JP2001245016A - Reliable method for data transfer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish efficient transmission by preventing useless retransmission in a communication system in which a transaction type protocol is adopted. SOLUTION: Two types of ACK messages are defined as an ACK message to a transaction starter. One is an S-ACK message showing the reception of a start message and the other is a U-ACK message showing that there is a response from a responder to the start message. The starter can obtain round trip time that does not depend on a processing speed or an external network factor in the responder side in such a manner that the responder returns the S-ACK message to the starter just after receiving the start message. By doing that, an accurate timer value can be set in a retransmission timer on the starter side and the useless retransmission of the start message can also be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a communication system employing a transaction-type protocol to ensure reliability in data transmission.

[0002]

2. Description of the Related Art For example, as a communication system of this type, a WAP (Wireless Application Protocol) has conventionally been used.
There are known systems that operate according to: WAP is
It is an open protocol suite that is defined as a communication protocol for the Web for cellular phones and PDAs.

[0003] In WAP, a protocol relating to the reliability of data transmission is a WSP (Wireless Session Protocol).
l) and WTP (Wireless Transaction Protocol)
These are the HTs in the TCP / IP stack
It corresponds to TP. Among them, WTP provides reliable data transfer based on a request / reply paradigm. Specifically, WTP supports retransmission of lost packets, selective retransmission and flow control, not using explicit connections,
It stipulates that an acknowledgment for a message be held.

[0004] An outline of a network configuration related to WAP is shown in FIG. When a server that supplies content (hereinafter, referred to as an origin server) exists on a WAP network, a WAP terminal (hereinafter, referred to as a WAP client) owned by a user directly communicates with the origin server according to WAP. Communicate with each other. On the other hand, if the origin server exists on another network, the WAP client communicates indirectly with the origin server via a WAP gateway / proxy.
Another network is, for example, the Internet,
Another protocol is the TCP / IP stack. In this case, the WAP gateway / proxy converts the content in the HTML format into the content in the WML format, and also converts the protocol from WTP or WSP to HTTP.

[0005] There are two transactions of class 1 and class 2 in the communication procedure according to WTP. Class 1 transactions provide a reliable start message transfer, while class 2 transactions provide a reliable start message transfer with a result message. Schematically, in both the class 1 transaction and the class 2 transaction, when the initiator sends a message (start message) indicating the start of communication to the responder, the responder responds to the start message with an acknowledgment (hereinafter simply ACK and ACK). ) To the initiator. Note that the initiator also starts the retransmission timer when transmitting the start message. If the retransmission timer times out before receiving an ACK, the initiator sends a start message again to the responder.

In the network shown in FIG.
The initiator is a WAP client. Respondents, on the other hand,
In the case of direct communication, it is an origin server, and in the case of indirect communication, it is a WAP gateway / proxy. In the following, the real /
A virtual device will be described as a corresponding layer device. That is, the real / virtual device of the X layer is referred to as the X layer device.

[0007] In a class 2 transaction, when the responding communication processing layer device receives a start message, the upper layer device generates a start response and a result request. When the responder is a proxy or a gateway, the upper layer device may connect to an external network or the like in response to the start message. For example, W
In the AP stack, the upper layer is a WSP layer, and the communication processing layer is a WTP layer.

More specifically, as shown in FIG. 13, upon receiving a start message from the communication processing layer device of the initiator, the communication processing layer device of the responder does not immediately transmit ACK for receiving the start message, Start the hold timer and wait for a certain time. If a start response is returned from the upper layer device during this standby, the communication processing layer device
The hold timer is started again to enter the standby state again. If the result request is supplied from the upper layer device before the set time elapses, the communication processing layer device sets the AC
Send a result message without sending K. The communication processing layer device of the initiator regards the result message as ACK. That is, on the initiator side, receiving this result message is regarded as receiving the ACK.

On the other hand, when the waiting time elapses in a state where neither the start response nor the result request is supplied from the upper layer device, the communication processing layer device of the responder, as shown in FIG. An ACK is returned to the initiator's communication processing layer device. This is done in order to prevent this retransmission because the initiator's communication processing layer device retransmits the start message when the retransmission timer activated by the initiator's communication processing layer device when the start message is sent out times out. Will be

In a class 1 transaction, the responding communication processing layer device activates a hold timer when receiving a start message and waits for a certain period of time, as shown in FIG. When the start response is received from the upper layer device during the standby, the responder's communication processing layer device returns an ACK to the initiator's communication processing layer device at that time. When the waiting time has elapsed without returning a start response from the upper layer device, the communication processing layer device on the responder side, as shown in FIG.
The CK is returned to the communication processing layer device on the initiator side. Through such a procedure, the number of messages sent to the transmission path can be reduced.

However, in both the class 1 transaction and the class 2 transaction described above, there may be a case where a synchronization shift occurs between upper layer devices. Here, the synchronization means that the upper layer device of the initiator and the upper layer device of the responder mutually grasp the state of the partner device and manage the state of the own device. That is, it means that the state of the upper layer device of the initiator and the state of the upper layer device of the responder match.

Taking a class 1 transaction as an example,
With reference to FIG. 17, a case where a synchronization shift occurs will be described.

As mentioned above, in WTP, the communication processing layer device of the responder activates the hold timer. If the start response is not returned before the timer expires, the responder's communication processing layer device transmits ACK to the initiator's communication processing layer device. Receiving ACK on the initiator side indicates that an acknowledgment has been received for the start message. Therefore, the initiator's upper layer device regards that there was a response from the responder's upper layer device. However, in reality, since there is no response from the upper layer device of the responder, a synchronization shift occurs between the upper layer devices.

In order to avoid such a synchronization shift, W
The TP has a function called User Acknowledgement as an option. When this function is adopted, the communication processing layer device of the receiver (ie, the responder) receiving the start message from the communication processing layer device of the initiator waits until the start response is returned from the upper layer device of the responder. Keep doing. In other words, when this function is used, even if the hold timer activated when the start message is received expires, if the start response is not supplied from the upper layer device, the responding communication processing layer device starts ACK. Is not sent to the communication processing layer device of the user.

For example, in class 1, the responder's communication processing layer device returns an ACK to the initiator's communication processing layer device upon receiving a start response from the upper layer device as shown in FIG. .

In class 2, the responding communication processing layer device restarts the hold timer upon receiving a start response from the upper layer device. After that, processing is performed in the same manner as the above-described procedure. That is, as shown in FIG. 19, when the result message can be returned before the waiting time elapses, the communication processing layer device of the responder sends the result message without sending ACK. on the other hand,
If the waiting time elapses without a result request being served,
As shown in FIG. 20, the communication processing layer device of the responder sends an ACK when the waiting time elapses.

Therefore, the upper layer device of the initiator only transmits when the upper layer device of the responder has sent a start response.
Receive notification of start confirmation. Thereby, the synchronization between the two is confirmed.

[0018]

SUMMARY OF THE INVENTION However, User A
The synchronization establishment method to which the acknowledgment is applied has a problem that when the round trip time as seen from the initiator greatly varies, a situation in which the communication processing layer device of the initiator performs unnecessary retransmission easily occurs. Here, the round trip time indicates a time from when a certain message is sent to when a response to the message is returned. That is, in the above case, the round trip time is the time from the transmission of the start message to the reception of the ACK.

This round trip time is preferably measured as the time required for round-trip transmission. That is, it is desired that the message be transmitted by the sender and then be received by the receiver and immediately return an ACK to the sender.

However, when the user acknowledgment function is applied, the timing of ACK output greatly differs depending on the timing at which the upper layer device of the responder outputs a start response or a result request. This is largely affected by application processing in the upper layer of the responder. In particular, if the responder is a WAP gateway / proxy and attempts to connect to an external network in response to the start message, the external network conditions will affect the response and the generation of results. As a result, the round trip time includes many factors other than the transmission delay.

Therefore, it becomes difficult for the initiator to appropriately set the retransmission timer. If a fixed time is set in the retransmission timer, it cannot clearly cope with a change in the round trip time. Even when the retransmission timer is set so as to adaptively change the actual round trip time measurement value, it is difficult to adapt to a large variation in round trip time. As a result, the initiator will resend the message even though the responder has received the initiation message. Such retransmission is useless.

Referring to FIGS. 21 to 23, the case where unnecessary retransmission occurs will be specifically described.

The communication processing layer device of the initiator assumes a loss of a message due to a transmission error or the like and starts a retransmission timer at the same time as transmitting the start message. Thereafter, if an ACK is not returned before the timer expires, the communication processing layer device determines that a message is lost and retransmits the same start message as shown in FIG. FIG. 21 shows the User Acknowledgeme
This shows a class 1 transaction using nt.

On the other hand, as described above, the User Acknowledge
When ment is set, the communication processing layer device of the responder continues to wait without sending ACK until receiving a response from the upper layer device. Therefore, if it takes a long time to supply a response from the upper layer device of the responder, the communication processing layer device of the responder cannot easily transmit ACK. In this case, the initiator's communication processing layer device may retransmit the start message. In summary, even though the start message has been received at the responder's communication layer device, the initiator's communication layer device assumes that the start message did not reach the responder and resends the start message. Eggplant As described above, there is a possibility that transmission resources are wasted.

In the class 2 transaction with user acknowledgment, the start message may be retransmitted as in the case of the class 1 transaction described above. As described above, in the class 1 transaction (data transmission + ACK), the supply of the start response from the responder's upper layer device causes the responder's communication processing layer device to immediately send an ACK to the initiator's communication processing layer device. Send. In a class 2 transaction (data transmission (request) + result transmission + ACK), upon receiving a start response from the upper layer device, the communication processing layer device activates a hold timer. As shown in FIG. 22, if a result request is issued before the hold timer expires, the responder's communication processing layer device sends only the result message to the initiator's communication processing layer device. Otherwise,
As shown in FIG. 23, an ACK is sent when a timeout occurs, and a result message is sent when a result is supplied.

As described above, in a transaction using User Acknowledgement, there is a possibility that the start message is retransmitted. Specifically, even if the value of the hold timer is set to a value that does not cause the communication processing layer device of the initiator to retransmit, the hold timer is activated after the start response is supplied from the upper layer device. , The possibility of retransmission increases.

It is an object of the present invention to achieve efficient transmission by preventing useless retransmission.

It is another object of the present invention to provide a communication system in which synchronization does not occur between upper layer devices.

[0029]

According to one aspect of the invention, an initiator device has a first communication processing layer device and a first upper layer device, and a responder device is a second communication processing layer device. And a second upper layer device, wherein a reliable data transfer method between said initiator device and said responder device is obtained. The reliable data transfer method includes a step of supplying a start request from the first upper layer device to the first communication processing layer device, and a step of transmitting the start request from the first communication processing layer device supplied with the start request. Transmitting a start message to a second communication processing layer device; and notifying a start instruction corresponding to the start message from the second communication processing layer device having received the start message to the second upper layer device. And transmitting a first acknowledgment message from the second communication processing layer device to the first communication processing layer device, indicating that the second communication processing layer device itself has received the start message. And the second upper layer device sends a start response corresponding to the start message to the second communication processing layer device. Transmitting a second acknowledgment message from the second communication processing layer device to the first communication processing layer device, indicating that the second upper layer device has responded to the start instruction. Transmitting a result message from the second communication processing layer device to the first communication processing layer device indicating that the request has been supplied to the second communication processing layer device.

The transfer of the first acknowledgment message from the responder to the initiator immediately after the reception of the start message allows the initiator to perform the preferred round trip without depending on the processing speed on the responder side or external network factors. You can get time. As a result, an accurate timer value can be set for the retransmission timer on the initiator side, and useless retransmission of the start message is prevented.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a communication system according to an embodiment of the present invention and its operation will be described in detail with reference to the drawings.

(First Embodiment) As shown in FIG. 1, a communication system according to a first embodiment of the present invention includes an initiator apparatus 1 and a responder apparatus 2. The initiator device 1
For example, it is a WAP client in a WAP network, and performs transmission processing using a start request generated by an upper layer device included therein, ie, an application or the like, as a start message. The responder device 2 is, for example, W
An origin server or a WAP gateway / proxy that operates according to the AP, receives a start message from the initiator device 1, and returns a response to the request and a result.

Referring to FIG. 1, an initiator apparatus 1 includes an upper layer device 11, a start request processing unit 12, a timer 13
A storage unit 14, a retransmission processing unit 15, a message transmission / reception device 16, a start confirmation / result instruction processing unit 17,
And a result response processing unit 18. Among them, the start request processing unit 12, the timer 13, the storage unit 14, the retransmission processing unit 15, the start confirmation / result instruction processing unit 17, and the result response processing unit 18 are communication processing layer devices on the initiator side. Is configured. The upper layer and the communication processing layer are, for example, WA
It corresponds to the WSP layer and the WTP layer in the P stack.
Examples of the message transmitting / receiving device 16 include a TCP layer device or a UDP layer device.

In this embodiment, the upper layer device 1
1 can correspond to at least one application service. The upper layer device 11 sends the communication start request generated there to the start request processing unit 12, and receives a confirmation and a result for the request from the start confirmation / result instruction processing unit 17. When receiving the result instruction, the upper layer device 11 supplies a result response to the result response processing unit 18 in order to transmit a result ACK message.

The start request processing unit 12 is a
In order to transmit the start request given from 1 to the responder apparatus 2, the start request is sent to the message transmitting / receiving device as a start message. In addition, the start request processing unit 12
It is determined whether the start request also requests notification of the result from the responder device, and the determination result is notified to the start confirmation / result instruction processing unit 17. At the same time, the same start message is stored in the storage unit 14 and the timer 13 is started. The timer 13 is started by the start request processing unit 12, and notifies the retransmission processing unit 15 that the time is up when a predetermined time elapses. That is, the timer 13 is a retransmission timer.

In the present embodiment, the storage unit 14 is used to store a start message as described above. In addition, in response to a request from the retransmission processing unit 15, the stored start message is supplied to the retransmission processing unit 15. Upon being notified by the timer 13 that the predetermined time has elapsed, the retransmission processing unit 15 retrieves the start message stored in the storage unit 14 from the storage unit 14 when the timer 13 is started, and transmits and receives the message. Device 16
And the timer 13 is started again.

The message transmitting / receiving device 16 includes the start request processing unit 12, the retransmission processing unit 15, and the result response processing unit 1.
8. The message such as the start message given from 8.
A corresponding data signal is processed and the data signal is transmitted to the responder apparatus 2. Further, the message transmitting / receiving device 16 processes the data signal received from the responder apparatus into a message format, and confirms the start of the message.
The result is sent to the result instruction processing unit 17. The start confirmation / result instruction processing unit 17 processes the message given from the message transmission / reception device 16, sends a start confirmation and a result response to the upper layer device 11, and stops the timer 13. Depending on the type of the message, the contents to be notified to the upper layer device 11 may be different, or nothing may be notified to the upper layer device 11. The result response processing unit 18 converts the result response given from the upper layer device 11 into a result ACK.
The message is transmitted to the message transmitting / receiving device 16 as a message. The message transmitting / receiving device 16 converts the result ACK message into a corresponding data signal, and transmits the converted data signal to the responder apparatus 2.

Referring again to FIG. 1, the responder device 2 comprises:
An upper layer device 201, a start instruction processing unit 202, a start response processing unit 203, a result request processing unit 204, a result confirmation processing unit 205, an S-ACK transmission processing unit 206,
U-ACK transmission processing section 207 and result transmission processing section 208
, A timer 209, a storage unit 210, a result retransmission processing unit 211, and a message transmission / reception device 212. Among them, a start instruction processing unit 202, a start response processing unit 203, a result request processing unit 204, a result confirmation processing unit 205, an S-ACK transmission processing unit 206, a U-ACK
The transmission processing unit 207, the result transmission processing unit 208, the timer 209, the storage unit 210, and the result retransmission processing unit 211
Configure the communication processing layer device on the responder side. On the responder side, the upper layer and the communication processing layer correspond to, for example, the WSP layer and the WTP layer in the WAP stack. Examples of the message transmitting / receiving device 212 include a TCP layer device and a UDP layer device.

The upper layer device 201 can at least partially correspond to the service provided by the upper layer device 11 on the initiator side. The upper layer device 201 processes the start instruction notified from the start instruction processing unit 202, and generates a start response and a result request to the start instruction. The generated start response is output to the start response processing unit 203, and the generated result request is output to the result request processing unit 204.
Is output to In order to obtain a response and a result to the instruction from the initiator apparatus 1, the upper layer device 201 may perform communication with another network, perform application processing, and the like.

The start instruction processing unit 202 receives a start message from the initiator apparatus 1 via the message transmission / reception device 212 and notifies the upper layer device 201 of the start instruction. At this time, the start instruction processing unit 202 according to the present embodiment requests the S-ACK transmission processing unit 206 to return an S-ACK message indicating reception of the start message to the initiator device 1. . When the start response processing unit 203 is supplied with the start response from the upper layer device 201, the start response processing unit 203 sends a U-ACK indicating that there is a response to the start message from the upper layer device 201 to the U-ACK transmission processing unit 207. Request to return to initiator device 1.

When a result request is supplied from the upper layer device 201, the result request processing unit 204 notifies the result transmission processing unit 208 of the supplied result request as a result message. The result confirmation process 205 includes a result ACK message transmitted from the initiator corresponding to the result message,
It is assumed that the result is received via the message transmitting / receiving device 212 and the result confirmation is notified to the upper layer device 201. At the same time, the timer 209 started by the result transmission processing unit 208 is stopped as described later. S-ACK transmission processing section 206
Responds to a request from the start instruction processing unit 202,
A CK message is generated, and the S-ACK message is sent to the message transmitting / receiving device 212.

The U-ACK transmission processing section 207 generates a U-ACK message in response to a request from the start response processing section 202, and sends the generated U-ACK message to the message transmitting / receiving device 212. The result transmission processing unit 208 sends the result message provided from the result request processing unit 204 to the message transmitting / receiving device 212, and causes the message transmitting / receiving device 212 to transmit the result message to the initiator apparatus 1. At this time, the result transmission processing unit 208 stores the same result message in the storage unit 210 and starts the timer 209. Timer 209
Is activated by the result transmission processing unit 208, and when the predetermined time elapses, notifies the result retransmission processing unit 211 that the time is up. That is, the timer 209
Operates as a retransmission timer on the responder side.

The storage section 210 stores the result message provided from the result transmission processing section 208, and delivers the result message to the result retransmission processing section in response to a request from the result retransmission processing section 211. When the timer 209 notifies that the predetermined time has elapsed since the transmission of the result message, the result retransmission processing unit 211
And sends the result message to the message sending / receiving device 212.

The message transmitting / receiving device 212 processes the data signal received from the message transmitting / receiving device 16 on the initiator side into a message format, and sends the message to the start instruction processing unit 202 and the result confirmation processing unit 205. The message transmitting / receiving device 213 converts a message provided from the S-ACK transmission processing unit 206, the U-ACK transmission processing unit 207, the result transmission processing unit 208, or the result retransmission processing unit 211 into a data signal, and converts the converted data signal. Is transmitted to the initiator apparatus 1.

Here, the operation of the communication system according to the first embodiment will be described in detail with reference to FIGS. FIG. 2 shows a protocol exchange according to the present embodiment. FIG. 3 is a flowchart showing the operation of the initiator apparatus 1, and FIG. 4 is a flowchart showing the operation of the responder apparatus 2.

First, the operation of the initiator apparatus 1 will be described. The communication start request generated by the upper layer device 11 is supplied to the start request processing unit 12. The start request processing unit 12 generates a start message to be transmitted to the responder device 2. After that, the start request processing unit 12 gives the start message to the message transmitting / receiving device 16, activates the timer 13, and stores the start message in the storage unit 14 (see step A1). Here, in the present embodiment, the activation of the timer and the stored message are always associated with each other. This is because a retransmission process is performed when the timer 13 times out, and an appropriate start message is retransmitted in the retransmission process.

When the start message is supplied, the message transmitting / receiving device 16 performs, for example, path control, link control, modulation, and the like, and transmits the start message to the responder apparatus 2 (see step A2). Thereafter, the initiator apparatus 1 enters an event waiting state (see step A3).

When the initiator apparatus 1 detects an event,
It operates according to the detected event (step A4).
reference).

If the detected event is a time-up in the timer 13, the retransmission processing unit 15 obtains a start message corresponding to the time measurement from the storage unit 14, and sends the start message to the responder device via the message transmitting / receiving device 16. 2 and resend the start message. At the same time, the retransmission processing unit 15 restarts the timer 13 (Step A).
5). By setting the maximum number of times or the maximum time for this retransmission, retransmission can be prevented from being repeated indefinitely.

If the detected event is the reception of an ACK message, the start confirmation / result instruction processing unit 17 stops the timer 13 (see step A6), and determines whether the received ACK message is a U-ACK or S-ACK. Is determined (see step A7). As a result of the determination, the received A
If the CK message is an S-ACK message,
The start confirmation / result instruction processing unit 17 does not notify the upper layer device 11 of the reception of the ACK message, and the initiator apparatus 1 returns to the event waiting state again. On the other hand, if the received ACK message is a U-ACK message, the start confirmation / result instruction processing unit 17 notifies the upper layer device 11 of the start confirmation (see step A8). Further, the start confirmation / result instruction processing unit 17 determines whether or not the previously transmitted start message also requests the responder apparatus 2 for a result message (step A9).
reference). As a result of the determination, if there is a possibility that the result message may reach the initiator device 1, the initiator device 1 enters the event waiting state again, or otherwise ends the data transfer process.

When the detected event is the reception of the result message, the start confirmation / result instruction processing unit 17 stops the timer 13 if the timer 13 is operating (see step A10). Then, the start confirmation / result instruction processing unit 17 notifies the upper layer device 11 of the result instruction (see step A11). When the upper layer device 11 outputs a result response, the result response processing unit 18 returns a result ACK message to the responder apparatus 2 via the message transmitting / receiving device 16 (see step A12), and performs the data transfer process. To end. Here, in the present embodiment, when the result message is received, the U-ACK is still received.
When the message has not been received, the start confirmation / result instruction processing unit 17 performs the start confirmation on the upper layer device 1.
Notify 1.

Next, the operation of the responder apparatus 2 will be described. When the responder apparatus 2 receives the start message (see step B1), the start instruction processing unit 202 notifies the upper layer device 201 of the start instruction, and the S-ACK transmission processing unit 206 transmits the message via the message transmission / reception device 212. ,
An S-ACK message is returned to the initiator device 1 (see step B2). Thereafter, the responder apparatus 2 enters an event waiting state. In the present embodiment, events that may occur after this are the supply of a start response by the upper layer device 201, the supply of a result request by the upper layer device 201, the expiration of the timer 209, and the result ACK message from the initiator apparatus 1. Receiving.

When the responder apparatus 2 detects the event,
It operates according to the detected event (step B4).
reference).

If the detected event is the supply of a start response, the start response processing unit 203 notifies the U-ACK transmission processing unit 207 of the detection of the event. U-
In response to this notification, the ACK transmission processing unit 207 returns a U-ACK message to the initiator device 1 via the message transmitting / receiving device 212 (step B5).
reference). Here, the responder apparatus 2 determines whether or not the supply of the result request continues, for example, as in a WTP class 2 transaction (see step B6). If it is determined that a result message may be transmitted, the responder apparatus 2 enters an event waiting state. On the other hand, if there is no possibility, the responder apparatus 2 ends the data transfer process.

When the detected event is the supply of the result request, the result request processing unit 204 notifies the result transmission processing unit 208 of the detection of the event. In response to the notification, the result transmission processing unit 208 sends a result message,
Activation of timer 209, storage unit 210 of the result message
Is executed (see step B7). That is,
In the present embodiment, if the result request is supplied before the start response is supplied from the upper layer device 201, U
-A result message is sent without sending an ACK (User Acknowledgement) message.

The retransmission of the result message is performed according to the same procedure as the retransmission of the start message in the initiator apparatus 1. That is, when the timer 209 times out,
The result retransmission processing unit 211 retransmits the result message to the initiator device 1 and restarts the timer 209 (see step B7). Here, the saving of the result message is included in step B7, but the saving of the result message may not be performed in the time-up process.

If the detected event is the reception of the result ACK message from the initiator apparatus 1, the result confirmation processing unit 205 stops the timer 209 (step B8).
reference). Then, the responder apparatus 2 ends the data transfer process.

In the above-described first embodiment, as the ACK message for the transaction initiator, an S-ACK message indicating reception of the start message and a U-ACK message indicating that the responder has responded to the start message. ACK messages were defined. Immediately after receiving the start message,
When the responder returns the S-ACK message to the initiator, the initiator can obtain a round trip time independent of the processing speed on the responder side and external network factors. This makes it possible to set an appropriate timer value for the retransmission timer on the initiator side, and to prevent useless retransmission of the start message. Furthermore, the function of the U-ACK message enables synchronization of the upper layer device of the responder and the upper layer device of the initiator.

Note that the wording used in the first embodiment is annotated. In the above embodiment, "request", "instruction", "response" and "confirmation" following "start" and "result" are services exchanged between the communication processing layer device and the upper layer device. Indicates a primitive. Since the "start" service is started from the initiator and the "result" service is started from the responder, they are described as "start request" and "result request", respectively.

More specifically, the start request indicates a request that the upper layer device of the initiator transmits a specific PDU (Protocol Data Unit) to a specific destination. At this time, an identifier is used to identify a series of transactions started from the start request from other transactions. The receiver sets the identifier when receiving the start message. Since these identifiers are used locally, the sender and receiver hold them separately.

The result request indicates, using the identifier set when the start message was received, a request to transmit a PDU for the result in the transaction corresponding to the identifier. In short, a request is simply a request for transmission of a PDU. Considering the meaning in the upper layer such as the application layer, the PDU of the start request includes the meaning "I want to transfer a file in a certain URL (Uniform Resource Locator)". Also,
"OK" is entered in the corresponding start response, and the file corresponding to the URL is entered in the PDU of the corresponding result request. Here, the URL is a notation method for uniquely specifying a storage location of an information resource such as a file distributed on the Internet. These service primitives exchanged between the communication processing layer and the upper layer are the same in other embodiments described later.

(Second Embodiment) Next, a communication system according to a second embodiment of the present invention will be described. In the communication system according to the present embodiment, the initiator device is the same as that according to the above-described first embodiment. On the other hand, as shown in FIG. 5, the responder apparatus 3 according to the present embodiment has the configuration of the responder apparatus 2 shown in FIG.
Further, a message holding unit 213 is provided.

That is, in the present embodiment, the start instruction processing unit 202, the start response processing unit 203, the result request processing unit 204, the result confirmation processing unit 205, the S-AC
K transmission processing section 206 and U-ACK transmission processing section 207
The result transmission processing unit 208, the timer 209, the storage unit 210, the result retransmission processing unit 211, and the message holding unit 213 constitute a communication processing layer device on the responder side. The upper layer and the communication processing layer are, for example, WAP
It corresponds to the WSP layer and the WTP layer in the stack. Examples of the message transmitting / receiving device 212 include a TCP layer device or a UDP layer device.

In the present embodiment, message holding section 213 is notified from start instruction processing section 202 as to whether or not the start message transmitted from initiator apparatus 1 also prompts the transmission of a result message. . The message holding unit 213 is supplied with an ACK message and a request to send a result message from the start response processing unit 203 and the result request processing unit 204. If there is a possibility that a result message may be sent out according to the notification from the start instruction processing unit 202, the message holding unit 213 receives the U-ACK message even if it receives a U-ACK message sending request from the start response processing unit 203. No transmission request is sent to the ACK transmission processing unit 207. Then, the message holding unit 213 waits until receiving a result message transmission request from the result request processing unit 204. Then, upon receiving the transmission request from the result request processing unit 204, the message holding unit 213 prompts only the result transmission processing unit 208 to transmit only the result message (see FIG. 6).

Here, the operation of the communication system according to the second embodiment will be described in detail with reference to FIGS. FIG. 6 shows a protocol exchange according to the present embodiment. FIG. 7 is a flowchart illustrating the operation of the responder apparatus 3. Since the operation of the initiator apparatus 1 is the same as that of the first embodiment, the description thereof is omitted.

When the responder apparatus 3 receives the start message (see step B1), the start instruction processing unit 202 notifies the upper layer device 201 of the start instruction, and the S-ACK transmission processing unit 206 sends the message transmission / reception device 212 , An S-ACK message is returned to the initiator apparatus 1 via the server (see step B2). Then, the responder device 3
Enters the event waiting state. In the present embodiment, events that may occur after this are the supply of a start response by the upper layer device 201, the supply of a result request by the upper layer device 201, the expiration of the timer 209, and the result ACK message from the initiator apparatus 1. Receiving.

When the responder apparatus 3 detects the event,
It operates according to the detected event (step B4).
reference).

Here, if the detected event is the supply of a start response, in the above-described first embodiment,
The U-ACK message was immediately returned. In the present embodiment, when a start response is supplied via the start response processing unit 203, the message holding unit 213 selects the next process according to the determination of the start instruction processing unit 202 (see step B9). . If there is no possibility that the result message is transmitted, the message holding unit 213
Causes the U-ACK transmission processing unit 207 to transmit a U-ACK message to the initiator device (see step B10). U-ACK transmission processing section 207 transmits U-AC
After transmitting the K message, the responder apparatus 3 ends the data transfer process. On the other hand, if there is a possibility that the result message will be transmitted,
-Notify anything to the ACK transmission processing unit 207. As a result, the U-ACK message is not transmitted, and the responder apparatus 3 enters an event waiting state.

If the detected event is the supply of a result request, the result request processing unit 204 notifies the result transmission processing unit 208 of the detection of the event. In response to the notification, the result transmission processing unit 208 sends a result message,
Activation of timer 209, storage unit 210 of the result message
Is executed (see step B7). As described above, if there is a possibility that a result message is transmitted, no U-ACK message is transmitted. Therefore, in the present embodiment, since the initiator device 1 has transmitted the result message, it is regarded as the reception of the U-ACK message and the result message.

The retransmission of the result message is performed according to the same procedure as the retransmission of the start message in initiator apparatus 1. That is, when the timer 209 times out,
The result retransmission processing unit 211 retransmits the result message to the initiator device 1 and restarts the timer 209 (see step B7). Here, the saving of the result message is included in step B7, but the saving of the result message may not be performed in the time-up process.

If the detected event is the reception of the result ACK message from the initiator apparatus 1, the result confirmation processing unit 205 stops the timer 209 (step B8).
reference). Then, the responder apparatus 3 ends the data transfer process.

In the second embodiment described above, when the responder returns a result message to the initiator, the U-
Do not send ACK message. Instead, the transmission of the result message assumes that both the result message and the U-ACK message have been transmitted. Therefore, according to the present embodiment, the number of transmitted messages is reduced, and transmission efficiency can be improved.

(Third Embodiment) Next, a communication system according to a third embodiment of the present invention will be described. In the communication system according to the present embodiment, the initiator device is the same as that according to the above-described first embodiment. On the other hand, as shown in FIG. 8, the responder apparatus 4 according to the present embodiment has the configuration of the responder apparatus 2 shown in FIG.
Further, a timer 214, a timer 215, and a transmission determination processing unit 216 are provided.

That is, in the present embodiment, the start instruction processing unit 202, the start response processing unit 203, the result request processing unit 204, the result confirmation processing unit 205, the S-AC
K transmission processing section 206 and U-ACK transmission processing section 207
, A result transmission processing unit 208, a timer 209, a storage unit 210, a result retransmission processing unit 211, a timer 214,
The timer 214 and the transmission determination processing unit 216 constitute a communication processing layer device on the responder side. Note that the upper layer and the communication processing layer are, for example, WS
It corresponds to a P layer and a WTP layer. Examples of the message transmitting / receiving device 212 include a TCP layer device or a UDP layer device.

In the present embodiment, the timer 214
It is started by the start instruction processing unit 202 and notifies the transmission determination processing unit 216 of time-up when a preset time has elapsed. The timer 215 is activated by the transmission determination processing unit 216, and notifies the transmission determination processing unit 216 of time-up when a preset time has elapsed. In the present embodiment, the time set in timer 215 is
The time is longer than the time set in the timer 214.

The transmission determination processing section 216 receives a time-up notification from the timers 214 and 215. Also,
The transmission determination processing unit 216 determines that the start instruction processing unit 202
Receiving a transmission request for an ACK message, receiving a transmission request for a U-ACK message from the start response processing unit 203, and further receiving a transmission request for a result message from the result request processing unit 204; Then, the transmission determination processing unit 204 determines the S-ACK message,
Coordinate the transmission request of the U-ACK message and the result message. Specifically, the transmission determination processing unit 204, upon receiving those requests, transmits the S-ACK transmission processing unit 206,
U-ACK transmission processing unit 207 or result transmission processing unit 20
8 is selected as an appropriate output destination, and a transmission request is supplied to the selected output destination. In particular, when receiving the U-ACK message transmission request from the start response processing unit 203, the transmission determination processing unit 204
In some cases, the timer 215 is started according to the result of the determination.

Here, the operation of the communication system according to the third embodiment will be described in detail with reference to FIGS. FIG. 9 shows a protocol exchange according to the present embodiment. FIG. 10 is a flowchart showing the operation of the responder apparatus 4. Since the operation of the initiator apparatus 1 is the same as that of the first embodiment, the description thereof is omitted.

When the responder apparatus 4 receives the start message (see step C1), the timer 214 is started (see step C2). That is, in the present embodiment, S-ACK is immediately received upon reception of the start message.
No message is returned. Upon receiving the start message, the start instruction processing unit 202 interprets the start message and determines whether or not the initiator apparatus 1 expects the transmission of the result message. Thereafter, the start instruction processing unit 202 sends the determination result to the transmission determination processing unit 2
16 is notified.

As a result, the responder apparatus 4 enters an event waiting state (see step C3), and thereafter, the responder apparatus 4 operates according to the detected event (see step C4). However, when the responder apparatus 4 is in the first event waiting state, the events that may occur at this time are a time-up of the timer 214, a start response from the upper layer device 201, and a result request from the upper layer device 201. .

If the detected event indicates that the timer 214 has expired, it is determined whether the timer 215 is operating (step C5). This event detection
If it is immediately after the first event, the timer 21
Since No. 5 is not operating, an S-ACK message is transmitted (see step C6). Thereafter, the responder apparatus 4 enters the event waiting state again.

If the detected event is the supply of a start response, the transmission determination processing unit 216
According to the notification from, the presence / absence of the possibility of transmitting the result message is determined (see step C7). If there is no possibility of transmission of the result message, the transmission determination processing unit 216
The CK transmission processing unit 207 transmits a U-ACK message (see step C8), and the responder apparatus 4 ends the data transfer processing. When there is a possibility that the result message can be transmitted, the transmission determination processing unit 216 activates the timer 215 (see step C9). Thereby, the responder device 4
Enters a new event waiting state.

The event that can occur at this point is timer 2
14; the timer 215; and the upper layer device 201 provides a result request. In particular, the time up of timer 214 can only occur if a start response occurs before timer 214 times out and timer 215 is started.

If the detected event is the time-up of the timer 214, it is determined whether or not the timer 215 is operating as described above (see step C5). At this point, since the timer 215 has been activated, the transmission of the U-ACK message is performed (see step C10). Thereafter, the responder apparatus 4 enters the event waiting state again.

If the detected event is the expiration of the timer 215, it is determined whether or not the U-ACK message has already been transmitted (see step C11). As described above, in the present embodiment, the set time of the timer 215 is set longer than the set time of the timer 214. Therefore, the transmission of the U-ACK message may have already been performed in step C10. Therefore, the judgment in step C11 is required. If the transmission of the U-ACK message has not been performed yet (see step C11), at this point, the U-ACK message is transmitted.
An ACK message is transmitted (see step C12).

When the detected event is the supply of the result request, the responder apparatus 4 operates in substantially the same manner as the responder apparatus 2 according to the above-described first embodiment. However, in the present embodiment, when the timer 214 and / or the timer 215 are running, the timer 214 and / or the timer 215 are stopped. Specifically, when the result request processing unit 204 is supplied with a start request from the upper layer device 201, the transmission determination processing unit 216 determines whether or not the timer 214 is operating (see step C13). If is operating, the timer 214 is stopped (see step C14). Next, the transmission determination processing unit 216
It is determined whether the timer 215 is operating (see step C15). If the timer 215 is operating, the timer 215 is stopped (see step C16). Thereafter, the transmission determination processing unit 216 issues a result message transmission request to the result transmission processing unit 208. The result transmission processing unit 208, via the message transmitting / receiving device 212,
At the same time as transmitting the result message, the timer 209 is started. Further, the result transmission processing unit 208 stores the transmitted result message in the storage unit 210 (see step C17). Thereafter, the responder apparatus 4 enters an event waiting state.

If the detected event is the expiration of the timer 209, the result retransmission processing unit 211 retrieves the result message from the storage unit 210 and transmits the result message via the message transmitting / receiving device 212 (step C18). reference). Then, the responder device 4
Enters the event waiting state.

If the detected event is the reception of the result ACK message, the result confirmation processing unit 205 stops the timer 209 (see step C19). And
Responder apparatus 4 ends the data transfer process.

In the third embodiment described above, if a start response or a result request is supplied from the upper layer device of the responder during the waiting time for returning the ACK message of the responder, the S-ACK message or the S-ACK message is returned. -ACK and UA
Do not send CK. Thereby, the number of messages to be transmitted is reduced, and transmission efficiency is improved.

The initiator device and the responder device described in the first to third embodiments can be constituted by a processor, a memory, and a program. Here, when the program is executed by the processor, it causes the processor to operate as an initiator device or a responder device,
It includes software instructions for performing the above-described processes.

Such a program may be recorded on a recording medium readable by a processor. The recording medium is, for example, a magnetic disk, an optical disk, a semiconductor memory, or the like.

In the first to third embodiments described above, the start confirmation is always made by the upper layer device 201 of the responder.
Is notified to the upper layer device 11 of the initiator. Accordingly, by supplying the start confirmation, the upper layer device 11 of the initiator can know that the upper layer device 201 of the responder has responded.

When the upper layer device 11 of the initiator intends to obtain other things from the start confirmation, the notification timing of the start confirmation may be changed. In this case, there are three types of possible start confirmation timings, for example, as shown in FIG.

In the first case, the upper layer device 11 of the initiator sets the communication processing layer device of the initiator (specifically,
When a start request is supplied to the start request processing unit 12),
The start confirmation result instruction processing unit 17 immediately notifies the start upper layer device 11 of the start confirmation. This first
In the case, the upper layer device 11 of the initiator can know that the lower layer has received the start request by receiving the start confirmation.

In the second case, upon confirming the reception of the S-ACK message, the start confirmation result instruction processing unit 17 notifies the upper layer device 11 of the start confirmation.
Here, the S-ACK message indicates that the responder apparatus has received the start message. Therefore, in the second case, the upper layer device 11 can know that the responder apparatus has received the start message by receiving the start confirmation.

In the third case, upon confirming the reception of the U-ACK message, the start confirmation result instruction processing unit 17 notifies the upper layer device 11 of the start confirmation.
Here, the U-ACK message indicates that the upper layer device 201 in the responder apparatus has responded to the start message. Therefore, in the third case, the upper layer device 11 can know that the upper layer device 201 of the responder apparatus has returned a response to the start message by receiving the start confirmation.

As described above, the start confirmation result instruction processing unit 17
By changing the timing at which the upper layer device 11 notifies the upper layer device 11 of the start confirmation, the information obtained by the upper layer device 11 from the start confirmation can be changed. This allows
Depending on the type of the upper layer device 11, the notification timing of the start confirmation can be selected. As described above, the WTP has a function called User Acknowledgement as an option. For example, in the case of using this User Acknowledgement function in the WAP network, the timing of the third case may be adopted, and when not using the function, the timing of the first case or the second case may be adopted.

[0097]

As described above, according to the present invention,
The variation of the round trip time with respect to the start message observed by the initiator is reduced, and the retransmission of the start message is reduced.

Further, according to the present invention, it is possible to reduce the number of messages circulating on the transmission path.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a configuration of a communication system according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a protocol exchange in the communication system according to the first embodiment of the present invention.

FIG. 3 is a flowchart illustrating an operation of an initiator device in the communication system according to the first embodiment of the present invention.

FIG. 4 is a flowchart illustrating an operation of a responder apparatus in the communication system according to the first embodiment of the present invention.

FIG. 5 is a block diagram schematically illustrating a configuration of a responder apparatus in a communication system according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating an example of a protocol exchange in a communication system according to a second embodiment of the present invention.

FIG. 7 is a flowchart for explaining an operation of a responder apparatus in the communication system according to the second embodiment of the present invention.

FIG. 8 is a block diagram schematically showing a configuration of a responder apparatus in a communication system according to a third embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of a protocol exchange in a communication system according to a third embodiment of the present invention.

FIG. 10 is a flowchart illustrating an operation of a responder apparatus in a communication system according to a third embodiment of the present invention.

FIG. 11 is a diagram for explaining output timing of start confirmation.

FIG. 12 is a diagram schematically showing a network configuration related to WAP.

FIG. 13 is a diagram illustrating an example of a WTP protocol exchange based on a class 2 transaction when User Acknowledgement is not used.

FIG. 14 is a diagram illustrating another example of a WTP protocol exchange based on a class 2 transaction when User Acknowledgement is not used.

FIG. 15 is a diagram showing an example of a WTP protocol exchange based on a class 1 transaction when User Acknowledgement is not used.

FIG. 16 is a diagram showing another example of a WTP protocol exchange based on a class 1 transaction when User Acknowledgement is not used.

FIG. 17 is a diagram for explaining a case where a synchronization shift occurs between two upper-layer devices.

FIG. 18 is a diagram illustrating an example of a WTP protocol exchange based on a class 1 transaction when User Acknowledgement is used.

FIG. 19 is a diagram illustrating an example of a WTP protocol exchange based on a class 2 transaction when User Acknowledgement is used.

FIG. 20 is a diagram illustrating another example of the WTP protocol exchange based on a class 2 transaction when User Acknowledgement is used.

FIG. 21 is a diagram illustrating an example of a WTP protocol exchange (class 1) for describing retransmission.

FIG. 22 is a diagram illustrating an example of a WTP protocol exchange (class 2) for describing retransmission.

FIG. 23 is a diagram illustrating another example of the WTP protocol exchange (class 2) for describing retransmission.

[Explanation of symbols]

 Reference Signs List 1 initiator apparatus 11 upper layer device 12 start request processing unit 13 timer 14 storage unit 15 retransmission processing unit 16 message transmission / reception device 17 start confirmation / result instruction processing unit 18 result response processing unit 2 responder apparatus 201 upper layer device 202 start instruction Processing unit 203 Start response processing unit 204 Result request processing unit 205 Result confirmation processing unit 206 S-ACK transmission processing unit 207 U-ACK transmission processing unit 208 Result transmission processing unit 209 Timer 210 Storage unit 211 Result retransmission processing unit 212 Message transmission / reception device 213 Message holding unit 214 Timer 215 Timer 216 Transmission determination processing unit 3 Responder device 4 Responder device

Claims (52)

[Claims] 1. A communication system in which an initiator device has a first communication processing layer device and a first upper layer device, and a responder device has a second communication processing layer device and a second upper layer device, A reliable data transfer method performed between an initiator device and the responder device, comprising: supplying a start request from the first upper layer device to the first communication processing layer device; Transmitting a start message from the first communication processing layer device to which the start request has been supplied to the second communication processing layer device; and transmitting the start message from the second communication processing layer device receiving the start message to the second upper layer. Notifying a start instruction corresponding to the start message to the layer device; and receiving the start message by the second communication processing layer device itself. Transmitting a first acknowledgment message from the second communication processing layer device to the first communication processing layer device, wherein the second upper layer device sends a start response corresponding to the start message to the first communication processing layer device. A second acknowledgment message indicating that the second communication processing layer device has been supplied to the second communication processing layer device.
Transmitting from the communication processing layer device to the first communication processing layer device; and a result message indicating that the second upper layer device has supplied a result request corresponding to the start instruction to the second communication processing layer device. From the second communication processing layer device to the first communication processing layer device. 2. A data processing method executed by the first communication processing layer device in the initiator apparatus to realize the data transfer method according to claim 1, wherein the first communication processing layer device is In a data processing method including a retransmission timer, when the start instruction is supplied from the first upper layer device, a first step of generating the start message; and activating the retransmission timer and generating the start message. A second step of holding a start message; a third step of transmitting the generated start message to the second communication processing layer device; a fourth step of entering an event waiting state; A fifth step of detecting an event that has occurred, and a case where the detected event is a time-up of the retransmission timer. A sixth step of retransmitting the held start message and restarting the retransmission timer and returning to the fourth step; and when the detected event is the reception of an acknowledgment message, the retransmission timer A step of stopping the acknowledgment message received and determining whether or not the received acknowledgment message is the second acknowledgment message, and returning to the fourth step if the determination result is no And a ninth step of notifying the first upper layer device of a start confirmation indicating that the second acknowledgment message has been received, if the result of the determination in the eighth step is positive. A data processing method comprising: 3. The method according to claim 9, wherein the start message is either a first start message requesting only the acknowledgment message or a second start message requesting both the acknowledgment message and the result message. Immediately after the step of determining whether the transmitted start message is the first start message or the second start message, and if the transmitted start message is the second start message, ,
3. The data processing method according to claim 2, further comprising a tenth step returning to said fourth step. 4. An eleventh step of stopping the retransmission timer when the detected event is the reception of a result message, and transmitting a result indication indicating that the result message has been received to the first upper layer device. The data processing method according to claim 3, further comprising a twelfth step of performing notification. 5. A data processing method executed by the second communication processing layer device in the responder apparatus to realize the data transfer method according to claim 1, wherein the first step of receiving the start message is performed. A second step of transmitting the first acknowledgment message indicating the reception of the start message to the first communication processing layer device; a third step of entering an event waiting state; A fourth step of detecting an event that has occurred; and a fifth step of transmitting the second acknowledgment message to the first communication processing layer device when the detected event is the supply of the start response. A data processing method comprising the steps of: 6. The method according to claim 5, wherein the start message is either a first start message requesting only the acknowledgment message or a second start message requesting both the acknowledgment message and the result message. Immediately after the step of determining whether the received start message is the first start message or the second start message, if the received start message is the second start message, The data processing method according to claim 5, further comprising a sixth step of returning to the third step. 7. When the detected event is the supply of the result request, a seventh step of transmitting the result message when the second communication processing layer device includes a retransmission timer; 8. The data processing method according to claim 6, further comprising: activating the program, holding the transmitted result message, and returning to the third step. 8. A ninth method for retransmitting the held result message and restarting the retransmission timer when the detected event is the expiration of the retransmission timer.
8. The data processing method according to claim 7, further comprising the step of: 9. A data processing method executed by the second communication processing layer device in the responder apparatus to realize the data transfer method according to claim 1, wherein the start message is the acknowledgment message. A first start message requesting only the first message, or a second start message requesting both the acknowledgment message and the result message; a first step of receiving the start message; A second step of transmitting the first acknowledgment message indicating reception to the first communication processing layer device; a third step of entering an event waiting state; A fourth step of detecting, and if the detected event is the supply of the start response, the receiving Start message determines which of the first start message and the second start message, if the received start message is the second start message, the flow returns to the third step 5
And in the fifth step, when the received start message is the first start message, transmitting a second acknowledgment message to the first communication processing layer device. A data processing method comprising: 10. A seventh step of transmitting the result message when the detected event is the supply of the result request, wherein the second communication processing layer device includes a retransmission timer; And holding the transmitted result message, and returning to the third step. 8. The data processing method according to claim 9, further comprising: 11. The method according to claim 10, further comprising a ninth step of retransmitting the held result message and restarting the retransmission timer when the detected event is that the retransmission timer has expired. Data processing method. 12. A data processing method executed by the second communication processing layer device in the responder apparatus to realize the data transfer method according to claim 1, wherein the start message is the acknowledgment message. A first start message requesting only the first message, or a second start message requesting both the acknowledgment message and the result message, wherein the second communication processing layer device has a first timer, a second timer, and a retransmission timer. A first step of receiving the start message; a second step of activating the first timer; a third step of entering an event wait state; and an event that occurs when an event occurs. A fourth step of detecting an event, and if the detected event is the time-up of the first timer, If the second timer is running, the second acknowledgment message is sent to the first communication processing layer device, while if the second timer is not running, the second acknowledgment message is sent to the first communication processing layer device. A fifth step of transmitting to the first communication processing layer device and returning to the third step; and when the detected event is the supply of the start response, the received start message is transmitted to the first communication processing layer device. Determining whether the received start message is the start message or the second start message, and if the received start message is the second start message, activating the second timer and returning to the third step; Step 6; and in the sixth step, when the received start message is the first start message, the second acknowledgment message is A seventh step of transmitting to the first communication processing layer device, and, if the detected event is the expiration of the second timer, determining whether the second acknowledgment message has already been transmitted. Judge, return to the third step if it has been transmitted, and return to the second step if it has not been transmitted.
An eighth step of transmitting an acknowledgment message and then returning to the third step, a ninth step of transmitting the result message when the detected event is the supply of the result request, A tenth step of activating a retransmission timer and holding the transmitted result message and returning to the third step; and when the detected event is the retransmission timer time-up, the held result is stored. An eleventh step of retransmitting the message and restarting the retransmission timer. 13. When the ninth step is performed,
Before transmitting the result message, if the first timer and / or the second timer is running, the active first
The data processing method according to claim 12, wherein the timer and / or the second timer are stopped. 14. A communication processing layer device that can be used as a first communication processing layer device of the initiator apparatus in a communication system according to the data transfer method according to claim 1, wherein: a retransmission timer; Generating the start message when the start instruction is supplied from the first upper layer device, transmitting the generated start message to the second communication processing layer device, and activating the retransmission timer. A start request processing unit that stores the generated start message in the storage unit; and when the retransmission timer times out, retransmits the start message stored in the storage unit and the retransmission timer. And a retransmission processing unit that restarts the retransmission timer when the first and / or second acknowledgment message is received. Communication processing layer device and a start confirmation result indicating processing unit for stopping. 15. The start request processing unit determines whether or not the received acknowledgment message is the second acknowledgment message. If the result of the determination is positive, the second acknowledgment message is returned. The first upper layer device is notified of a start confirmation indicating that a message has been received.
5. The communication processing layer device according to 4. 16. In the case where the start message is either a first start message requesting only the acknowledgment message or a second start message requesting both the acknowledgment message and the result message,
The start request processing unit may determine that the start message is the first message.
The start confirmation result instruction processing unit notifies the start confirmation result instruction processing unit which of the start message and the second start message is. If the transmitted start message is the second start message, The communication processing layer device according to claim 15, wherein the communication processing layer device waits until receiving the result message. 17. The start confirmation result instruction processing unit, upon receiving the result message, stops the retransmission timer and sends a result instruction indicating that the result message has been received to the first upper layer device. 17. The communication processing layer device according to claim 16, which notifies. 18. A communication processing layer device that can be used as a second communication processing layer device of the responder apparatus in a communication system according to the data transfer method according to claim 1, wherein upon receiving the start message, A start instruction processing unit that notifies the second upper layer device of the start instruction and generates a transmission request of a first acknowledgment message; and the first acknowledgment according to the transmission request of the first acknowledgment message. A first acknowledgment message transmission processing unit that transmits a message to the first communication processing layer device; a start response processing unit that is supplied with the start response and generates a transmission request of the second acknowledgment message; According to the transmission request for the second acknowledgment message, the second acknowledgment message is sent to the first communication processing layer device. Communication processing layer device and a second acknowledgment processing unit that transmits Te. 19. A result request processing unit that receives the result request and generates a result message transmission request, a retransmission timer and a storage unit, generates the result message according to the result message transmission request, A result transmission processing unit that transmits the generated result message to the first communication processing layer device, activates the retransmission timer, and stores the generated result message in the storage unit. 19. The communication processing layer device of claim 18, further comprising: 20. The communication processing layer device according to claim 19, further comprising a result retransmission processing unit that retransmits the result message stored in the storage unit and restarts the retransmission timer when the retransmission timer times out. 21. The data transfer method according to claim 1, wherein the start message requests only the acknowledgment message or a second start message requests both the acknowledgment message and the result message. A communication processing layer device that can be used as the second communication processing layer device of the responder apparatus in a communication system according to two types of data transfer methods of a start message, wherein when the start message is received, the second upper layer A start instruction process for notifying the device of the start instruction, generating a transmission request for a first acknowledgment message, and determining whether the start message is the first start message or the second start message. And a transmission request for the second acknowledgment message, supplied with the start response. A start response processing unit that generates the result request; a result request processing unit that is supplied with the result request and generates a transmission request for the result message; A first acknowledgment message transmission processing unit for transmitting to the first communication processing layer device; and if the received start message is the first start message, according to the determination of the start instruction processing unit,
While passing through the transmission request for the second acknowledgment message received from the start response processing unit, if the received start message is the second start message, the transmission request for the second acknowledgment message is discarded. And a message holding unit for passing a transmission request for the result message received thereafter, and the second acknowledgment message is sent to the first communication processing layer according to a transmission request for the second acknowledgment message passed through the message holding unit. A second acknowledgment message transmission processing unit for transmitting to the device, and a result transmission process for transmitting the result message to the first communication processing layer device in accordance with a transmission request for the result message passed through the message holding unit And a communication processing layer device. 22. The apparatus further comprising a retransmission timer and a storage unit,
The result transmission processing unit transmits the result message to the first
22. The communication processing layer device according to claim 21, wherein, when transmitting to the communication processing layer device, the retransmission timer is started and the generated result message is stored in the storage unit. 23. The communication processing layer device according to claim 22, further comprising a result retransmission processing unit that retransmits the result message stored in the storage unit and restarts the retransmission timer when the retransmission timer times out. 24. The data transfer method according to claim 1, wherein the start message requests only the acknowledgment message or a second start message requests both the acknowledgment message and the result message. A communication processing layer device that can be used as the second communication processing layer device of the responder apparatus in a communication system according to two types of data transfer methods of a start message, wherein a first timer and a start message are received. Notifying the second upper layer device of the start instruction, generating a transmission request for a first acknowledgment message, and activating the first timer, wherein the start message includes the first start message and the first (2) a start instruction processing unit that determines which of the start messages is received; A start response processing unit that generates a transmission request for the second acknowledgment message; a result request processing unit that receives the result request and generates a transmission request for the result message; A transmission request for the first acknowledgment message and a transmission request for the second acknowledgment message connected to a start response processing unit, the first timer, the second timer, and the result request processing unit, in response to an event that has occurred A transmission determination processing unit that passes through any of the transmission requests for the result message; and a first communication processing unit that processes the first acknowledgment message according to the transmission request for the first acknowledgment message that has passed through the transmission determination processing unit. A first acknowledgment message transmission processing unit for transmitting to the layer device, and transmission of the second acknowledgment message passing through the transmission determination processing unit A second acknowledgment message transmission processing unit for transmitting the second acknowledgment message to the first communication processing layer device in accordance with the request; and a transmission result of the result message passed through the transmission determination processing unit. A communication processing layer device comprising: a result transmission processing unit that transmits a message to the first communication processing layer device. 25. The transmission determination processing unit, according to a determination of the start instruction processing unit, when the received start message is the first start message, the second confirmation received from the start response processing unit. The transmission request of the response message is passed through, and when the received start message is the second start message, the transmission request of the second acknowledgment message is discarded, and the second timer is started. 25. The communication processing layer device according to 24. 26. The transmission determining means, when the first timer times out, if the second timer is not in operation, passes the transmission request of the first acknowledgment message, and the second timer determines 26. The communication processing layer device according to claim 25, wherein the transmission request of the second acknowledgment message is passed through when the device is in operation. 27. The transmission acknowledgment message, wherein when the second timer times out, if the transmission request for the second acknowledgment message has not yet passed through the transmission judgment means, the second acknowledgment message 27. The communication processing layer device according to claim 26, wherein the transmission request of the communication processing layer is passed. 28. The transmission determining means, when receiving the transmission request for the result message, if the first timer and / or the second timer is operating, the first timer and / or the second timer being operated. 28. The communication processing layer device of claim 27, wherein two timers stop. 29. The apparatus further comprising a retransmission timer and a storage unit,
The result transmission processing unit transmits the result message to the first
29. The communication processing layer device according to claim 28, wherein, when transmitting to the communication processing layer device, the retransmission timer is started and the generated result message is stored in the storage unit. 30. The communication processing layer device according to claim 29, further comprising: a result retransmission processing unit that retransmits the result message stored in the storage unit and restarts the retransmission timer when the retransmission timer times out. 31. A recording medium readable by a processor, the recording medium recording a program which, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 14. 32. A recording medium readable by a processor, wherein the recording medium records a program that, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 15. 33. A recording medium readable by a processor, the recording medium recording a program which, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 16. 34. A storage medium readable by a processor, wherein the storage medium stores a program that, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 17. 35. A recording medium readable by a processor, the recording medium recording a program which, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 18. 36. A storage medium readable by a processor, wherein the storage medium stores a program that, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 19. 37. A storage medium readable by a processor, wherein the storage medium stores a program that, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 20. 38. A recording medium readable by a processor, the recording medium recording a program which, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 21. 39. A recording medium readable by a processor, wherein the recording medium records a program which, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 22. 40. A recording medium readable by a processor, wherein the recording medium records a program which, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 23. 41. A recording medium readable by a processor, wherein the recording medium records a program which, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 24. 42. A storage medium readable by a processor, wherein the storage medium stores a program that, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 25. 43. A storage medium readable by a processor, wherein the storage medium stores a program that, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 26. 44. A storage medium readable by a processor, wherein the storage medium stores a program which, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 27. 45. A recording medium readable by a processor, wherein the recording medium stores a program which, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 28. 46. A storage medium readable by a processor, wherein the storage medium stores a program that, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 29. 47. A storage medium readable by a processor, wherein the storage medium stores a program which, when executed by the processor, causes the processor to operate as the communication processing layer device according to claim 30. 48. A data communication method performed between an initiator communication device and a responder communication device, each having an upper layer of a communication protocol, wherein the responder communication device transmits data from the initiator communication device. When returning an acknowledgment message in response to a communication start message, a first acknowledgment message simply indicating that the start message has been received on the responder communication device side, and an upper layer of the communication protocol for the start message. And a second acknowledgment message indicating that a response has been received from the data communication method. 49. A responder communication device having an upper layer of a communication protocol for performing data communication with an initiator communication device, wherein the responder communication device receives a start message sent from the initiator communication device. Means for transmitting a first acknowledgment message indicating that there is a response from the upper layer of the communication protocol to the start message, and means for transmitting a second acknowledgment message indicating that there is a response from the upper layer of the communication protocol. Responder communication device. 50. A communication protocol upper layer, means for sending a first acknowledgment message indicating that a data communication start message has been received, and a response from the communication protocol upper layer to the start message. An initiator communication device for performing data communication with a responder communication device including means for sending a second acknowledgment message indicating that an upper layer of a communication protocol,
Message sending means for sending the start message in response to a data communication start request from the upper layer, and determining notification of the communication protocol to the upper layer based on the first and second acknowledgment messages An initiator communication device comprising: a notification determination unit. 51. A recording medium recording a control program for controlling an operation of a responder communication device for performing data communication with an initiator communication device having an upper layer of a communication protocol, wherein the program comprises: When the responder communication device receives a start message of data communication from the initiator communication device and returns an acknowledgment message, a first confirmation indicating that the start message is simply received on the responder communication device side A recording medium for controlling to use a response message and a second acknowledgment message indicating that a response from the upper layer of the communication protocol to the start message has been received. 52. A means for transmitting a first acknowledgment message indicating that a data communication start message has been received, and a second acknowledgment indicating that a response to the start message has been received from an upper layer of a communication protocol. And a control program for controlling the operation of the initiator communication device for performing data communication with a responder communication device including a means for sending a response message. Sending the start message in response to a data communication start request, and determining a notification to an upper layer of the communication protocol by judging from the first and second acknowledgment messages. Characteristic recording medium.