JP2004040671A - Data transfer method, communication system, transmission management apparatus, communication management program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress an increase in communication quantity caused by an ACK frame while securing accuracy in a data reception in a receiving station which requires accuracy in the reception of data. <P>SOLUTION: Each of receiving stations 200-203 is capable of implementing reply processing for redirecting the ACK frame. The data transfer method includes: a setting step for setting whether or not reply processing is to be performed for each of receiving stations 200-203; a transmitting step for transmitting data by a transmitting station 100; a receiving step for receiving the data by the receiving stations 200-203; and a discriminating step for discriminating whether or not reply processing is to be performed based upon setting by a setting part of the relevant receiving station by an ACK control part of any one of receiving stations 200-203 which receives the data. The receiving stations 200-203 are classified into predetermined receiving station groups 300-303 and it is set whether or not reply processing is to be performed in the receiving station of a group for each group. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a data transfer method by a communication system including a plurality of communication devices and capable of transferring data between the plurality of communication devices via a communication network, the method comprising: The data transfer method for transferring data to the communication device on the side.
[0002]
[Prior art]
In the case of one-to-one data transfer in a LAN (Local Area Network) system, in general, a transmitting station transmits a data frame to a receiving station, and the receiving station returns an ACK frame, which is returned from the receiving station. The transmitting station retransmits the data frame as needed based on the ACK frame. Further, it is defined that such a data transfer protocol is performed in a MAC (Media Access Control) layer of a data link layer.
[0003]
Conventional LAN systems of this type include those described in IEEE 802.11. This is a wireless LAN system employing CSMA / CA (Carrier Sense Multiple Access With Collision Aidance) as a data transfer control method in a MAC layer, and further performing retransmission in a MAC layer using an ACK frame. .
[0004]
As a wireless AV transmission system for handling AV data, there is a system described in IEEE 802.11eD2.0.
[0005]
Further, there are the following three methods of using an ACK frame of IP multicast, which has been devised as an extension protocol of IP (Internet Protocol).
[0006]
The first method is, as described in the LAN system, a method in which the receiving station notifies the transmitting station of an ACK frame indicating that the packet has been normally received.
[0007]
In the second method, the receiving stations are arranged in a tree structure (tree structure), a plurality of ACK frames notified from the receiving station, which is each node, are aggregated into one and notified to an upper node, and by repeating the same, In this method, an ACK frame is finally delivered to the transmitting station.
[0008]
The third method is a method in which NAK data indicating that the receiving station has failed in receiving a packet is notified to the transmitting station or a nearby node capable of retransmission.
[0009]
Although not related to an ACK frame, there is JP-A-10-173688 (publication date: June 26, 1998) which discloses a technology relating to data communication. In Japanese Patent Application Laid-Open No. Hei 10-173688, when data is communicated using a serial bus or the like compliant with IEEE 1394-1995, node IDs are set for a plurality of devices connected to the bus, and The device type information indicated by each node ID is inquired based on the information, and a table in which each node ID is associated with the device type information is created, so that it is possible to easily communicate with a specific node simply by specifying the node type. The technology aiming at this is disclosed.
[0010]
[Problems to be solved by the invention]
Multiple data transfer partners, such as broadcast data transfer, which is data transfer for all receiving stations on the network, and multicast data transfer, which is data transfer for a specific group of multiple receiving stations. In the case of, when all of the receiving stations that are the data transfer partners return ACK frames to the transmitting station, the number of ACK frames increases in accordance with the number of data transfer partners, and as a result, the network traffic becomes There is a problem that it increases.
[0011]
Therefore, in order to realize highly reliable multicast data transfer and reduce the number of ACK frames as much as possible, the above-mentioned ACK frame return method is examined.
[0012]
First, the method of returning an ACK frame by the MAC layer in the LAN system and the method of returning an ACK frame every time all receiving stations receive a multicast data frame, such as the first method in IP multicast, are described above. As described above, there is a problem that the number of ACK frames increases according to the number of receiving stations, and the traffic of the network increases.
[0013]
Further, the second method in IP multicast, that is, a receiving station is arranged in a tree structure, a plurality of ACK frames notified from the receiving station as each node are aggregated into one, and notified to an upper node. In the method of finally sending an ACK frame to the transmitting station, when performing wireless communication, data used for communication between certain receiving stations does not use a dedicated channel, but all data use the same channel. Therefore, there is no distinction between integrating the ACK frame at each node and passing the ACK frame to an upper node, and passing the ACK frame from each node directly to the transmitting station. Therefore, in this case as well, an increase in network traffic is unavoidable.
[0014]
In the third method of IP multicast, that is, a method of notifying a transmitting station or a nearby node capable of retransmission of NAK data indicating that a receiving station has failed to receive a packet, performs wireless communication. In this case, it is not guaranteed whether or not the NACK frame itself has arrived at the transmitting station, so that it is not guaranteed that the transmitted frame has arrived correctly just because the transmitting station has not received the NACK frame. Therefore, in this case, the reliability of data cannot be guaranteed.
[0015]
SUMMARY OF THE INVENTION An object of the present invention is to provide a receiving station that needs to receive data accurately when performing multicast data transfer or the like in a communication system such as a wireless or wired LAN system or an AV transmission system. An object of the present invention is to suppress an increase in a communication amount due to an ACK frame or the like while securing the communication amount.
[0016]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a data transfer method according to the present invention is a data transfer method using a communication system including a plurality of communication devices and capable of transferring data between the plurality of communication devices via a communication network. A data transfer method for performing data transfer from a transmitting communication device to a plurality of receiving communication devices via the communication network, wherein each of the receiving communication devices receives data via the communication network; Acknowledgment data notifying that the data has been received, a reply process for returning via the communication network can be executed, and whether or not to perform the reply process is determined for each of the receiving communication devices. A setting step of setting by a setting unit of a receiving communication device, a transmitting step of transmitting data through the communication network, and transmitting the data transmitted by the transmitting communication device. A receiving step of receiving by the receiving communication device, and determining means of each of the receiving communication devices receiving the data transmitted by the transmitting communication device perform the return processing based on the setting of the setting device of the receiving communication device. And a determining step of determining whether or not to perform.
[0017]
According to the above method, it is possible to set, for each receiving communication device, a reply of acknowledgment data such as an ACK frame from the receiving communication device to data transmitted from the transmitting communication device.
[0018]
Therefore, for example, even when the communication network is based on wireless communication and the same data is transmitted from the transmitting communication device to the plurality of receiving communication devices by multicast data in the same band, a reply is received from the receiving communication device. The amount of acknowledgment data can be changed as needed. As a result, by transmitting acknowledgment data to a receiving-side communication device that needs to receive data reliably, data transfer can be ensured, and the need to reliably receive data can be improved. By not returning the acknowledgment data to the low-reception-side communication device, it is possible to suppress an increase in the amount of communication in the communication network and to smoothly transfer data that should be transferred.
[0019]
For example, in a communication system in which a transmitting-side communication device transmits an AV stream as multicast data and a receiving-side communication device includes a recording medium such as a DVD-R and a display medium such as a liquid crystal television, a comparison is made between a recording medium and a display medium. In some cases, a recording medium must receive data more reliably than a display medium. In such a case, when the above method is applied, the confirmation response data is returned to the recording medium, so that the recording medium can receive accurate data, and the confirmation medium can be transmitted to the display medium. By preventing the response data from being returned, it is possible to suppress an increase in the communication amount due to the acknowledgment data.
[0020]
Note that, in the above method, it is possible to make settings such that the acknowledgment data is returned to all the receiving communication devices, or the acknowledgment data is not returned to all the receiving communication devices. Consistency with data transfer requesting acknowledgment data from the transmission destination (such as normal multicast data transfer using a wireless LAN) and data transfer not accepting acknowledgment data at all (such as normal IP multicast data transfer) can be achieved. it can.
[0021]
In the data transfer method of the present invention, the communication system includes a communication management device having a storage unit that stores return permission / prohibition information that determines whether or not each of the reception-side communication devices performs the return process. The notifying means of the communication management device further includes a notifying step of notifying each of the receiving communication devices whether or not to perform the reply process in the receiving communication device, based on the reply availability information, In the setting step, it is preferable that the setting unit performs the setting based on the content notified by the notification step.
[0022]
According to the above method, it is possible to centrally manage whether or not to cause a plurality of receiving-side communication devices to execute a reply process by the communication management device. Thereby, it is possible to easily set or change whether or not to cause a plurality of receiving communication devices to execute the reply process.
[0023]
The data transfer method of the present invention further comprises an inquiry step in which the inquiry means of each of the receiving communication devices inquires of the communication management device whether or not to perform the reply processing in the receiving communication device. In the step, it is preferable that the notifying unit performs the notification to the receiving communication device that has queried in the inquiry step.
[0024]
According to the above method, it is possible to set whether or not to cause the communication side device to execute the reply process in response to a request from each communication side device. For example, when the communication apparatuses are individually activated, an inquiry can be made at the time of activation of each communication apparatus, and the above setting can be performed.
[0025]
In the data transfer method according to the present invention, the reply permission / non-permission information classifies the plurality of receiving-side communication devices into a plurality of groups, and determines whether or not to cause each of the receiving-side communication devices to execute a reply process for each of the groups. Is desirable.
[0026]
In the above method, the plurality of receiving communication apparatuses are classified into a plurality of groups, and whether or not to execute the reply process is determined for each group. Here, “determined for each group” means that for the receiving-side communication devices belonging to one group, whether to execute the reply process is unified.
[0027]
If it is set for each receiving communication device whether or not to execute the reply process, the setting and changing operations become complicated as the number of receiving communication devices increases. On the other hand, the plurality of receiving communication apparatuses are classified into a plurality of various groups in advance, and whether or not to execute the reply process is determined for each group. Can be suppressed.
[0028]
As a method of classifying the plurality of receiving-side communication devices into a plurality of groups, for example, the plurality of receiving-side communication devices can be classified into the plurality of groups based on a priority order for executing the reply process. .
[0029]
In order to classify the communication devices into groups based on the priority, for example, the receiving communication devices having the same priority can be classified into the same group. As a result, the acknowledgment data is returned only to the group of the receiving communication apparatuses having the specific priority, and the reliability of data reception of the group can be improved. In addition, for example, receiving-side communication devices having a certain priority or higher can be classified into the same group. As a result, the acknowledgment data is returned only to the group of the receiving communication devices having the specific high priority, and the reliability of data reception of the group can be improved. Conversely, for example, receiving-side communication devices having a certain priority or lower may be classified into the same group. As a result, the acknowledgment data is not returned to the group of the receiving communication apparatuses having the specific low priority, and the communication amount can be reduced.
[0030]
In the data transfer method according to the present invention, the reply propriety information classifies the plurality of receiving communication devices into a plurality of groups based on an attribute of each receiving communication device, and executes a reply process to each of the receiving communication devices. It is determined for each of the groups whether or not to make it, based on the reply availability information and the attributes of each of the receiving communication devices, to which group the receiving communication device belongs to the group of the communication management device A group discriminating step for discriminating means, and a recognition step for recognizing the communication managing device, based on a result of the group discriminating step, for recognizing whether or not the receiving communication device should execute the reply process. Preferably, in the notifying step, the notifying unit notifies a recognition result by the recognizing step.
[0031]
In the above method, the plurality of receiving communication devices are classified into a plurality of groups based on the attributes of each receiving communication device. Then, the group to which the receiving communication device belongs is determined based on the reply permission / inhibition information and the attribute of each receiving communication device, and the reception is determined based on whether the group is set to execute the reply process. The communication device recognizes whether or not to make the communication device execute the reply process. Therefore, by sending data indicating its own attribute from the receiving communication device to the communication management device, the communication management device determines which group the receiving communication device belongs to based on the data, It is possible to recognize whether or not to make the receiving side communication device perform a reply process.
[0032]
Note that the attribute may be one or more types of attributes. In particular, it is desirable to classify a plurality of receiving communication devices into a plurality of groups based on a plurality of attributes of each receiving communication device. In this case, one receiving communication device may belong to two or more groups. As described above, when one receiving communication device belongs to two or more groups, the criterion for determining whether or not to transmit acknowledgment data to the receiving communication device increases. Therefore, it is possible to select one of the attributes of the receiving communication device and make a determination based on the attribute, thereby enabling more various determinations.
[0033]
It is preferable that the data transfer method of the present invention further include a rewriting step in which the rewriting means of the communication management device rewrites the reply availability information.
[0034]
In the above-described method, it is possible to change whether or not to cause each receiving communication device to execute a reply process by rewriting the reply permission / prohibition information. Thus, while suppressing an increase in the amount of communication, the receiving communication device that executes the reply process is not limited to the specific receiving communication device, and the reply process is executed by the receiving communication device selected according to the situation. be able to. Therefore, for example, it is possible to change the receiving communication device that executes the reply process according to the data transmitted by the transmitting communication device.
[0035]
Further, by performing the above rewriting at a predetermined timing, it is possible to cause various receiving-side communication devices to sequentially execute reply processing, and it is also possible to manage reception states in various receiving-side communication devices.
[0036]
In the data transfer method according to the present invention, the reply permission / prohibition information includes classifying the plurality of receiving communication devices into a plurality of groups, and performing the reply processing on behalf of the receiving communication devices belonging to the group for each group. It is preferable to determine a representative communication device that performs the above-described processing, and determine whether or not to cause each of the receiving-side communication devices to execute a reply process for each of the groups.
[0037]
In the above method, for example, when there are a plurality of groups classified for each place, if the receiving communication device that manages each group is set as the representative communication device and the representative communication device is returned on behalf of the acknowledgment data, the management can be performed. It is possible to reliably confirm the communication state in the representative communication device performing the communication.
[0038]
The data transfer method of the present invention further includes a changing step of changing the representative communication device of each group in the reply permission / non-permission information to another receiving communication device belonging to each group by a change unit of the communication management device. It is desirable.
[0039]
In the above method, since the representative communication device of each group can be changed, it is possible to know the reception state of the receiving communication device other than the specific receiving communication device.
[0040]
In the data transfer method according to the present invention, it is preferable that the communication management device is provided in the transmission-side communication device.
[0041]
In the above method, since the communication management device is provided in the transmission-side communication device, the transmission-side communication device can easily grasp from which reception-side communication device the acknowledgment data is returned. This makes it possible for the transmitting communication device to easily determine whether retransmission is necessary.
[0042]
A communication system according to the present invention is a communication system for performing data transfer via a communication network, wherein, when data is received via the communication network, acknowledgment data for notifying that the data has been received is transmitted to the communication network. A plurality of receiving communication devices capable of executing a reply process for replying via a communication device, and a communication management device that determines whether or not to cause each of the receiving communication devices to execute the reply process; A storage unit configured to store, in each of the receiving-side communication devices, reply-possibility information that determines whether or not to execute the reply processing; and, based on the reply-possibility information, performing the reply processing to each of the reception-side communication devices. And a notifying unit for notifying each of the communication devices of a recognition result by the recognizing unit.
[0043]
In the above communication system, the data transfer method by the communication system including the above communication management device can be executed, and the above effects can be obtained.
[0044]
The communication system of the present invention further includes a transmitting communication device that transmits data to the receiving communication device via the communication network, and the communication management device is provided in the transmitting communication device. Is desirable.
[0045]
In the above configuration, since the communication management device is provided in the transmission-side communication device, the transmission-side communication device can easily grasp from which reception-side communication device the acknowledgment data is returned. This makes it possible for the transmitting communication device to easily determine whether retransmission is necessary.
[0046]
The communication management device of the present invention is a communication management device for managing a communication system capable of transferring data from a transmission-side communication device to a plurality of reception-side communication devices via a communication network, wherein each of the reception-side communication devices includes: When receiving data via a network, it is possible to execute a reply process for returning, via the communication network, acknowledgment data for notifying that the data has been received, wherein each of the receiving-side communication devices Storage means for storing reply permission / non-permission information defining whether or not to execute the reply processing, and recognizing whether or not to allow each of the receiving communication devices to execute the reply processing based on the reply permission / prohibition information It is characterized by comprising a recognizing means, and a notifying means for notifying each of the communication devices of a recognition result by the recognizing means.
[0047]
The communication management device described above can be used for the communication system, and can obtain the above-described effects.
[0048]
It is preferable that the communication management device of the present invention is provided in the transmission-side communication device.
[0049]
In the above configuration, since the communication management device is provided in the transmission-side communication device, the transmission-side communication device can easily grasp from which reception-side communication device the acknowledgment data is returned. This makes it possible for the transmitting communication device to easily determine whether retransmission is necessary.
[0050]
The communication management program according to the present invention causes a computer to function as each unit of the communication management device. Further, a recording medium of the present invention records the above communication management program.
[0051]
BEST MODE FOR CARRYING OUT THE INVENTION
One embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, the description will be given on the premise of a wireless LAN system. However, the present invention is not limited to the wireless LAN system, but can be applied to a wired LAN system. In addition, the present invention is not limited to a LAN system, and can be applied to an AV transmission system that transmits and receives wireless or wired AV (Audio Visual) data.
[0052]
There are situations in which real-time images are projected on a TV, a projector, or the like in a plurality of rooms at different locations in a lecture or a seminar. As described above, when one image is displayed on a plurality of display devices via a network, it is reasonable to distribute the image data by multicast data transfer. This is because the multicast data transfer does not waste network bandwidth.
[0053]
In the case of performing such a multicast data transfer, when the data transfer destination includes a display device and a recording device such as a VCR or a DVD deck, the data transfer is similarly performed to the display device and the recording device. It is not preferable. This is because even if a part of the data transferred to the display device is broken, the displayed image is only slightly disturbed. This is because data is recorded and accurate recording cannot be left.
[0054]
In order to avoid this, it is conceivable to transfer the data to the video device by multicast and to the recording device by unicast to maintain the reliability of the data to be recorded. However, transferring data of the same content as separate data wastes network bandwidth.
[0055]
Such a problem may occur when video and audio are recorded as minutes of a video conference or a telephone conference in a plurality of rooms.
[0056]
In addition, when a plurality of video devices such as TVs are used, and HDTV (High-Definition Television) data is transferred to the video devices and the video is displayed on each video device, the same problem as described above occurs. There is. In other words, when normal video quality is acceptable for some video devices, transferring data by unicast to all video devices means transferring the same data as different data. Bandwidth is wasted.
[0057]
In this way, when transferring the same data via the network, a group of receiving stations that require high reliability for the received data and a group of receiving stations that do not require high reliability for the received data are considered. There are situations where groups coexist.
[0058]
Therefore, in the present embodiment, an ACK frame (acknowledgement data) notifying that the receiving station has received the data is returned for each group of the receiving stations while transferring the data by the multicast data transfer.
[0059]
(overall structure)
FIG. 1 is a diagram illustrating an overall configuration of a wireless LAN system 1 (communication system) according to the present embodiment. The wireless LAN system 1 includes a transmitting station 100, a receiving station 200, a receiving station 201, a non-receiving station 202, and a receiving station 203.
[0060]
Note that the transmitting station 100, the receiving station 200, the receiving station 201, the non-receiving station 202, and the receiving station 203 are all stations of the wireless LAN system 1, but here it is assumed that certain data is transferred by multicast data. In this case, the station on the transmitting side is the transmitting station 100 (transmitting side communication device), the stations on the receiving side are the receiving station 200 (receiving side communication device), the receiving station 201 (the receiving side communication device), and the receiving station 203. (Receiving communication device), a station not involved in this data transfer is referred to as a non-receiving station 202.
[0061]
Here, the receiving station 200 and the receiving station 201 belong to the receiving station group 300 classified according to the installation location of each station, and the receiving station 200 is a reception representative station of the group. The receiving station 203 belongs to a receiving station group 301 classified according to the installation location of the station, and the receiving station 203 is a representative receiving station of the group. Hereinafter, the receiving station 200 and the receiving station 203 may be referred to as a representative receiving station 200 and a representative receiving station 203, respectively.
[0062]
The receiving station 200 and the receiving station 203 belong to a receiving station group 302 classified as a representative receiving station. Further, it is assumed that the receiving station 200, the receiving station 201, and the receiving station 203 belong to the receiving station group 303 classified according to the classification of receiving multicast data.
[0063]
(Transfer state)
FIG. 2 is a diagram showing the relationship of frames transferred when data is transferred from the transmitting station 100 to the receiving stations 200 to 203 by multicast in the wireless LAN system 1 of FIG. 1 over time. In FIG. 2, the time elapses vertically downward.
[0064]
FIG. 2 assumes a case where multicast data is transmitted from transmitting station 100 to receiving groups 300 and 301. FIG. 2 assumes a case where only the receiving stations belonging to receiving group 300 are set to return an ACK frame.
[0065]
The transmitting station 100 transmits a multicast data frame 400. Then, the receiving representative station 200 and the receiving station 201 of the receiving station group 300 and the receiving representative station 203 of the receiving group 301 receive the multicast data frame 400, and the non-receiving station 202 does not receive the multicast data frame 400.
[0066]
The reception representative station 200 and the reception station 201 that have received the multicast data frame 400 return ACK frames 410 and 411, respectively. Other receiving representative stations 203 and non-receiving stations 202 do not return ACK frames.
[0067]
Then, transmitting station 100 confirms that transmission of multicast data frame 400 has been completed by receiving ACK frames 410 and 411 returned by receiving representative station 200 and receiving station 201.
[0068]
Next, the transmitting station 100 transmits the multicast data frame 401. At this time, it is assumed that only the reception representative station 200 receives the multicast data frame 401, and the reception station 201 and the reception representative station 203 cannot receive the multicast data frame 401.
[0069]
Then, the receiving representative station 200 returns the ACK frame 412, but the receiving station 201 does not return the ACK frame since the receiving station 201 has not received the multicast data frame 401.
[0070]
In this case, since the transmitting station 100 does not receive the ACK frame from the receiving station 201 to be received, the transmitting station 100 determines that the receiving station 201 could not receive the multicast data frame 401, and determines that the multicast data frame for retransmission (the multicast retransmission frame). ) 420 is transmitted.
[0071]
This time, it is assumed that the receiving representative station 200, the receiving station 201, and the receiving representative station 203 have received the multicast retransmission frame 420. At this time, the reception representative station 200 and the reception station 201 return ACK frames 413 and 414, respectively.
[0072]
Then, transmitting station 100 confirms that transmission of multicast retransmission frame 420 has been completed by receiving ACK frames 413 and 414 returned by receiving station 200 and receiving station 201.
[0073]
If a state in which no ACK frame is returned from the receiving station 201 continues a plurality of times, the transmitting station 100 terminates abnormally because the multicast data frame 401 could not be transmitted, and transmits the next multicast data frame.
[0074]
By repeating the above processing, multicast data transfer from the transmitting station 100 is performed.
[0075]
FIG. 3 is a diagram showing, with time, the relationship of frames transferred when data is transferred from the transmitting station 100 to the receiving stations 200 to 203 by multicast in the wireless LAN system 1 of FIG. On the other hand, the case where the group that returns the ACK frame is changed from the receiving station group 300 to the receiving station group 302 is shown. As shown in FIG. 1, the receiving station group 302 includes a receiving representative station 200 and a receiving representative station 203.
[0076]
The transmitting station 100 transmits a multicast data frame 500. Then, the receiving representative stations 200 and 201 of the receiving station group 300 and the receiving representative station 203 of the receiving group 301 receive the multicast data frame 500, and the non-receiving station 202 does not receive the multicast data frame 500.
[0077]
The reception representative stations 200 and 203 that have received the multicast data frame 500 return ACK frames 510 and 511, respectively. Other receiving stations 201 and non-receiving stations 202 do not return ACK frames.
[0078]
Then, transmitting station 100 confirms that transmission of multicast data frame 500 has been completed by receiving ACK frames 510 and 511 returned by reception representative stations 200 and 203.
[0079]
Next, the transmitting station 100 transmits the multicast data frame 501. At this time, it is assumed that only the reception representative station 200 receives the multicast data frame 501, and the reception station 201 and the reception representative station 203 cannot receive the multicast data frame 501.
[0080]
Then, the reception representative station 200 returns an ACK frame 512, but does not return an ACK frame since the reception representative station 203 has not received the multicast data frame 501.
[0081]
In this case, since the transmitting station 100 does not receive the ACK frame from the receiving representative station 203 to be received, the transmitting station 100 determines that the receiving representative station 203 has failed to receive the multicast data frame 501, and determines that the multicast data frame (multicast Retransmission frame) 520 is transmitted.
[0082]
This time, it is assumed that the reception representative station 200, the reception station 201, and the reception representative station 203 have received the multicast retransmission frame 520. At this time, the reception representative stations 200 and 203 return ACK frames 513 and 514, respectively.
[0083]
Then, transmitting station 100 confirms that transmission of multicast retransmission frame 520 has been completed by receiving ACK frames 513 and 514 returned from receiving representative stations 200 and 203.
[0084]
If the state where the ACK frame is not returned from the reception representative station 203 continues a plurality of times, the transmitting station 100 ends abnormally because the multicast data frame 501 cannot be transmitted, and transmits the next multicast data frame.
[0085]
In the case of FIG. 3, the receiving station 201 is regarded as a receiving station whose data reliability may be low, and does not belong to a group that returns an ACK frame.
[0086]
(Reception station configuration)
FIG. 4 is a block diagram showing a configuration of the receiving station 200 in the wireless LAN system 1 of FIG. The receiving stations 201 and 203 have the same configuration as the receiving station 200.
[0087]
The receiving station 200 includes a receiving unit 11 as a receiving unit for receiving a multicast data frame, a packet analyzing unit 12 as a packet analyzing unit, a packet selecting unit 13 as a packet selecting unit, a buffer 14, and an ACK frame controlling unit. An ACK control unit 15 as a (determination unit), an ACK generation unit 16 that generates an ACK frame based on an instruction from the ACK control unit 15, a transmission unit 17 as a transmission unit, and two or more transmission / reception units The antenna 18 includes a setting unit 19 as a setting unit for setting for ACK frame control, and an inquiry unit 20 as an inquiry unit for inquiring about the setting for ACK frame control.
[0088]
The packet analysis unit 12 analyzes the packet length and the like of the multicast data frame received by the reception unit 11, and determines whether or not the multicast data frame has been correctly received. After that, the received multicast data frame is sent to the buffer 14 and the ACK control unit 15 by the packet selecting unit 13. The ACK control unit 15 determines whether or not the own station is a receiving station that returns an ACK frame based on the setting of the setting unit 19, and generates an ACK when the own station is a receiving station that returns an ACK frame. An ACK frame return instruction is issued to the unit 16. The ACK generation unit 16 creates an ACK frame according to the instruction of the ACK control unit 15 and sends the ACK frame to the transmission unit 17. The transmitting unit 17 returns the ACK frame transmitted from the ACK generating unit 16 to the transmitting station 100 that is the transmitting station of the multicast data frame. The multicast data frame sent to the buffer 14 is used for processing the multicast data in the receiving station 200.
[0089]
The setting unit 19 and the inquiry unit 20 will be further described later.
[0090]
(Processing flow of receiving station)
FIG. 5 is a flowchart showing a flow of processing when the receiving station 200 in the wireless LAN system 1 of FIG. 1 receives a multicast data frame. Note that the same processing is performed in the receiving stations 201 and 203.
[0091]
When the receiving station 200 receives the multicast data frame from the transmitting station 100 by the receiving unit 11 (receiving step S11), the packet analyzing unit 12 determines whether or not the multicast data frame has been correctly received (S12). If it has not been received, it waits until the next multicast data frame is received, and if it has received it, it sends the multicast data frame received by packet selector 13 to buffer 14 and ACK controller 15. The ACK control unit 15 determines whether or not the receiving station 200 is a receiving station that returns an ACK frame, based on the setting of the setting unit 19 described later (determination step S13). If the receiving station 200 is a receiving station that returns an ACK frame, the ACK generating unit 16 generates an ACK frame and returns the ACK frame from the transmitting unit 17 to the transmitting station 100 (S14, reply processing). If the receiving station 200 is not a receiving station that returns an ACK frame, the receiving station 200 waits until receiving the next multicast data frame.
[0092]
(Configuration of transmitting station)
FIG. 7 is a block diagram showing a configuration of the transmitting station 100 in the wireless LAN system 1 of FIG.
[0093]
The transmission station 100 stores a data storage unit 31 storing data to be transmitted by multicast data transfer, a transmission unit 32 for transmitting a multicast data frame, a reception unit 33 for receiving an ACK frame, and a ACK frame for reception. It includes an ACK frame management unit 34 for managing, a data transmission control unit 35 for controlling transmission of multicast data frames and retransmission frames, and two or more antennas 36 for receiving or transmitting.
[0094]
The transmitting station 100 includes a communication management device 110 that manages communication of the wireless LAN system 1. In the present embodiment, a case will be described where the communication management apparatus 110 is provided in the transmitting station 100, but the communication management apparatus 110 does not necessarily need to be provided in the transmitting station 100. For example, the communication management apparatus 110 may be provided in one of the receiving stations, an AP (access point) of the wireless LAN system 1, or another station that manages the receiving station. It may be incorporated in the system 1.
[0095]
The communication management device 110 includes a reply permission / non-permission information storage unit 41 (storage unit) that stores reply permission / non-permission information that determines whether or not each reception station returns an ACK frame. A recognizing unit 42 (recognizing unit) for recognizing whether or not to return a frame; a notifying unit 43 (notifying unit) for notifying each receiving station of the recognition result by the recognizing unit 42; Reply permission / prohibition information management unit 44 (rewriting means, change means) for managing permission / prohibition information, and group determination unit 45 (for determining to which group the receiving station belongs based on the reply permission / prohibition information and the attribute of the receiving station) Group determining means) and an inquiry receiving unit 46 for receiving an inquiry from the receiving station.
[0096]
(Processing flow of transmitting station)
FIG. 6 is a flowchart showing the flow of processing when transmitting a multicast data frame in transmitting station 100 in wireless LAN system 1 in FIG.
[0097]
The transmitting station 100 transmits a multicast data frame by the transmitting unit 32 (transmitting step S21), and determines whether or not ACK frames have been received from all receiving stations that return ACK frames within a predetermined time. The determination is made by S (S22). When transmitting station 100 receives ACK frames from all receiving stations that return ACK frames, it ends the transmission process of the multicast data frame and waits for transmission of the next multicast data frame. If the transmitting station 100 has not received ACK frames from all receiving stations that return ACK frames, the data transmission control unit 35 determines whether the multicast data frame has been retransmitted a predetermined number of times or more (S23). If the number is less than the predetermined number, the multicast data frame is retransmitted (S24). If the number is more than the predetermined number, the multicast data frame is not retransmitted and ends abnormally and waits. If the multicast data frame has been retransmitted, the ACK frame management unit 34 determines whether the transmitting station 100 has received an ACK frame for the retransmitted frame from all receiving stations that return the ACK frame (S25). When the transmitting station 100 receives ACK frames from all receiving stations that return ACK frames, it determines that the transmission of the multicast data frame has been completed normally and waits for transmission of the next multicast data frame. If the transmitting station 100 has not received ACK frames from all receiving stations that return ACK frames, the process from step S23 is repeated.
[0098]
The retransmission frame for the receiving station that has not returned the ACK frame may be unicast data for the receiving station.
[0099]
Regarding the number of retransmissions performed by the transmitting station 100, whether retransmission is repeated indefinitely or whether retransmission is stopped at a fixed number of times may be determined according to the priority of the receiving station.
[0100]
Further, when the receiving station that needs to return the ACK data is a recording medium such as a DVD, or when retransmission data continues a plurality of times, the DVD or other recording medium may be temporarily stopped.
[0101]
(Setting of ACK frame reply availability)
FIG. 8 is a diagram showing a relationship of frames transferred when setting whether or not to return an ACK frame to the receiving station in the wireless LAN system 1 of FIG. In FIG. 8, time elapses vertically downward. 8 assumes that only the receiving stations belonging to the receiving station group 300 in FIG. 1 return an ACK frame, and sets whether or not to return the ACK frame for the receiving stations 200 and 203. The steps to be performed are shown. In FIG. 8, the receiving station 201 and the non-receiving station 202 are omitted, and ACK frames for a registration frame and a registration response frame described below are omitted.
[0102]
FIG. 9 is a flowchart showing a procedure for setting whether or not to return an ACK frame to the receiving station in the wireless LAN system 1 of FIG.
[0103]
First, the receiving stations 200 and 203 receive the multicast data frame 600 transmitted by the transmitting station 100 (S31) after the system activation of their own stations (S32).
[0104]
The receiving station 200 transmits to the transmitting station 100 a registration frame 610 having a field indicating that an ACK frame is desired to be returned for the multicast data frame constituting the multicast data and a field indicating the attribute of the receiving station 200 (attribute field). Is transmitted to the server (S33). This step S33 is an inquiry step performed by the inquiry unit 20 of the receiving station 200, and inquiring of the communication management apparatus 110 whether or not the receiving station 200 will return an ACK frame in the future.
[0105]
The communication management device 110 that has received the registration frame 610 at the inquiry receiving unit 46 determines which group the receiving station 200 belongs to based on the attribute field of the registration frame 610 transmitted by the receiving station 200 by the group determination unit 45. Is determined (group determination step S34). At the time of this determination, information regarding the classification of the group based on the attribute of each receiving station stored as the reply availability information is referred to.
[0106]
Then, based on the determination result by the group determination unit 45, the recognition unit 42 recognizes that the receiving station 200 is the receiving station of the receiving station group 300 that returns the ACK frame (recognition step S35).
[0107]
Thereby, the notification unit 43 transmits the registration response frame 620 including the information for causing the receiving station 200 to return the ACK frame (notification step S36).
[0108]
Receiving station 200 receives registration response frame 620 at inquiry section 20 to know that it is the receiving station that returns the ACK frame, and setting section 19 returns the ACK frame. Performs the setting (setting step S37). Therefore, the receiving station 200 then transmits an ACK frame in response to receiving the multicast data frame from the transmitting station 100.
[0109]
When the setting of another receiving station is performed (S38), the processing from step S33 is repeated. When the setting of another receiving station is not performed (S38), the transmitting station shown in FIG. The transmission processing is performed, and the reception processing illustrated in FIG. 5 is performed in the receiving station.
[0110]
The receiving station 203 performs substantially the same processing as the receiving station 200. First, the receiving station 203 transmits a registration frame 611 having a field indicating that an ACK frame is desired to be transmitted for the multicast data frame constituting the multicast data and a field (attribute field) indicating the attribute of the receiving station 203. 100 is transmitted (S33).
[0111]
The communication management apparatus 110 that has received the registration frame 611 at the inquiry receiving unit 46 determines which group the receiving station 203 belongs to based on the attribute field of the registration frame 611 transmitted by the receiving station 203 by the group determination unit 45. (S34), and recognizes that the receiving station is not the receiving station of the receiving station group 300 that returns the ACK frame (recognizes that the receiving station belongs to the receiving station group 301 and the receiving station group 302 that does not return the ACK frame).
[0112]
Thereby, the notification unit 43 transmits the registration response frame 621 including information for preventing the ACK frame from being returned to the receiving station 203 (S36).
[0113]
By receiving the registration response frame 621, the receiving station 203 can know that it is not the receiving station that returns the ACK frame, and the setting unit 19 performs the setting so as not to return the ACK frame (S37). ). Therefore, receiving station 203 does not subsequently transmit an ACK frame in response to receiving the multicast data frame from transmitting station 100.
[0114]
By the above processing, after that, even if the transmitting station 100 transmits the multicast frame 601 and the receiving stations 200 and 203 receive it, only the receiving station 200 returns an ACK frame. In addition, in step S22 of FIG. 6, transmitting station 100 receives the ACK frame returned by receiving station 200, and thus determines that ACK frames have been received from all receiving stations that return the ACK frame. .
[0115]
Note that the reply propriety information stored in the reply propriety information storage section 41 may be rewritten by the reply propriety information management section 44 (rewriting means) at a predetermined timing. That is, during the transmission process of FIG. 6 and the reception process of FIG. 5, a rewrite step by the reply permission / prohibition information management unit 44 may be inserted to change the group of receiving stations that return the ACK frame. At this time, the processing of FIG. 9 is repeated.
[0116]
Thereby, while suppressing an increase in the communication amount, the receiving station to which the ACK frame is returned is not limited to a specific receiving station, but is selected according to the situation (for example, according to data transmitted by the transmitting station). Can return an ACK frame.
[0117]
Note that the timing for inserting the rewriting step may be after the receiving station has received a fixed number of frames, may be after the receiving station has received a random number of frames, May be transmitted, or the transmitting station may transmit a random number of frames.
[0118]
As described above, the communication management device 110 does not necessarily need to be provided in the transmitting station 100, but is preferably provided in the transmitting station 100. Since the communication management apparatus 110 is provided in the transmitting station 100, the transmitting station 100 can easily grasp from which receiving station the ACK frame is returned. This makes it possible for transmission station 100 to easily determine whether retransmission is necessary or not.
[0119]
The communication management device 110 can be configured based on a general-purpose computer such as a personal computer. That is, the communication management apparatus 110 includes a CPU (central processing unit) that executes instructions of a program for realizing each function, a ROM (read only memory) storing boot logic, and a RAM (random access memory) that expands the program. , A storage device (recording medium) such as a hard disk and a ROM for storing the programs and various databases, input devices such as a keyboard and a mouse, output devices such as a monitor (LCD and CRT), speakers, and a network connection for connection to an external network Devices (communication devices) may be connected to each other by an internal bus. In this case, the functions of the communication management device 110 are realized by expanding the program stored in the storage device into the RAM as necessary and executing the program by the CPU.
[0120]
Another object of the present invention is to provide a computer-readable recording medium storing a program code (executable program, intermediate code program, source program) of a communication management program which is software for realizing the above-described functions. It can also be achieved by supplying the program to a device and causing a computer (or CPU or MPU) of the system or the device to read and execute the program code recorded on the recording medium. In this case, the program code itself read from the recording medium realizes the above-described function, and the recording medium on which the program code is recorded constitutes the present invention.
[0121]
Note that the method of classifying the groups of the receiving stations may be based on the priority of returning the ACK frame. For example, receiving stations having the same priority can be classified into the same group. Further, for example, receiving stations having a certain priority or higher can be classified into the same group. Thus, an ACK frame can be returned only to a group of receiving stations having a specific high priority, and the reliability of data reception of that group can be improved. Conversely, for example, receiving stations with a certain priority or lower may be classified into the same group. As a result, an ACK frame is not returned to a group of receiving stations having a specific low priority, so that the amount of communication can be reduced.
[0122]
Further, priorities of the receiving stations may be determined after investigating how accurately each receiving station can receive before the transmitting station transmits the multicast data frame.
[0123]
In the data transfer method of the present invention as described above, it is possible to set, for each receiving station, a reply of the ACK frame from the receiving stations 200, 201, and 203 to the data transmitted from the transmitting station 100.
[0124]
Therefore, even when the same data is transmitted from the transmitting station 100 to the plurality of receiving stations 200, 201, and 203 in the same band by multicast data transmission in the wireless LAN system 1, the receiving stations 200, 201, and 203 reply. The amount of ACK frames can be changed as needed. As a result, by transmitting an ACK frame to a receiving station that needs to receive data reliably, data transfer can be ensured, and a receiving station that does not need to receive data reliably can be achieved. By not sending back an ACK frame, it is possible to suppress an increase in the amount of communication in the communication network and to smoothly transfer data that should be transferred.
[0125]
In the above method, since it is possible to set an ACK frame to be returned to all the receiving stations or not to return the ACK frame to all the receiving stations, the ACK frame from all the receiving stations can be set. , And data transfer that does not accept ACK frames at all (such as normal IP multicast data transfer).
[0126]
Further, by combining a mechanism for restoring data such as FEC in addition to the present invention, more reliable multicast data transfer becomes possible.
[0127]
(Reception representative station)
In the above description, a case has been described in which the transmitting station 100 performs all retransmission processing. However, within each receiving station group (the receiving station groups 300 and 301, etc.), the receiving representative station (receiving representative station) of each receiving station group is included. 200, 203, etc.) may perform retransmission processing to other receiving stations belonging to the receiving station group.
[0128]
In this case, the reply propriety information stored in the reply propriety information storage unit 41 of the communication management device 110 classifies the plurality of receiving stations into a plurality of receiving station groups, and assigns each receiving station group to the receiving station group. A representative receiving station (representative communication device) that performs the reply process on behalf of the receiving station to which the receiving station belongs may be determined, and whether or not each of the representative receiving stations may perform the reply process may be determined for each receiving station group.
[0129]
Also, the ACK frame management unit 34 of the transmitting station 100 confirms that the ACK frame has been received from the receiving representative station of the receiving station group that returns the ACK frame, thereby deeming that the transmission processing of the multicast data frame has been completed. I can do it. At this time, if the receiving station other than the receiving representative station cannot correctly receive the multicast frame, the receiving station shall request retransmission to the receiving representative station of the receiving station group to which the receiving station belongs. It is assumed that the receiving representative station performs a process of retransmitting the multicast data frame from the transmitting station 100 received by the receiving station in response to the request.
[0130]
This method is particularly useful in a system in which even if the receiving representative station of the receiving station group can correctly receive data, the receiving representative station can appropriately retransmit to other receiving stations of the receiving station group. For example, in a system in which the transmitting station 100 and each receiving station transmit and receive data wirelessly, and in each receiving station group, the receiving representative station and other receiving stations are connected by wire, It is conceivable that the receiving representative station performs data retransmission to another receiving station via a wire by the method described above. In this case, by leaving the retransmission to the reception representative station, the load on the transmitting station 100 can be reduced, and the wireless band for retransmission used by the transmitting station 100 can be reduced.
[0131]
In addition, the reply propriety information management unit 44 (change means) of the communication management apparatus 110 changes the reply propriety information so that the reception representative station in each reception station group can be changed to another reception station in the reception station group. It may be. That is, in the course of the transmission processing of FIG. 6 and the reception processing of FIG. 5, a change step by the reply permission / prohibition information management unit 44 may be inserted to change the reception representative station. At this time, the processing of FIG. 9 is repeated.
[0132]
As a result, the representative receiving station changes within the receiving station group, and the transmitting station 100 can sequentially know the receiving state at each receiving station of each receiving station group based on the response status of the ACK frame. Become like Therefore, it is possible to take measures against a receiving station having a poor receiving condition. For example, when a receiving station having a poor reception state becomes a receiving representative station, the receiving representative station can notify the transmitting station 100 so that data can be more accurately received (for example, by wireless communication). For data transmission / reception, a request to increase the power of the radio wave is notified). It is also conceivable that the receiving station having the best receiving condition is set as the receiving representative station.
[0133]
(Supplement)
The present invention enables receiving stations to communicate with each other by wire, or enables communication by changing a wireless channel, so that a transmitting station can receive data from a receiving station that can receive data correctly instead of retransmitting. It is also conceivable to exchange the data with a receiving station that failed.
[0134]
When the receiving station returns ACK data for a plurality of multicast data frames, and there is a receiving station that returns an ACK frame for the same multicast data frame, negotiations are performed between the receiving stations, and for the ACK frame for the same multicast data frame, It is also possible not to reply.
[0135]
When communication is performed by wire, when data confirmation is necessary, an ACK frame is not returned when reception is correctly performed, but a NAK frame is returned when reception fails. The frame may be retransmitted when received.
[0136]
When communication is performed wirelessly, the priority of the receiving station increases as the distance from the transmitting station increases, so that an ACK frame is returned preferentially to a receiving station that is far away. It may be.
[0137]
In addition, the same frame is normally retransmitted only up to a certain number of times for a receiving station having a certain priority or higher according to the priority assigned to the receiving station group. The retransmission frame may be continuously retransmitted.
[0138]
The classification method includes the location of the receiving station, the device type of the receiving station, the capability of the receiving station, the person using the receiving station, the priority of the receiving station, and whether or not the receiving station is a representative station. Yes, a classification method combining a plurality of classification methods may be used.
[0139]
【The invention's effect】
As described above, according to the data transfer method of the present invention, each receiving communication device can execute a reply process, and whether or not to perform a reply process is determined for each receiving communication device by setting the receiving communication device. A setting step set by the means, a transmitting step in which the transmitting communication device transmits data via a communication network, a receiving step in which each receiving communication device receives data transmitted by the transmitting communication device, Determining means of each receiving communication device that has received the data transmitted by the communication device, determining whether or not to perform a reply process based on the setting of the setting means of the receiving communication device. is there.
[0140]
According to the above method, it is possible to set, for each receiving communication device, a reply of acknowledgment data such as an ACK frame from the receiving communication device to data transmitted from the transmitting communication device.
[0141]
Therefore, the amount of acknowledgment data returned from the receiving communication device can be changed as needed. As a result, by transmitting acknowledgment data to a receiving-side communication device that needs to receive data reliably, data transfer can be ensured, and the need to reliably receive data can be improved. By not returning the acknowledgment data to the low-reception-side communication device, it is possible to suppress an increase in the amount of communication in the communication network and to smoothly transfer data that should be transferred.
[0142]
In the data transfer method according to the present invention, the communication system includes a communication management device having storage means for storing reply propriety information. On the other hand, it is preferable that the method further includes a notifying step of notifying whether or not the receiving side communication device performs a reply process, and the setting step is performed by the setting means based on the content notified by the notifying step.
[0143]
According to the above method, it is possible to easily set or change whether or not to cause a plurality of receiving communication devices to execute the reply process.
[0144]
The data transfer method of the present invention further includes an inquiry step in which the inquiry means of each receiving communication device inquires of the communication management device whether or not to perform a reply process in the receiving communication device. It is desirable that the notifying unit notifies the receiving side communication device that has made the inquiry in the step.
[0145]
According to the above method, it is possible to set whether or not to cause the communication side device to execute the reply process in response to a request from each communication side device.
[0146]
In the data transfer method of the present invention, the reply permission / prohibition information may classify the plurality of receiving communication devices into a plurality of groups and determine whether each receiving communication device performs the reply process for each group. desirable.
[0147]
According to the above-described method, even if the number of receiving communication devices increases, the complexity of setting and changing can be suppressed.
[0148]
As a method of classifying the plurality of receiving-side communication devices into a plurality of groups, for example, the plurality of receiving-side communication devices can be classified into a plurality of groups based on the priority order for executing the reply process.
[0149]
In the data transfer method according to the present invention, the reply permission / prohibition information may include a step of classifying the plurality of receiving communication devices into a plurality of groups based on an attribute of each receiving communication device, and causing each receiving communication device to execute a reply process. Group is determined for each group, and the group determination means of the communication management device determines which group the communication device of the receiving side belongs to, based on the reply propriety information and the attribute of each communication device of the receiving side. And a recognition step of recognizing the communication management device based on a result of the determination performed by the group determination step. It is desirable that the notification unit notifies the recognition result of the step.
[0150]
In the above method, by transmitting data indicating its own attribute from the receiving communication device to the communication management device, the communication management device determines which group the receiving communication device belongs to based on the data. It is possible to determine and determine whether or not to make the receiving-end communication device perform a reply process.
[0151]
It is preferable that the data transfer method of the present invention further includes a rewriting step in which the rewriting means of the communication management device rewrites the reply propriety information.
[0152]
In the above method, while suppressing an increase in the amount of communication, the reply process is not limited to the specific receiving communication device to execute the reply process, but is sent to the selected receiving communication device according to the situation. Can be executed.
[0153]
In the data transfer method according to the present invention, the reply propriety information may be a representative communication that classifies a plurality of receiving communication devices into a plurality of groups and performs a reply process on behalf of the receiving communication devices belonging to the group for each group. It is desirable that a device is determined and whether or not each receiving communication device performs a reply process is determined for each group.
[0154]
It is preferable that the data transfer method of the present invention further includes a changing step of changing the representative communication device of each group in the reply propriety information to another receiving-side communication device belonging to each group by the change unit of the communication management device.
[0155]
In the data transfer method according to the present invention, it is preferable that the communication management device is provided in the transmitting communication device.
[0156]
In the above method, since the communication management device is provided in the transmission-side communication device, the transmission-side communication device can easily grasp from which reception-side communication device the acknowledgment data is returned. This makes it possible for the transmitting communication device to easily determine whether retransmission is necessary.
[0157]
The communication system of the present invention includes a plurality of receiving-side communication devices capable of executing a reply process, and a communication management device that determines whether or not each receiving-side communication device performs the reply process. Storage means for storing reply permission / non-permission information that determines whether or not each receiving communication device performs a reply process, and recognizes whether or not each receiving communication device performs a reply process based on the reply propriety information. And a notifying unit for notifying each communication device of a recognition result by the recognizing unit.
[0158]
In the above communication system, the data transfer method by the communication system including the above communication management device can be executed, and the above effects can be obtained.
[0159]
It is preferable that the communication system of the present invention further includes a transmitting communication device that transmits data to the receiving communication device via the communication network, and the communication management device is provided in the transmitting communication device.
[0160]
In the above configuration, since the communication management device is provided in the transmission-side communication device, the transmission-side communication device can easily grasp from which reception-side communication device the acknowledgment data is returned. This makes it possible for the transmitting communication device to easily determine whether retransmission is necessary.
[0161]
The communication management device according to the present invention is configured such that each receiving communication device is capable of executing a reply process, and each receiving communication device is configured to store return permission / prohibition information that determines whether or not to execute the reply process. A recognizing means for recognizing whether or not to allow each receiving communication device to execute a reply process based on reply propriety information, and a notifying device for notifying each communication device of a recognition result by the recognizing device. And
[0162]
The communication management device described above can be used for the communication system, and can obtain the above-described effects.
[0163]
It is preferable that the communication management device of the present invention is provided in the transmitting communication device.
[0164]
In the above configuration, since the communication management device is provided in the transmission-side communication device, the transmission-side communication device can easily grasp from which reception-side communication device the acknowledgment data is returned. This makes it possible for the transmitting communication device to easily determine whether retransmission is necessary.
[0165]
The communication management program according to the present invention causes a computer to function as each unit of the communication management device. Further, a recording medium of the present invention records the above communication management program.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an overall configuration of a wireless LAN system according to an embodiment of the present invention.
FIG. 2 is a diagram showing a relationship between frames transferred with time when data is transferred by multicast from a transmitting station to a receiving station in the wireless LAN system of FIG. 1;
FIG. 3 is a diagram showing, with time, the relationship of frames transferred when data is transmitted by multicast from a transmitting station to a receiving station in the wireless LAN system of FIG. 1; Is a drawing showing a case where the group that sends back "?" Has changed.
FIG. 4 is a block diagram showing a configuration of a receiving station in the wireless LAN system of FIG. 1;
5 is a flowchart showing a flow of processing when a receiving station in the wireless LAN system of FIG. 1 receives a multicast data frame.
FIG. 6 is a flowchart showing a flow of processing when a transmitting station in the wireless LAN system of FIG. 1 transmits a multicast data frame.
FIG. 7 is a block diagram illustrating a configuration of a transmitting station in the wireless LAN system of FIG. 1;
FIG. 8 is a diagram showing a relationship of frames transferred when setting whether or not an ACK frame is to be returned to a receiving station in the wireless LAN system of FIG. 1;
9 is a flowchart showing a procedure for setting whether or not to return an ACK frame to a receiving station in the wireless LAN system of FIG. 1;
[Explanation of symbols]
1 Wireless LAN system (communication system)
11 Receiver
12 Packet analysis unit
13 Packet selector
14 Buffer
15 ACK control unit (determination means)
16 ACK generator
17 Transmission section
18 Antenna
19 setting part (setting means)
20 inquiry section (inquiry means)
31 Data storage unit
32 transmission unit
33 Receiver
34 ACK frame management unit
35 Data transmission control unit
36 antenna
41 Reply availability information storage unit (storage means)
42 Recognition unit (recognition means)
43 notification unit (notification means)
44 Reply availability information management unit (rewriting means, changing means)
45 Group discriminator (group discriminating means)
100 transmitting station (transmitting communication device)
110 communication management device
200 receiving station (receiving side communication device, representative communication device)
201 receiving station (receiving side communication device)
202 Non-receiving station
203 receiving station (receiving side communication device, representative communication device)

Claims (16)

A data transfer method by a communication system including a plurality of communication devices and capable of transferring data between the plurality of communication devices via a communication network, the method comprising: transmitting a plurality of reception-side communications from a transmission-side communication device via the communication network. In a data transfer method for transferring data to a device,
When each of the receiving communication devices receives data via the communication network, execution of a reply process for returning, via the communication network, acknowledgment data for notifying that the data has been received is performed. Is possible,
A setting step of setting whether or not to perform the reply process, for each of the receiving communication devices, by a setting unit of the receiving communication device;
A transmitting step in which the transmitting-side communication device transmits data via the communication network;
A receiving step in which each of the receiving communication devices receives the data transmitted by the transmitting communication device,
A determining step of determining each of the receiving communication apparatuses that has received the data transmitted by the transmitting communication apparatus, and determining whether to perform the reply process based on the setting of the setting means of the receiving communication apparatus; ,
A data transfer method comprising: The communication system includes a communication management device having a storage unit that stores return permission / prohibition information that determines whether to execute the return process on each of the reception-side communication devices,
Notifying means of the communication management device further includes a notifying step of notifying each receiving communication device whether or not to perform the reply process in the receiving communication device, based on the reply availability information,
2. The data transfer method according to claim 1, wherein in the setting step, the setting unit performs setting based on the content notified by the notification step. Inquiring means of each of the receiving communication devices further includes an inquiry step of inquiring the communication management device whether or not to perform the reply process in the receiving communication devices,
3. The data transfer method according to claim 2, wherein, in the notifying step, the notifying unit performs the notification to a receiving communication device that has queried in the inquiring step. The reply permission / non-permission information classifies the plurality of receiving-side communication devices into a plurality of groups, and determines whether or not to cause each of the receiving-side communication devices to execute a reply process for each of the groups. Item 3. The data transfer method according to Item 2. 5. The data transfer method according to claim 4, wherein the reply permission / prohibition information classifies the plurality of receiving-side communication devices into the plurality of groups based on a priority order in which the reply process is executed. The reply permission / non-permission information classifies the plurality of receiving communication devices into a plurality of groups based on an attribute of each receiving communication device, and determines whether or not to allow each receiving communication device to execute a reply process for each group. Stipulated in
A group discriminating step in which a group discriminating unit of the communication management device discriminates to which group the receiving communication device belongs, based on the reply permission / prohibition information and the attribute of each of the receiving communication devices;
A recognition step in which a recognition unit of the communication management device recognizes whether or not to cause the receiving communication device to execute the reply process based on a determination result obtained by the group determination step.
Further comprising
3. The data transfer method according to claim 2, wherein in the notifying step, the notifying unit notifies a recognition result obtained in the recognition step. 3. The data transfer method according to claim 2, wherein the rewriting means of the communication management device further includes a rewriting step of rewriting the reply propriety information. The reply propriety information classifies the plurality of receiving communication devices into a plurality of groups, and determines a representative communication device that performs the reply process on behalf of the receiving communication devices belonging to the group for each group, 3. The data transfer method according to claim 2, wherein whether or not each of the representative communication devices executes a reply process is determined for each of the groups. 9. The communication control apparatus according to claim 8, further comprising a change step of changing the representative communication device of each group in the reply propriety information to another receiving communication device belonging to each group. Data transfer method described in 1. The data transfer method according to claim 2, wherein the communication management device is provided in the transmission-side communication device. In a communication system that performs data transfer via a communication network,
When receiving data via the communication network, a plurality of receiving communication devices capable of executing a reply process for returning, via the communication network, acknowledgment data for notifying that the data has been received When,
Including a communication management device that determines whether or not to execute the reply process in each of the receiving communication devices,
The communication management device,
Storage means for storing, in each of the receiving-side communication devices, reply permission / non-permission information that determines whether or not to execute the reply process;
Recognition means for recognizing whether or not to allow each of the receiving communication devices to execute the reply process based on the reply permission / prohibition information,
Notifying means for notifying each communication device of a recognition result by the recognizing means,
A communication system comprising: The communication device further includes a transmission-side communication device that transmits data to the reception-side communication device via the communication network.
The communication system according to claim 11, wherein the communication management device is provided in the transmission-side communication device. In a communication management device that manages a communication system capable of transferring data from a transmitting communication device to a plurality of receiving communication devices via a communication network,
When each of the receiving communication devices receives data via the communication network, execution of a reply process for returning, via the communication network, acknowledgment data for notifying that the data has been received is performed. Is possible,
A storage unit that stores reply permission / prohibition information that determines whether or not each of the receiving communication devices performs the reply process.
Recognition means for recognizing whether or not to allow each of the receiving communication devices to execute the reply process based on the reply permission / prohibition information,
Notifying means for notifying each communication device of a recognition result by the recognizing means,
A communication management device comprising: 14. The communication management device according to claim 13, wherein the communication management device is provided in the transmission-side communication device. A communication management program for causing a computer to function as each unit of the communication management device according to claim 13. A computer-readable recording medium on which the communication management program according to claim 15 is recorded.

Images