JP2013232710A - Access point capable of efficient data transfer and radio slave unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an access point that can efficiently perform end-to-end communication even if the communication state of a radio network is bad.SOLUTION: If the communication state of a radio network is bad and even link is disconnected, an access point as a proxy of a radio slave unit transmits an instruction to keep the communication to a network terminal which is a communication destination terminal. This allows the communication to be kept without disconnecting the communication between both, and when the link is restored, the communication between both is quickly resumed by stopping transmission of the instruction. Of course, in order to do this operation, there is no need for additional hardware to the access point, and therefore an effect not to lead to cost rise of a machine is also obtained at the same time.

Description

  The present invention relates to a wireless network, and relates to an access point and a wireless network system capable of performing stable communication regardless of the quality of radio waves.

  A general connection form of a wireless LAN network is generally called an infrastructure mode in which a wireless slave device that is a wireless client connects to an access point that is a parent device. FIG. 1 shows a general configuration of an infrastructure mode. A wireless slave device 101 can communicate with a network terminal 103 and a network terminal 104 via an access point 102.

  A wireless network is unstable compared to a wired network due to the influence of radio wave interference and the like. For example, when the wireless client 101 is communicating with the network terminal 103 in FIG. 1, communication between the access point 102 and the network terminal 103 is smooth, but communication between the wireless client 101 and the access point 102 is successful. When communication is not successful, the overall performance of communication between the wireless client 101 and the network terminal 103 decreases. If the wireless communication link is disconnected, the TCP session between both terminals may be lost. In this case, if a large amount of data has been transmitted / received in the TCP session, the transmission / reception of data must be started again from the beginning by resetting the TCP session.

  As described above, in wireless communication, there is always a risk of link disconnection, and the inefficiency of data transfer caused by this has been a problem. Patent Document 1 discloses an invention for improving such a problem.

  In the invention disclosed in Patent Document 1, an access point that operates as a bridge between a wired network and a wireless network has a data storage area. When communication of the wireless network is disconnected, the access point is wired in the storage area. The network data is received by proxy, and when the wireless network is resumed, the received data is transmitted to the wireless device.

JP 2008-67192 A

  According to the invention disclosed in Patent Document 1, it is possible to resume without any problem even if the wireless network communication is interrupted. However, it is necessary to provide a temporary data storage area in the access point itself, which increases the cost of the device. Furthermore, it is not easy to estimate in advance how much capacity of this storage area is required, and there is a problem that the cost of the equipment will naturally increase if it is provided more than necessary for safety reasons.

  The present invention is to solve such a problem. That is, an object of the present invention is to provide an access point that can efficiently perform end-to-end communication even when the wireless network communication status is poor.

  A first form according to the present invention is a repeater that relays data link communication between a first network device and a second network device, and is between the first network device and the second network device. Communication management means for managing higher-order communication (higher-order communication) than data-link communication, and data for detecting that data-link communication between itself and the first network device or between itself and the second network device is disconnected When the link communication disconnection detecting means and the data link communication disconnection detecting means detect disconnection of the data link communication, the network device corresponding to the data link communication that is not disconnected is addressed and the disconnected data link communication is supported. A higher level communication that uses the address of the network device as the source address, and is compatible with disconnected data link communication. A proxy response means for transmitting an instruction to maintain higher-level communication with the network device to perform, a data link communication return detection means for detecting that the data link communication disconnection detected by the data link communication disconnection detection means has been recovered, and a data link And a proxy response stop instruction means for stopping the proxy response by the proxy response means when the communication return detection means detects the return of the data link communication.

  The second form according to the present invention is a wireless access point to which a wireless slave is connected, and the connection between the TCP session management means for managing the TCP session of the wireless slave and the wireless slave is disconnected. Disconnection detecting means for detecting this and the address of the wireless slave device in the TCP session managed by the TCP session management means as a transmission source address on the TCP session toward the destination terminal of the wireless slave device TCP session maintenance proxy response means for transmitting contents for maintaining a session, proxy response start instruction means for instructing a proxy response by the TCP session maintenance proxy response means when the disconnection detection means detects disconnection, and a disconnected wireless device The connection return detection means for detecting that the connection with the machine has returned, and the connection return detection means If issued, and a proxy response stop instruction means for instructing a stop of the initiated proxy response by the proxy response start instruction means.

  Preferably, the connection to be disconnected and restored detected by the disconnect detection means and the connection return detection means includes at least a connection by the data link layer.

  Preferably, the content for maintaining the TCP session includes any one of keep alive and window size 0 (zero) in TCP communication.

  According to a third aspect of the present invention, there is provided a repeater that relays data link communication between a first network device and a second network device, and a data link between the first network device and the second network device. Communication management means for managing higher-level communication (higher-level communication) than communication, and data-link communication for detecting that data-link communication between itself and the first network device or between itself and the second network device is disconnected When the disconnection detecting means and the datalink communication disconnection detecting means detect disconnection of the datalink communication, the network equipment corresponding to the disconnected datalink communication is destined to the network equipment corresponding to the datalink communication that is not disconnected. Corresponding to disconnected data link communication that is a higher level communication with the source address as the source address Proxy response means for transmitting an instruction to maintain higher-level communication with the network device, data link communication return detection means for detecting that the disconnection of the data link communication detected by the data link communication disconnection detection means has been recovered, and data link communication When the return detection means detects the return of data link communication, it is a program that functions as a proxy response stop instruction means for stopping the proxy response by the proxy response means.

  According to a fourth aspect of the present invention, the connection between the wireless slave unit and the TCP session management means for managing the TCP session of the wireless slave unit is disconnected from the wireless access point to which the wireless slave unit is connected. The disconnection detection means to be detected and the address of the wireless slave device in the TCP session managed by the TCP session management means as the transmission source address, the TCP session is directed to the destination terminal of the wireless slave device on the TCP session. A TCP session maintenance proxy response means for transmitting contents to be maintained; a proxy response start instruction means for instructing a proxy response by the TCP session maintenance proxy response means when the disconnection detection means detects disconnection; and a disconnected wireless slave unit The connection return detection means for detecting that the connection has been restored and the connection return detection means detect the return of the connection. If the proxy response stop instruction means for instructing to stop has been proxy response initiated by the proxy response start instructing means, a program to function with.

  Preferably, the connection to be disconnected and restored detected by the disconnect detection means and the connection return detection means includes at least a connection by the data link layer.

  Preferably, the content for maintaining the TCP session includes any one of keep alive and window size 0 (zero) in TCP communication.

  According to a fifth aspect of the present invention, there is provided a wireless network system in which a wireless slave device and a wired network device communicate with each other via an access point, wherein the access point manages a TCP session of the wireless slave device. On the TCP session, the disconnection detecting means for detecting that the connection with the wireless slave is disconnected, and the address of the wireless slave in the TCP session managed by the TCP session management means as the source address, A TCP session maintenance proxy response means for transmitting the contents for maintaining the TCP session toward the destination terminal of the wireless slave unit, and a proxy response by the TCP session maintenance proxy response means when the disconnection detection means detects disconnection The connection between the proxy response start instruction means and the disconnected wireless slave unit is restored. A connection return detecting means for detecting this, and a proxy response stop instructing means for instructing to stop the proxy response started by the proxy response start instructing means when the connection return detecting means detects the return of the connection. A slave unit is a wireless network system comprising disconnection avoiding means that does not disconnect a TCP session when the connection with the access point is disconnected.

  The access point disclosed in the present invention maintains the communication with the network terminal, which is the communication partner terminal, as a proxy for the wireless slave unit even if the communication status of the wireless network is poor and the link is disconnected. Send instructions to do. As a result, the communication between the two can be maintained without being disconnected, and when the link is restored, the communication between the two can be quickly resumed by stopping the transmission of the instruction. Of course, when such an operation is performed, no additional hardware is required at the access point, so that the effect of not increasing the cost of the device can be obtained.

Embodiments according to the present invention will be described below with reference to the drawings.
[Example 1]
[System overview]

FIG. 1 is an overall view of a system according to the present invention. Since the individual elements have already been described, details are omitted. In the following description, a case where the wireless slave device 101 communicates with the network terminal 103 via the access point 102 will be described as an example.
[System overview]

  FIG. 2 is a functional block diagram of the access point 102 according to the present invention. The access point 102 is a device that bridges the wireless interface 211 and the wired interface 212.

  The TCP session management unit 201 is a unit that manages a TCP session established through both the above-described interfaces. Specifically, the addresses and port numbers of the terminals on both sides are managed. Since there are many TCP sessions in a general wireless network, it is possible to manage a plurality of sessions. Note that the managed session information is stored in the storage unit 213 and is updated whenever necessary.

  The link disconnection detection unit 202 is a unit that monitors the wireless interface 211 and detects link disconnection. Of course, it is known which TCP session the link to be monitored belongs to. When link disconnection is detected, the proxy response means 203 described later is instructed to start a proxy response.

  Based on the instruction from the link disconnection detection unit 202, the proxy response unit 203 sends a response indicating that the TCP session is maintained to the network terminal 103 on the wired interface 212 side of the TCP session in which the link disconnection has occurred. 101 as a proxy.

  Since this response is performed on behalf of the wireless slave device 101, the transmission source address and port number of the wireless slave device 101 are naturally used.

  As a specific example of the response for maintaining the session, one is KeepAlive (keep alive) communication in TCP communication. As another example, a response indicating that the window size is full (full) is one specific example. The window size being full means that the receiving side cannot accept data, and is normally set to 0 (zero).

  Similar to the above-described link disconnection detection unit 202, the link recovery detection unit 204 is a unit that monitors the wireless interface 211 and detects that the disconnected link has recovered. When the return of the link is detected, this fact is notified to the TCP session disconnection judging means 205 described later. At the same time, the proxy response unit 203 is instructed to stop the proxy response being executed.

  The TCP session disconnection determination unit 205 is a unit that determines whether or not the TCP session with the wireless slave device 101 is disconnected. If disconnected, an instruction to notify the wireless slave device 101 of this is sent to the TCP session disconnection notification means 206 described later. Further, even when the link with the wireless slave device 101 is not restored, if the TCP session is disconnected, the TCP session management unit 201 notifies the TCP session management unit 201 of the determination. The TCP session information is deleted from the storage unit 213.

The TCP session disconnection notification means 206 notifies the wireless slave device 101 that the instructed TCP session is disconnected.
[Operation flow]

  FIG. 3 is an operation flow of the access point according to the present invention.

  In step 301, it is determined whether or not the link with the wireless slave is disconnected. If disconnected, proceed to the next step, otherwise repeat this determination.

  In step 302, a proxy response is started toward the network terminal 103. This proxy response is performed as a proxy of the wireless slave device 101 as described above.

  In step 303, it is determined whether or not the link with the wireless slave device 101 has been restored.

  In step 304, it is determined whether the TCP session of the restored link is disconnected. If disconnected, the process proceeds to step 305 to notify the wireless slave device 101 that the TCP session is disconnected. Otherwise, return to the first step.

  In step 306, the proxy response started in step 302 is stopped.

  In step 307, as in step 304, it is determined whether the TCP session is disconnected. If it is disconnected, the TCP session information is deleted from the storage means 213 in step 308 and the process returns to step 301. If not disconnected, repeat proxy response.

The operations of steps 301, 302, 303, and 305 are executed with reference to the information in the session information storage means 213.
[Example 2]

  In the first embodiment described above, the TCP session is maintained by the access point 102 functioning as a proxy for the wireless slave device 101. However, in some cases, specifically, depending on the operation of the application using the TCP session in the wireless slave device 101, when the link disconnection occurs, the TCP session itself is immediately disconnected. In this case, no matter how much the access point 102 maintains a TCP session with the network terminal 103 as a proxy, the wireless slave device 101 cannot be resumed on the TCP session after the link is restored. The TCP session disconnection determination unit 205 described in the first embodiment is for processing a session disconnection situation that occurs due to such a cause.

  The present embodiment relates to a function to be incorporated in the wireless slave device 101 in order to avoid such a problem.

  Specifically, the wireless slave device 101 may not issue a Reset for disconnecting the TCP session even when the wireless communication link is disconnected. Even if the upper application issues a disconnection instruction, the TCP session is maintained without transmitting Reset.

When the operation of the wireless slave device 101 is ignored in this way, the application may not operate normally even if the TCP session is resumed after the link is restored. In order to avoid such a situation, it is possible for the TCP layer to avoid a TCP disconnection instruction by making some proxy response to the application. However, the specific proxy response for the application differs depending on the operation specifications of the application, and is not mentioned in this application. In any case, by providing the wireless slave device 101 with a disconnection avoiding means that does not disconnect the TCP session, the object of the present invention can be achieved even when a higher-level application issues a TCP session disconnection instruction. It becomes.
[Other Examples]
In the above embodiments, the access point that relays between the wired network and the wireless network has been described as an example. However, the present invention is not limited to the combination of these interfaces. For example, the present invention can be applied to the case of wireless interfaces or wired networks.
[Summary]

  The details of the access point according to the present invention have been described above. That is, the access point disclosed in the present invention has a poor communication situation in the wireless network, and even if the link is disconnected, the communication is performed on the network terminal that is the communication partner terminal as a proxy for the wireless slave unit. Send instructions to maintain. As a result, the communication between the two can be put on hold, and when the link is restored, the communication between the two can be resumed quickly by stopping the transmission of the instruction. Of course, when such an operation is performed, no additional hardware is required at the access point, so that the effect of not increasing the cost of the device can be obtained.

Overall system diagram Functional block diagram of wireless handset Wireless slave unit operation flow

201 TCP session management means 202 Link disconnection detection means 203 Proxy response means 204 Link recovery detection means

Claims (9)

A repeater for relaying data link communication between a first network device and a second network device,
Communication management means for managing higher-order communication (higher-order communication) than data link communication between the first network device and the second network device;
Data link communication disconnection detection means for detecting that data link communication between itself and the first network device or between itself and the second network device is disconnected;
When the data link communication disconnection detecting means detects the disconnection of the data link communication, the address of the network device corresponding to the disconnected data link communication is transmitted to the network device corresponding to the data link communication not disconnected. Proxy response means for transmitting an instruction to maintain the higher-level communication with the network device corresponding to the disconnected data link communication in the higher-level communication as the original address;
Data link communication return detection means for detecting that the disconnection of the data link communication detected by the data link communication disconnection detection means is restored;
A proxy response stop instruction means for stopping a proxy response by the proxy response means when the data link communication return detection means detects a return of data link communication;
A repeater comprising: A wireless access point to which a wireless slave is connected,
TCP session management means for managing a TCP session of the wireless slave unit;
Disconnection detecting means for detecting that the connection with the wireless slave is disconnected;
Contents for maintaining the TCP session toward the destination terminal of the wireless slave unit on the TCP session, with the address of the wireless slave unit in the TCP session managed by the TCP session management means as a source address TCP session maintenance proxy response means for transmitting
A proxy response start instruction means for instructing a proxy response by the TCP session maintenance proxy response means when the disconnect detection means detects a disconnection;
A connection return detection means for detecting that the connection with the disconnected wireless slave device has been restored;
Proxy response stop instructing means for instructing to stop the proxy response started by the proxy response start instructing means when the connection recovery detecting means detects the return of the connection;
Wireless access point comprising.   The wireless access point according to claim 2, wherein the connection to be disconnected and restored detected by the disconnection detection unit and the connection return detection unit includes at least a connection by a data link layer.   4. The wireless access point according to claim 2, wherein the content for maintaining the TCP session includes any one of keep alive and window size 0 (zero) in TCP communication. 5. A repeater for relaying data link communication between the first network device and the second network device;
Communication management means for managing higher-order communication (higher-order communication) than data link communication between the first network device and the second network device;
Data link communication disconnection detection means for detecting that data link communication between itself and the first network device or between itself and the second network device is disconnected;
When the data link communication disconnection detecting means detects the disconnection of the data link communication, the address of the network device corresponding to the disconnected data link communication is transmitted to the network device corresponding to the data link communication not disconnected. Proxy response means for transmitting an instruction to maintain the higher-level communication with the network device corresponding to the disconnected data link communication in the higher-level communication as the original address;
Data link communication return detection means for detecting that the disconnection of the data link communication detected by the data link communication disconnection detection means is restored;
A proxy response stop instruction means for stopping a proxy response by the proxy response means when the data link communication return detection means detects a return of data link communication;
Program to function as. The wireless access point to which the wireless slave unit is connected
TCP session management means for managing a TCP session of the wireless slave unit;
Disconnection detecting means for detecting that the connection with the wireless slave is disconnected;
Contents for maintaining the TCP session toward the destination terminal of the wireless slave unit on the TCP session, with the address of the wireless slave unit in the TCP session managed by the TCP session management means as a source address TCP session maintenance proxy response means for transmitting
A proxy response start instruction means for instructing a proxy response by the TCP session maintenance proxy response means when the disconnect detection means detects a disconnection;
A connection return detection means for detecting that the connection with the disconnected wireless slave device has been restored;
Proxy response stop instructing means for instructing to stop the proxy response started by the proxy response start instructing means when the connection recovery detecting means detects the return of the connection;
Program to make it work.   7. The program according to claim 6, wherein the connection to be disconnected and restored detected by the disconnection detection unit and the connection return detection unit includes at least a connection by a data link layer.   7. The program according to claim 5, wherein the contents for maintaining the TCP session include any one of keep alive and window size 0 (zero) in TCP communication. A wireless network system in which a wireless slave unit and a wired network device communicate via an access point,
The access point is
TCP session management means for managing a TCP session of the wireless slave unit;
Disconnection detecting means for detecting that the connection with the wireless slave is disconnected;
Contents for maintaining the TCP session toward the destination terminal of the wireless slave unit on the TCP session, with the address of the wireless slave unit in the TCP session managed by the TCP session management means as a source address TCP session maintenance proxy response means for transmitting
A proxy response start instruction means for instructing a proxy response by the TCP session maintenance proxy response means when the disconnect detection means detects a disconnection;
A connection return detection means for detecting that the connection with the disconnected wireless slave device has been restored;
A proxy response stop instructing means for instructing a stop of the proxy response started by the proxy response start instructing means when the connection recovery detecting means detects the return of the connection,
The wireless slave is
A wireless network system comprising disconnection avoiding means that does not disconnect a TCP session when the connection with the access point is disconnected.