case where the server terminal 103 is connected to the network 102 without using the access server terminal has been described as an example, but as in the second embodiment, the server terminal 10
3 is the network 102 via the access server terminal.
Is also possible.

The above functions can be realized as software. In addition, the present embodiment is a computer-readable computer that stores a program for causing a computer to execute predetermined means (or for causing a computer to function as predetermined means, or for causing a computer to realize predetermined functions). It can also be implemented as a recording medium.

Note that the configurations shown in the first and second embodiments are merely examples, and are not intended to exclude other configurations, and a part of the illustrated configuration is replaced by another. Other configurations obtained by replacement, omitting a part of the illustrated configuration, or adding another function to the illustrated configuration are also possible. In addition, the first embodiment and the second embodiment can be implemented in an appropriate combination.

The present invention is not limited to the above-described embodiments, but can be implemented with various modifications within the technical scope.

[0104]

According to the present invention, a transfer control protocol originally designed for use on a wire can be used on a wireless basis.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a network system according to a first embodiment of the present invention;

FIG. 2 is an exemplary view showing a configuration example of a wireless terminal according to the embodiment;

FIG. 3 is an exemplary view showing a configuration example of a server terminal according to the embodiment;

FIG. 4 is an exemplary view showing an example of a sequence for establishing a TCP connection in the embodiment.

FIG. 5 is a view showing an example of an optional packet format in the embodiment.

FIG. 6 is an exemplary view showing an example of a protocol option table according to the embodiment;

FIG. 7 is a view showing an example of an optional response format in the embodiment.

FIG. 8 is a diagram illustrating a configuration example of a network system according to a second embodiment of the present invention;

FIG. 9 is a diagram showing a configuration example of a wireless terminal according to the embodiment;

FIG. 10 is a diagram showing a configuration example of a wireless terminal device according to the embodiment;

FIG. 11 is a view showing an example of a TCP header in the embodiment.

FIG. 12 is an exemplary view showing an example of a request / positive format of a SACK option in the embodiment.

FIG. 13 is a view showing an example of a packet transmission / reception sequence in the embodiment.

FIG. 14 is a view showing an example of an option conversion table in the embodiment.

FIG. 15 is a view showing an example of an option format according to the embodiment;

FIG. 16 is an exemplary view showing an example of an option format in the embodiment.

FIG. 17 is an exemplary view showing an example of an option format in the embodiment.

FIG. 18 is a view showing an example of an option conversion table according to the embodiment;

FIG. 19 is an exemplary view showing an example of an option format in the embodiment.

[Explanation of symbols]

 100, 600: wireless terminal 101, 601: base station 102, 602: network 103, 604: server terminal 603 ... access server terminal 605: wireless terminal device 200, 300, 700, 800 ... transmitting / receiving unit 201, 301, 701, 801 ... Option processing units 202, 302, 702, 802 ... Protocol processing unit 203 ... Option number holding table 303 ... Protocol option table 703, 803 ... Option conversion table

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference) HH63 NN12 NN22 NN26

Claims (6)

[Claims] 1. A communication control method for transmitting and receiving a packet between a first communication terminal and a second communication terminal, wherein the first communication terminal uses the packet for transmission to and from the second communication terminal. Transmitting a transmission packet to which a set of an option number indicating a change of one or more parameters in the protocol to be changed and a radio link number indicating a type of the one or more parameters to be changed is provided, The communication terminal, when an option number indicating a change of the one or more parameters is given to the transmission packet received from the first communication terminal, a radio link number attached to the transmission packet The type of one or more parameters to be changed is determined based on the parameter, and it is determined whether or not the determined parameter type can be applied in the own terminal. A response packet to which information indicating the result of the determination is added is transmitted from the terminal to the first communication terminal, and the first communication terminal is added to the response packet received from the second communication terminal. And a parameter processing means for determining whether or not the parameter can be changed based on the result of the determination. 2. A communication terminal for transmitting and receiving a packet and communicating with another communication terminal, comprising: an option number indicating a change of one or more parameters in a protocol used in the communication; Pair with a wireless link number indicating the type of parameter
Option processing means for giving a transmission packet to be transmitted; and the transmission packet to which the option number and the radio link number are given by the option processing means,
Transmitting means for transmitting to the other communication terminal; receiving means for receiving a response packet to the transmission packet from the other communication terminal; and determining whether or not to change the parameter based on the received response packet. A communication terminal comprising: a parameter processing unit. 3. A communication terminal for transmitting and receiving a packet and communicating with another communication terminal, comprising: an option number indicating a change of one or more parameters in a protocol used in the communication from the other communication terminal; Receiving means for receiving a transmission packet to which a set of one or more parameters to be changed and a radio link number indicating a parameter type of the parameter is provided; and changing the one or more parameters to the received transmission packet. In the case where the option number shown is given, the type of one or more parameters to be changed is determined based on the wireless link number added together with the transmission packet, and the type of the determined parameter is determined. An optional processing unit that determines whether or not the application is applicable at the own terminal; and a response packet to which information indicating the result of the determination is added, Communication terminal comprising the transmission means for transmitting to another communication terminal. 4. A communication terminal for transmitting and receiving a packet and communicating with another communication terminal, wherein: a transmission means for transmitting a packet having a packet header including a predetermined item to the other communication terminal; Storage means for associating the content of the information with information indicating the content and information having a smaller amount of information than the content, and when transmitting a packet having a packet header including the predetermined item, When the content of the predetermined item is not stored in the storage means, the content of the predetermined item is associated with information indicating the content and having a smaller amount of information than the content. When the content of the predetermined item is stored in the storage unit and the content of the predetermined item is stored in the storage unit, the information stored in the storage unit in association with the content is replaced with the information instead of the content. Attached to packet header Communication terminal, characterized in that a option processing means for. 5. A communication terminal for relaying a packet transferred between one communication terminal and another communication terminal, comprising: means for receiving a packet having a packet header including a predetermined item from the one communication terminal. Means for transmitting a packet having a packet header including the predetermined item to the other communication terminal; and for the one communication terminal, contents of the predetermined item, and information indicating the contents; Storage means for storing information having a smaller amount of information in association with the content; and when receiving a packet having a packet header including the content of the predetermined item, the content of the predetermined item; Is stored in the storage unit in association with information indicating a smaller amount of information than the content, and the packet is added to the packet to which the information is added instead of the content of the predetermined item. Option receiving means for replacing the information with the contents stored in the storage means in association with the information before transmitting the packet when the packet having the header is received. A communication terminal characterized by the above-mentioned. 6. A communication terminal for transmitting and receiving a packet and communicating with another communication terminal, wherein the receiving means receives a packet having a packet header including a first item and a second item from the other communication terminal. A communication terminal comprising: an option processing unit that determines an information length of the first item based on the content of the second item added to a packet header of the received packet. .