JP7060247B2 - Communication devices, communication systems, communication methods, and programs - Google Patents

Description

The present invention relates to communication devices, communication systems, communication methods, and programs.

A wireless bridge device for connecting a communication device having only a wired communication interface to a wireless network is used. When a communication frame (also simply called a frame) is transmitted from a base station (also called a master unit) to a wireless bridge device (also called a slave unit) by wireless communication, the frame is caused by radio noise or instability of radio wave propagation. May be lost, that is, lost.

In unicast communication on a wireless LAN (Local Area Network) of the IEEE802.11 standard, frame loss can be recovered to some extent by arrival confirmation and retransmission control by ACK.

On the other hand, content is distributed via a network including a wireless network in part. In such content distribution, content data is transmitted by broadcast or multicast from a server that is a source to one or more terminals via a network.

Patent Document 1 discloses a conversion device that converts a unicast communication packet into multicast and also converts a multicast communication packet into unicast.

Japanese Unexamined Patent Publication No. 2007-60197

As described above, in broadcasting or multicast content distribution via a network including a part of the wireless network, there is a problem that frame loss may occur in the part of the wireless network. When frame loss occurs, the content data does not reach the receiving terminal that receives the content, and there is a problem that the content is not properly played back on the receiving terminal.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a communication device or the like that suppresses frame loss in content distribution via a network including a part of a wireless network.

In order to solve the above problems, the communication device according to one aspect of the present invention is a communication device that is a master unit that wirelessly communicates with one or more slave units, and has a first interface for wired communication and the above-mentioned one or more. The second interface that wirelessly communicates with each of the slave units and the broadcast frame received by the first interface are converted into a unicast frame in a 4-address format and transmitted to each of the one or more slave units by the second interface. It is equipped with a conversion unit.

According to this, the master unit, which is a communication device, transmits data to the slave unit by using a unicast frame in the 4-address format of wireless communication, and distributes the data to the terminal located in front of the slave unit. do. Since a unicast frame is used in the wireless network part, frame loss can be suppressed, and since a 4-address format unicast frame is used, distribution to a terminal located in front of the slave unit can be realized. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network.

Further, the unicast frame transmitted to each of the one or more slave units has a MAC (Media Access Control) address of the slave unit in the RA (Receiver Address) field included in the unicast frame, and the unicast frame is described. The DA (Destination Address) field included in the cast frame may have a broadcast address.

According to this, the master unit, which is a communication device, appropriately uses the RA field and the DA field in the 4-address format unicast frame to more easily distribute the content via the network including a part of the wireless network. Frame loss can be suppressed in.

Further, when the second interface establishes a communication link with each of the one or more slave units, the second interface generates a list of MAC addresses of each of the one or more slave units, and the conversion unit performs the conversion. For each of the one or more slave units, the unicast frame in which the MAC address of the slave unit is set in the RA field may be generated and transmitted in sequence.

According to this, the master unit, which is a communication device, uses the list generated at the time of establishing the communication link for wireless communication with each slave unit, and sequentially assigns the MAC addresses of the slave units included in the list to RA. Set in the field to generate a 4-address format unicast frame. Therefore, no other processing is required to acquire the identifier of the slave unit. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network by using the data that can be generated when the communication link is established.

Further, the conversion unit may convert only the broadcast frame satisfying a predetermined condition from the broadcast frames received by the first interface into the unicast frame and transmit the frame.

According to this, the master unit, which is a communication device, can deliver not all of the received broadcast frames but only a specific part of the broadcast frames to the terminal via the slave unit. Therefore, it is possible to prevent unnecessary traffic from flowing to the network by preventing the slave unit from receiving unnecessary frames. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network while suppressing the flow of unnecessary traffic to the network.

Further, in order to solve the above problems, the communication device according to one aspect of the present invention is a communication device that is one of one or more slave units that wirelessly communicate with the master unit, and is one or more. The first interface for wired communication with each terminal, the second interface for wireless communication with the master unit, and the second interface are unicast frames in a four-address format, and (a) the unicast frame. When a unicast frame having the address of the communication device in the included RA field and (b) having a broadcast address in the DA field included in the unicast frame is received from the master unit, the received unicast frame. May be provided with a conversion unit that converts the above into a broadcast frame or does not convert the

According to this, the slave unit, which is a communication device, converts the 4-address format unicast frame transmitted from the master unit into a broadcast and transmits it to the terminal. Since a unicast frame is used in the wireless network part, frame loss can be suppressed, and since a 4-address format unicast frame is used, distribution to a terminal located in front of the slave unit can be realized. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network.

Further, the conversion unit may convert the received unicast frame into a broadcast frame and transmit it to the one or more terminals by the first interface.

According to this, the slave unit, which is a communication device, can return the 4-address format unicast frame received from the master unit to the broadcast before being converted into the unicast frame and transmit it to the terminal. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network.

Further, the conversion unit may transmit the received unicast frame to a predetermined terminal among the one or more terminals by the first interface.

According to this, the slave unit, which is a communication device, can transmit the 4-address format unicast frame received from the master unit only to a specific terminal, so that it is possible to transmit this data to a terminal that does not need to receive it. Be avoided. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network while suppressing the flow of unnecessary traffic to the network.

Further, even if the conversion unit transmits to the one or more terminals by the first interface only when the UDP (User Datagram Protocol) port number of the unicast frame received by the second interface satisfies a predetermined condition. good.

According to this, the slave unit, which is a communication device, can transmit only the data of a specific UDP port among the 4-address format unicast frames received from the master unit to the terminal, so that the data of this UDP port can be received. Avoid sending to terminals that don't need it. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network while suppressing the flow of unnecessary traffic to the network.

Further, the communication system according to one aspect of the present invention includes the above-mentioned communication device as the master unit and the above-mentioned communication device as the slave unit.

According to this, the communication system has the same effect as the above-mentioned communication device.

Further, the communication method according to one aspect of the present invention is a communication device which is a master unit that wirelessly communicates with one or more slave units, and wirelessly communicates with the first interface for wired communication and each of the one or more slave units. A communication method using a communication device including a second interface for communication, wherein the broadcast frame received by the first interface is converted into a unicast frame in a 4-address format, and the conversion step is converted. A transmission step of transmitting a unicast frame to each of the one or more slave units by the second interface is included.

According to this, the communication method has the same effect as the above-mentioned communication device.

Further, the communication method according to one aspect of the present invention is a communication device that is a slave unit of one or more slave units that wirelessly communicate with the master unit, and performs wired communication with each of the one or more terminals. A communication method using a communication device including one interface and a second interface for wireless communication with the master unit, wherein the second interface is a four-address format unicast frame, and (a) the unicast. A reception step of receiving the unicast frame having the address of the communication device in the RA field included in the frame and having a broadcast address in the DA field included in the unicast frame from the master unit, and the receiving step. When the unicast frame is received in, the received unicast frame is converted into a broadcast frame, or is transmitted to the one or more terminals by the first interface without being converted into a broadcast frame. And include.

According to this, the communication method has the same effect as the above-mentioned communication device.

Further, the program according to one aspect of the present invention is a program for causing a computer to execute the above communication method.

According to this, the program has the same effect as the above-mentioned communication device.

It should be noted that the present invention can be realized not only as a device, but also as a method using a processing means constituting the device as a step, as a program for causing a computer to execute those steps, or as a computer reading in which the program is recorded. It can also be realized as a possible recording medium such as a CD-ROM, or as information, data or a signal indicating the program. The programs, information, data and signals may be distributed via a communication network such as the Internet.

According to the present invention, a communication device or the like can suppress frame loss in content distribution via a network including a part of a wireless network.

FIG. 1 is an explanatory diagram showing a configuration of a communication system according to an embodiment. FIG. 2 is an explanatory diagram showing a functional configuration of the master unit according to the embodiment. FIG. 3 is an explanatory diagram showing a functional configuration of the slave unit according to the embodiment. FIG. 4 is an explanatory diagram showing an address field of a frame transmitted / received by the communication system according to the embodiment. FIG. 5 is an explanatory diagram showing an example of a slave unit list of the master unit according to the embodiment. FIG. 6 is a flow chart showing the processing of the master unit according to the embodiment. FIG. 7 is a flow chart showing the processing of the slave unit according to the embodiment. FIG. 8 is an explanatory diagram showing a first example of a rule possessed by the master unit according to the embodiment. FIG. 9 is an explanatory diagram showing a second example of the rule possessed by the master unit according to the embodiment. FIG. 10 is an explanatory diagram showing an example of a terminal list included in the handset according to the embodiment. FIG. 11 is an explanatory diagram showing an example of a terminal list included in the handset according to the embodiment. FIG. 12 is an explanatory diagram showing an example of a rule possessed by the handset according to the embodiment. FIG. 13 is an explanatory diagram showing a frame transfer path in the communication system according to the embodiment.

Hereinafter, embodiments will be specifically described with reference to the drawings.

Each of the embodiments described below shows a preferred specific example of the present invention. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps, the order of steps, and the like shown in the following embodiments are examples, and are not intended to limit the present invention. Further, among the components in the following embodiments, the components not described in the independent claims showing the highest concept of the present invention will be described as arbitrary components constituting the more preferable form. The same components may be designated by the same reference numerals and description thereof may be omitted.

(Embodiment)
In the present embodiment, a communication device that suppresses frame loss in content distribution via a network including a wireless network in part will be described.

FIG. 1 is an explanatory diagram showing a configuration of a communication system 1 according to the present embodiment.

As shown in FIG. 1, the communication system 1 includes a server 5, a master unit A1, slave units B1 and B2, and terminals T1, T2, T3, T4, T5, and T6. The server 5, the master unit A1, and the terminal T1 are connected to each other so as to be able to communicate with each other by the network N1. The master unit A1 and the slave units B1 and B2 are connected to each other so as to be able to communicate with each other by the network N2. The slave unit B1 and the terminals T2, T3 and T4 are connected to each other so as to be able to communicate with each other by the network N3. The slave unit B2 and the terminals T5 and T6 are connected to each other so as to be able to communicate with each other by the network N4.

The master unit A1 is a master unit among a master unit (generally referred to as a base station or an access point (AP)) and a slave unit (generally also referred to as a station (STA)) that communicate wirelessly with each other. Further, the slave unit B1 is a slave unit among a master unit and a slave unit that wirelessly communicate with each other, and is generally also referred to as a wireless bridge or a wireless bridge device. The slave unit B1 does not have a function of a master unit, that is, a base station (for example, a function of transmitting a beacon signal). The slave unit B2 is the same as the slave unit B1.

The case where the number of slave units is two will be described as an example, but the number of slave units may be any number as long as it is one or more.

The network N2 is a wireless communication network in which retransmission control is performed in the case of unicast transmission, and retransmission control is not performed in the case of broadcast or multicast transmission, and communication is performed according to a communication standard. An example of the communication standard of the network N2 is a wireless LAN (Local Area Network) standard of the IEEE802.11 series (IEEE802.11.a, b, g, n, ac, ax, etc.), and this case will be described as an example. However, it is not limited to this.

Further, the networks N1, N3 and N4 may be any communication standard, but a communication standard having less communication loss than the network N2 is assumed, and is, for example, a wired communication network. Examples of communication standards for networks N1, N3 and N4 are wired LAN standards such as Ethernet® or IEEE 802.3.

The server 5 is a distribution server device that distributes data to terminals T1 to T6. The server 5 holds content data related to content such as audio or video, divides the content data into relatively small data units (for example, about 1000 bytes) and includes the frame 6 in the frame 6, and the frame 6 is included in the network N1. Broadcast to. The transmitted frame 6 is received by the master unit A1 and the terminal T1.

The master unit A1 receives the frame 6 broadcasted by the server 5 via the network N1, and transmits the received frame 6 to the slave units B1 and B2 via the network N2 as a frame 7. The master unit A1 converts the received frame 6 into unicast, and sequentially transmits it to the slave units B1 and B2 as frame 7 by unicast. The transmitted frame 7 is received by the slave units B1 and B2.

The slave unit B1 receives the frame 7 transmitted by the master unit A1 in unicast, and in principle, converts the received frame 7 into a broadcast and transmits it to the terminals T2, T3, and T4 as a frame 8. As will be described later, as an exception, the handset B1 may unicast the received frame 7 to some or all of the terminals T2, T3 and T4 without converting it into a broadcast. be.

The slave unit B2 receives the frame 7 transmitted by the master unit A1 in unicast, and in principle, converts the received frame 7 into a broadcast and transmits it to the terminals T5 and T6 as a frame 9. The slave unit B2 has the same function as the slave unit B1 and operates independently of the slave unit B1. The exceptional operation of the slave unit B1 is the same for the slave unit B2.

The terminals T1 to T6 are terminal devices that reconstruct content data from data units included in received frames and reproduce audio or moving image content. The terminal T1 receives the frame 6 from the server 5 via the network N1. The terminals T2, T3 and T4 receive the frame 8 from the slave unit B1 via the network N3. The terminals T5 and T6 receive the frame 9 from the slave unit B2 via the network N4.

Hereinafter, the master unit A1 and the slave unit B1 and the like will be described in detail.

FIG. 2 is an explanatory diagram showing a functional configuration of the master unit A1 according to the present embodiment. The master unit A1 is a communication device that is a base station that wirelessly communicates with one or more slave units.

As shown in FIG. 2, the master unit A1 includes a communication IF 11, a wireless IF 12, and a conversion unit 13. The communication IF 11 corresponds to the first interface included in the master unit A1, and the wireless IF 12 corresponds to the second interface included in the master unit A1.

The communication IF 11 is a communication interface device that is communicably connected to the server 5, and performs communication compliant with, for example, Ethernet. When the communication IF 11 receives the frame 6 which is a broadcast frame from the server 5, the communication IF 11 provides the received frame 6 to the conversion unit 13.

The wireless IF 12 is a communication interface device that is connected to each of the slave units B1 and B2 so as to be capable of wireless communication, and performs communication conforming to, for example, the IEEE802.11 series wireless LAN standard. The wireless IF 12 functions as an interface of a master unit for wireless communication with the slave units B1 and B2, and for example, periodically transmits a beacon.

The wireless IF 12 establishes a wireless communication link with each of the slave units B1 and B2, and provides the conversion unit 13 with identification information (for example, a MAC address) of the device of the other party for which the wireless communication link is established. The wireless IF 12 transmits the frame 7 to the slave units B1 and B2 under the control of the conversion unit 13.

The conversion unit 13 is a processing unit that converts the frame 6 received by the communication IF 11. The conversion unit 13 acquires a frame 6 which is a broadcast frame received by the communication IF 11, converts the frame 6 into a unicast frame in a 4-address format, and transmits the frame 6 to each of the slave units B1 and B2 by the wireless IF 12. The conversion unit 13 can be realized by the processor executing a predetermined program using the memory.

Specifically, the conversion unit 13 duplicates the 4-address format unicast frame converted from the broadcast frame so that the number of slave units B1 and B2 is (that is, two), and RA (RA) of each unicast frame. The above conversion is performed by setting the MAC address of the destination slave unit in the Receiver Address) field. Specifically, the conversion unit 13 sets the MAC address of the slave unit B1 in the RA field of the 4-address format unicast frame transmitted to the slave unit B1, and transmits the 4-address format unicast to the slave unit B2. Set the MAC address of the slave unit B2 in the RA field of the cast frame. The 4-address format unicast frame will be described in detail later.

Further, the conversion unit 13 acquires the identifier of the other party's device for which the wireless communication link is established from the wireless IF 12, and holds the identifier as the list 16. The identifier may be any information as long as it can uniquely identify the device of the other party that has established the wireless communication link. Here, an example in which the MAC address is used as the identifier will be described. Not limited. The conversion unit 13 sets the MAC address in the RA field of the generated unicast frame for each MAC address shown in Listing 16.

The conversion unit 13 has a rule 17, and can control the transmission of the unicast frame according to the rule 17. Rule 17 and control of unicast transmission will be described later.

FIG. 3 is an explanatory diagram showing a functional configuration of the slave unit B1 according to the present embodiment. The slave unit B1 is a communication device that is one of one or more wireless bridge devices that wirelessly communicate with the master unit A1. The slave unit B2 also has the same configuration as the slave unit B1.

As shown in FIG. 3, the slave unit B1 includes a communication IF 21, a wireless IF 22, and a conversion unit 23. The communication IF 21 corresponds to the first interface included in the slave unit B1, and the wireless IF 22 corresponds to the second interface included in the slave unit B1.

The communication IF 21 is a communication interface device communicably connected to the terminals T2, T3 and T4, and performs communication compliant with, for example, Ethernet. The communication IF 21 transmits the frame 8 to the terminals T2, T3 and T4 under the control of the conversion unit 23.

The wireless IF 22 is a communication interface device that is connected to the master unit A1 so as to be capable of wireless communication, and performs communication conforming to, for example, the IEEE802.11 series wireless LAN standard. The wireless IF 22 establishes a wireless communication link with the master unit A1. When the wireless IF 22 receives the frame 7 which is a unicast frame in the 4-address format from the master unit A1, the received frame 7 is provided to the conversion unit 23.

The conversion unit 23 is a processing unit that converts the frame 7 received by the wireless IF 22. The conversion unit 23 can be realized by the processor executing a predetermined program using the memory.

Here, the frame 7 is a unicast frame in a 4-address format, and the address of the own device (that is, the slave unit B1) is set in the RA field included in the unicast frame. In addition, a broadcast address is set in the DA field included in the unicast frame.

When the frame 7 is received by the wireless IF 22, the conversion unit 23 converts the received unicast frame into a broadcast frame or does not convert the received unicast frame into a broadcast frame, but the terminal T2, as a frame 8 by the communication IF 21, Send to T3 and T4. In principle, the conversion unit 23 converts the frame 7 received by the wireless IF 22 into a broadcast frame and transmits it as the frame 8 by the communication IF 21. Further, when a predetermined condition is satisfied, the conversion unit 23 does not convert the frame 7 received by the wireless IF 22 into a broadcast frame, but transmits it as a frame 8 by the communication IF 21 as it is unicast. Here, whether or not to convert to a broadcast frame and transmit or not can be controlled by, for example, whether or not the conversion unit 23 possesses the list 25. The contents of Listing 25 and the above controls will be described in detail later.

Further, the conversion unit 23 possesses the rule 26 and can control the transmission of the unicast frame according to the rule 26. Rule 26 and control of unicast transmission will be described later.

FIG. 4 is an explanatory diagram showing an address field of a frame transmitted / received by the communication system 1 according to the present embodiment. Specifically, the address field of frame 6 is shown in (a) of FIG. 4, the address field of frame 7 is shown in (b) of FIG. 4, and the address field of frame 7 is shown in (c) of FIG. Address field is shown.

The frame 6 is a frame transmitted by the server 5 and received by the master unit A1, and has a frame format of an Ethernet frame.

As shown in FIG. 4A, the address field of frame 6 includes a DA (Destination Address) field and an SA (Source Address) field.

The DA field is a field indicating the destination address of frame 6, and includes the broadcast address. The broadcast address is "ff: ff: ff: ff: ff: ff", and the multicast address is an address starting with "01:00: 5E".

The SA field is a field indicating the address of the source of the frame 6, and includes the MAC address of the server 5.

The frame 7 is a frame transmitted by the master unit A1 and received by the slave unit B1, and has a frame format of a 4-address format of the IEEE802.11 series wireless LAN. This frame format is the same as that generally used for communication between base stations in WDS (Wireless Distribution System).

As shown in FIG. 4B, the address field of frame 7 includes an RA field, a TA (Transmitter Address) field, a DA field, and an SA field.

The RA field is a field indicating the address of the next transfer destination of the frame 7, and includes the MAC address of the slave unit B1.

The TA field is a field indicating the address of the transfer source of the frame 7, and includes the MAC address of the master unit A1.

The DA field and the SA field are the same as the fields having the same name in the frame 6.

The frame 8 is a frame transmitted by the slave unit B1 and received by the terminal T2, and has a frame format of an Ethernet frame.

As shown in FIG. 4 (c), the DA field and the SA field are the same as the fields having the same name in the frame 6.

The process until the master unit A1 receives the frame 6 and transmits the frame 7 is as follows.

That is, when the master unit A1 receives the frame 6, the conversion unit 13 determines whether or not the DA field of the received frame 6 is a broadcast address. When it is determined that the address is a broadcast address, the conversion unit 13 maintains the DA field and the SA field of the frame 6 and adds the RA field and the TA field to generate a 4-address format unicast frame. In other words, the frame 7 has the MAC address of the slave unit in the RA field and the broadcast address in the DA field for each of the slave units B1 and B2. In this way, the conversion unit 13 generates the frame 7.

Further, the process until the slave unit B1 receives the frame 7 and transmits the frame 8 is as follows.

That is, when the slave unit B1 receives the frame 7, the conversion unit 23 determines whether or not the RA field of the frame 7 is the address of the own device (that is, the slave unit B1). When it is determined that the address is the address of the own device, the conversion unit 23 erases the RA field and the TA field of the frame 7 and maintains the DA field and the SA field. In this way, the conversion unit 23 generates the frame 8.

If a frame format other than the 4-address format, specifically, a frame format containing only three addresses used for communication between a base station and a terminal of general wireless communication is used, the slave unit B1 is a frame 7. After receiving the message, the specified MAC address must be set in the DA field of the frame to be transmitted to the terminal. Therefore, the slave unit B1 cannot restore the MAC address itself set in the DA field of the frame 6 transmitted by the server 5.

Since the communication system 1 uses the frame format of the 4-address format for the frame 7, the slave unit B1 simply maintains the DA field of the received frame 7 without editing, and displays the DA field of the frame 6 transmitted by the server 5. It has the advantage that it can be used and does not require any other processing for setting the DA field. In particular, when the DA field of frame 6 transmitted by the server 5 is a multicast address, there is an advantage that the multicast address is set as it is in the DA field of frame 8 transmitted by the slave unit B1.

FIG. 5 is an explanatory diagram showing an example of list 16 included in the master unit A1 according to the present embodiment. Listing 16 shows a list of slave units of the other party that have established a communication link with the master unit A1.

Prior to wireless communication with the slave unit, the master unit A1 has an attribution request (Association Request), an attribution response (Association Response), an authentication request (Authentication Request), and an authentication response (Authentication Response) with the slave unit. Through the transmission and reception of each frame of Authentication Response), a communication link for wireless communication with the slave unit is established. When the communication link is established in this way, the wireless IF 12 provides the MAC address to the conversion unit 13 as an identifier of the slave unit to which the communication link is established. The conversion unit 13 generates a list 16 including the MAC address of the provided slave unit.

The list 16 shown in FIG. 5 is a list when the master unit A1 establishes a communication link with each of the slave units B1 and B2, and includes the MAC addresses of the slave units B1 and B2.

When the master unit A1 receives a broadcast frame by the communication IF 11 while having the list 16, the conversion unit 13 sequentially selects the addresses included in the list 16, that is, the MAC addresses of the slave units B1 and B2. A unicast frame set in the RA field is generated and transmitted by wireless IF12. In this way, the master unit A1 sequentially transmits the broadcast frame received from the server 5 to each of the slave units B1 and B2 as a unicast frame.

FIG. 6 is a flow chart showing the processing of the master unit A1 according to the present embodiment.

In step S101, the conversion unit 13 determines whether or not the broadcast frame has been received by the communication IF 11. If it is determined that the broadcast frame has been received (Yes in step S101), the process proceeds to step S102, and if not (No in step S101), step S101 is executed again. That is, the conversion unit 13 waits in step S101 until the broadcast frame is received by the communication IF 11.

In step S102, the conversion unit 13 executes the start processing of the loop A. In the loop A, the processes from step S103 to step S104 are executed, paying attention to each slave unit to which the master unit A1 has established a communication link.

In step S103 (corresponding to the conversion step), the conversion unit 13 converts the broadcast frame received in step S101 into a 4-address format unicast frame. This conversion corresponds to the conversion from (a) to (b) in FIG. In the RA field of the unicast frame generated by the conversion, the MAC address of the slave unit of interest in the loop A process is set.

In step S104 (corresponding to the transmission step), the conversion unit 13 transmits the unicast frame generated by the conversion in step S103 by the wireless IF 12.

In step S105, the conversion unit 13 executes the end processing of the loop A. Specifically, it is determined whether or not the execution of the processes from step S102 to step S104 is completed for all the slave units to which the master unit A1 has established the communication link. If the execution of the above processing is not completed for all the slave units, the process returns to the first processing (step S103) in the loop A to perform the processing for the next slave unit. If not, the loop A And ends the series of processes shown in this flow chart.

Through the above series of processes, the master unit A1 sequentially transmits the broadcast frame received from the server 5 to the slave units B1 and B2 by unicast.

FIG. 7 is a flow chart showing the processing of the slave unit B1 according to the present embodiment.

In step S201 (corresponding to the reception step), the conversion unit 23 determines whether or not the unicast frame in the 4-address format has been received by the wireless IF 22. If it is determined that the unicast frame has been received (Yes in step S201), the process proceeds to step S202, and if not (No in step S201), step S201 is executed again. That is, the conversion unit 23 waits in step S201 until the unicast frame is received by the wireless IF 22.

In step S202, the conversion unit 23 converts the unicast frame received in step S201 into a broadcast frame. This conversion corresponds to the conversion from (b) to (c) in FIG.

In step S203, the conversion unit 23 transmits the broadcast generated by the conversion in step S202 by the communication IF 21.

Note that steps S202 and S203 correspond to conversion steps.

Through the above series of processes, the slave unit B1 converts the 4-address format unicast received from the master unit A1 into a broadcast and transmits it to the terminals T2, T3, and T4.

Hereinafter, the operation when the rule 17 of the master unit A1 and the list 25 and the rule 26 of the slave unit B1 are present will be described in order.

(1) Rule 17 of the master unit A1 A control of transmission of a unicast frame using the rule 17 by the conversion unit 13 of the master unit A1 will be described.

The conversion unit 13 can control that, among the broadcast frames received by the communication IF 11, only the broadcast frames satisfying a predetermined condition are converted into unicast frames and transmitted. Rule 17 is used to specify predetermined conditions.

As an example of such control, the conversion unit 13 controls whether or not to convert to a unicast frame and transmit it in units of UDP port numbers. In this case, rule 17 describes the UDP port number of the broadcast frame to be converted into a unicast frame. Among the broadcast frames received by the communication IF 11, the conversion unit 13 converts the frame having the UDP port number described in the rule 17 into a unicast frame.

FIG. 8 is an explanatory diagram showing a first example of the rule 17 included in the master unit A1. In the rule 17 shown in FIG. 8, the UDP port number of the broadcast frame to be converted into the unicast frame by the conversion unit 13 is shown.

Specifically, rule 17 in FIG. 8 indicates 12345 and 23456 as UDP port numbers.

At this time, the conversion unit 13 converts the broadcast frame having the UDP port number 12345 or 23456 into a unicast frame and transmits it to the slave units B1 and B2, and controls not to transmit other broadcast frames.

This makes it possible to prevent broadcast frames that are not content data from being broadcast to the entire communication system 1.

The conversion unit 23 can also perform more detailed control. For example, in the above control, the conversion unit 23 can limit the slave unit that is the destination to be converted into a unicast frame and transmitted. This rule is referred to as rule 17A.

In this case, rule 17A describes the UDP port number of the broadcast frame to be converted into the unicast frame, and the slave unit to which the unicast frame having the UDP port number is transmitted. Among the broadcast frames received by the communication IF 11, the conversion unit 13 converts the frame having the UDP port number described in rule 17A into a unicast frame, and the unicast frame generated by the conversion is associated with the rule 17A. Send to the handset and do not send to other handset. In this way, the conversion unit 13 limits the transmission destination of the unicast frame to the slave unit associated with the rule 17A.

FIG. 9 is an explanatory diagram showing rule 17A, which is a second example of rule 17 possessed by the master unit A1. In rule 17A shown in FIG. 9, the UDP port number of the broadcast frame to be converted into the unicast frame by the conversion unit 13 and the slave unit to which the frame having the UDP port number is the destination are shown.

Specifically, rule 17A of FIG. 9 indicates 12345 and 23456 as UDP port numbers.

At this time, the conversion unit 13 converts the broadcast frame having the UDP port number 12345 into a unicast frame and transmits it to the slave unit B1 but does not transmit it to the slave unit B2. Further, the conversion unit 13 converts the broadcast frame having the UDP port number 23456 into a unicast frame and transmits it to the slave units B1 and B2. Then, the conversion unit 13 controls so that the broadcast frame whose UDP port number is other than the above is not transmitted to any slave unit.

As a result, it is possible to prevent a frame that does not need to be received by the slave unit or the terminal from being broadcast to the entire communication system 1.

(2) List 25 of the handset B1 The control of the transmission of the unicast frame using the list 25 by the conversion unit 23 of the handset B1 will be described.

The conversion unit 23 can control that among the unicast frames received by the wireless IF 22, only the unicast frames satisfying a predetermined condition are transmitted as unicast frames without being converted into broadcast frames. Listing 25 is used to define predetermined conditions.

As an example of such control, the conversion unit 23 controls, for each terminal, whether to convert to a broadcast frame or to transmit as a unicast frame without converting to a broadcast frame. In this case, the identifier (for example, the MAC address of the terminal) of the terminal to be transmitted as the unicast frame is described in the list 25. When the conversion unit 23 has the list 25, the conversion unit 23 transmits the unicast frame received by the wireless IF 22 to the terminal listed in the list 25 as the unicast frame as it is. At this time, if a plurality of terminals are listed in the list 25, the unicast frame is sequentially transmitted to the plurality of terminals. The unicast frame received by the wireless IF 22 is not transmitted to the terminal not listed in Listing 25.

FIG. 10 is an explanatory diagram showing an example of the list 25 included in the slave unit B1. In the list 25 shown in FIG. 10, the identifier of the terminal to which the conversion unit 23 transmits the unicast frame is shown.

Specifically, the terminal T2 is shown in Listing 25 of FIG.

At this time, the conversion unit 23 converts the 4-address format unicast frame received from the master unit A1 into an Ethernet unicast frame and transmits it to the terminal T2, and sends it to the other terminals (that is, terminals T3 and T4). Control not to send.

(3) Rule 26 of the slave unit B1 The control of the transmission of the unicast frame using the rule 26 by the conversion unit 23 of the slave unit B1 will be described.

The conversion unit 23 can control that only the unicast frames that satisfy a predetermined condition are transmitted to the terminal among the unicast frames received by the wireless IF 22. Rule 26 is used to specify predetermined conditions.

As an example of such control, the conversion unit 23 controls whether or not to transmit to the terminal in units of UDP port numbers. In this case, Rule 26 describes the UDP port number to be transmitted to the terminal. Among the unicast frames received by the wireless IF 22, the conversion unit 23 transmits the frame having the UDP port number described in the rule 26 to the terminal.

FIG. 11 is an explanatory diagram showing a first example of rule 26 included in the slave unit B1 according to the present embodiment.

In rule 26 shown in FIG. 11, the UDP port number of the broadcast frame transmitted by the conversion unit 23 is shown.

Specifically, rule 26 in FIG. 11 indicates a UDP port number, 12345.

At this time, the conversion unit 23 converts the 4-address format unicast frame received from the master unit A1 whose UDP port number is 12345 into an Ethernet broadcast and transmits it to the terminals T2, T3, and T4. ..

The conversion unit 13 can also perform more detailed control. For example, in the above control, the conversion unit 13 can specify a slave unit to be transmitted to the UDP port number to which the unicast frame is transmitted. In this case, rule 26 describes a UDP port number to be converted into a unicast frame and a terminal to which the unicast frame having the UDP port number is transmitted. Of the unicast frames received by the wireless IF 22, the conversion unit 23 transmits the unicast having the UDP port number described in the rule 26 only to the slave unit associated with the rule 26.

FIG. 12 is an explanatory diagram showing rule 26A, which is a second example of rule 26 included in the slave unit B1 according to the present embodiment.

In rule 26A shown in FIG. 12, the UDP port number of the broadcast frame transmitted by the conversion unit 23 and the identifier of the terminal to be transmitted by converting the broadcast frame having the UDP port number into a unicast frame are shown. ing.

Specifically, in rule 26A of FIG. 12, the UDP port number 12345 and the terminal T2 are shown in association with each other.

At this time, the conversion unit 23 converts the 4-address format unicast frame received from the master unit A1 having a UDP port number of 12345 into an Ethernet unicast frame and transmits it to the terminal T2. It is controlled not to transmit to terminals other than (that is, terminals T3 and T4).

This makes it possible to prevent broadcast frames that are not content data from being transmitted to unnecessary terminals.

The frame transfer path in the case of FIG. 12 will be described.

FIG. 13 is an explanatory diagram showing a frame transfer path in the communication system 1 according to the embodiment. The transfer route shown in FIG. 13 is a transfer route when the slave unit B1 has the list 25 shown in FIG. 10 or the rule 26A shown in FIG.

For example, among the terminals T2 to T6, it is assumed that the terminals T2, T5 and T6 have a display screen and the terminals T3 and T4 do not have a display screen. In this case, when the server 5 transmits the content data related to the content including the image in the broadcast frame, it is not necessary for the terminals T3 and T4 to receive the data.

In this case, if the slave unit B1 has the list 25 shown in FIG. 10 or the rule 26A shown in FIG. 12, it is possible to prevent the data from being delivered to the terminals T3 and T4. At this time, if the list 25 or the rule 26A is not set in the slave unit B2, the slave unit B2 converts the received 4-address unicast frame into a broadcast and transmits it to the terminals T5 and T6.

In the wireless network between the master unit A1 and the slave units B1 and B2, the number of frames transmitted and the band occupancy time of wireless communication between the case of using unicast and the case of using broadcast are described below. explain.

The number of frames transmitted is smaller when broadcast is used. This is because if broadcast is used, both the slave units B1 and B2 can receive the frame transmitted by the master unit A1. On the other hand, if unicast is used, the master unit A1 needs to transmit two frames, a frame destined for the slave unit B1 and a frame destined for the slave unit B2.

On the other hand, the band occupancy time of wireless communication may be shorter by using unicast. For broadcast, in a normal communication standard, the lowest transmission rate in the communication standard is used. For example, 6 Mbps is used for communication in the 5 GHz band, and 1 Mbps is used for communication in the 2.4 GHz band. On the other hand, for unicast transmission, transmission at a high transmission rate suitable for each slave unit is possible. For example, 54 Mbps can be used for IEEE802.11 g, and 300 Mbps can be used for IEEE802.11n.

Therefore, when unicast is used, the bandwidth occupancy time can be suppressed to be shorter than when broadcast is used, in other words, there is an advantage that more data can be transmitted in a predetermined period.

In the present embodiment, the communication system 1 includes a server 5, a master unit A1, slave units B1 and B2, and terminals T1 to T6, but the communication system 1 has a master unit A1. It may be provided with slave units B1 and B2.

As described above, in the communication device according to the present embodiment, the master unit, which is a communication device, transmits data to the slave unit by using a unicast frame in a 4-address format of wireless communication, and the slave unit thereof. Deliver to the terminal located ahead of. Since a unicast frame is used in the wireless network part, frame loss can be suppressed, and since a 4-address format unicast frame is used, distribution to a terminal located in front of the slave unit can be realized. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network.

In addition, the master unit, which is a communication device, appropriately utilizes the RA field and DA field in the 4-address format unicast frame to more easily frame loss in content distribution via a network including a part of the wireless network. Can be suppressed.

In addition, the master unit, which is a communication device, uses the list generated when establishing the communication link for wireless communication with each slave unit, and sequentially sets the MAC addresses of the slave units included in the list in the RA field. Since the unicast frame in the 4-address format is generated, no other processing is required to acquire the identifier of the slave unit. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network by using the data that can be generated when the communication link is established.

Further, the master unit, which is a communication device, can deliver not all of the received broadcast frames but only a specific part of the broadcast frames to the terminal via the slave unit. Therefore, it is possible to suppress the flow of unnecessary traffic to the network, such as preventing the slave unit from receiving unnecessary frames. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network while suppressing the flow of unnecessary traffic to the network.

Further, the slave unit, which is a communication device, converts the 4-address format unicast frame transmitted from the master unit into a broadcast and transmits it to the terminal. Since a unicast frame is used in the wireless network part, frame loss can be suppressed, and since a 4-address format unicast frame is used, distribution to a terminal located in front of the slave unit can be realized. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network.

In addition, the slave unit, which is a communication device, converts the 4-address format unicast frame received from the master unit into a broadcast, which is the form before being converted to the unicast frame, and then returns it to the terminal. Can be sent. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network.

Further, since the slave unit, which is a communication device, can transmit the 4-address format unicast frame received from the master unit only to a specific terminal, it is avoided to transmit this data to a terminal that does not need to receive it. .. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network while suppressing the flow of unnecessary traffic to the network.

Further, the slave unit, which is a communication device, can transmit only the data of a specific UDP port among the 4-address format unicast frames received from the master unit to the terminal, and therefore does not need to receive the data of this UDP port. Avoiding sending to the terminal. Therefore, the communication device can suppress frame loss in content distribution via a network including a part of the wireless network while suppressing the flow of unnecessary traffic to the network.

It should be noted that the present invention can be realized not only as a device, but also as a method using a processing means constituting the device as a step, as a program for causing a computer to execute those steps, or as a computer reading in which the program is recorded. It can also be realized as a possible recording medium such as a CD-ROM, or as information, data or a signal indicating the program. The programs, information, data and signals may be distributed via a communication network such as the Internet.

Although the communication device and the like of the present invention have been described above based on the embodiment, the present invention is not limited to this embodiment. As long as the gist of the present invention is not deviated, various modifications that can be conceived by those skilled in the art are applied to the present embodiment, and a form constructed by combining components in different embodiments is also included in the scope of the present invention. ..

The present invention can be used as a base station and a wireless bridge for wireless communication.

1 Communication system 5 Server 6, 7, 8, 9 Frame 11, 21 Communication IF
12, 22 Wireless IF
13, 23 Conversion unit 16, 25 List 17, 17A, 26, 26A Rule A1 Master unit B1, B2 Slave unit T1, T2, T3, T4, T5, T6 Terminal N1, N2, N3, N4 network

Claims (11)

A communication device that is a master unit that wirelessly communicates with one or more slave units.
The first interface for wired communication and
A second interface that wirelessly communicates with each of the above-mentioned one or more slave units,
It is provided with a conversion unit that converts a broadcast frame received by the first interface into a unicast frame in a four-address format and transmits the broadcast frame to each of the one or more slave units by the second interface .
The conversion unit
Of the broadcast frames received by the first interface, only the broadcast frames satisfying a predetermined condition are converted into the unicast frames and transmitted.
The predetermined condition includes a condition indicating the UDP port number of the broadcast frame to be converted into the unicast frame.
Communication device. The unicast frame transmitted to each of the one or more slave units is
The RA (Receiver Addless) field included in the unicast frame has the MAC (Media Access Control) address of the slave unit.
The communication device according to claim 1, which has a broadcast address in a DA (Destination Address) field included in the unicast frame. When the second interface establishes a communication link with each of the one or more slave units, the second interface generates a list of MAC addresses of each of the one or more slave units.
The conversion unit
The communication device according to claim 2, wherein the unicast frame in which the MAC address of the slave unit is set in the RA field is sequentially generated and transmitted for each of the one or more slave units by the conversion. A communication device that is a slave unit of one or more slave units that wirelessly communicate with the master unit.
The first interface for wired communication with each of one or more terminals,
The second interface that wirelessly communicates with the master unit,
The second interface is a 4-address format unicast frame, (a) having the address of the communication device in the RA field included in the unicast frame, and (b) DA included in the unicast frame. When a unicast frame having a broadcast address in the field is received from the master unit, a conversion unit that converts the received unicast frame into a broadcast frame and transmits the received unicast frame to the one or more terminals by the first interface. A communication device to be equipped. A communication device that is a slave unit of one or more slave units that wirelessly communicate with the master unit.
The first interface for wired communication with each of one or more terminals,
The second interface that wirelessly communicates with the master unit,
The second interface is a 4-address format unicast frame, (a) having the address of the communication device in the RA field included in the unicast frame, and (b) DA included in the unicast frame. When a unicast frame having a broadcast address in the field is received from the master unit, the received unicast frame is converted into a broadcast frame or is not converted into a broadcast frame. Equipped with a conversion unit that sends to the above terminals
The conversion unit
The received unicast frame is transmitted to a predetermined terminal among the one or more terminals by the first interface.
Communication device. A communication device that is a slave unit of one or more slave units that wirelessly communicate with the master unit.
The first interface for wired communication with each of one or more terminals,
The second interface that wirelessly communicates with the master unit,
The second interface is a 4-address format unicast frame, (a) having the address of the communication device in the RA field included in the unicast frame, and (b) DA included in the unicast frame. When a unicast frame having a broadcast address in the field is received from the master unit, the received unicast frame is converted into a broadcast frame or is not converted into a broadcast frame. Equipped with a conversion unit that sends to the above terminals
The conversion unit
UDP (User) of the unicast frame received by the second interface.
Datagram Protocol) Transmission to one or more terminals by the first interface only when the port number satisfies a predetermined condition.
Communication device. The communication device according to any one of claims 1 to 3 is provided as the master unit.
A communication system including the communication device according to any one of claims 4 to 6 as the slave unit. Communication by a communication device that is a master unit that wirelessly communicates with one or more slave units and includes a first interface for wired communication and a second interface for wireless communication with each of the one or more slave units. It ’s a method,
A conversion step of converting a broadcast frame received by the first interface into a unicast frame in a 4-address format, and a conversion step.
A transmission step of transmitting the unicast frame converted in the conversion step to each of the one or more slave units by the second interface is included.
In the conversion step,
Of the broadcast frames received by the first interface, only the broadcast frame satisfying a predetermined condition is converted into the unicast frame.
The predetermined condition includes a condition indicating the UDP port number of the broadcast frame to be converted into the unicast frame.
Communication method. A communication device that is a slave unit of one or more slave units that wirelessly communicate with a master unit, and has a first interface that performs wired communication with each of the one or more terminals, and a first interface that wirelessly communicates with the master unit. It is a communication method using a communication device equipped with two interfaces.
The second interface is a 4-address format unicast frame, (a) having the address of the communication device in the RA field included in the unicast frame, and (b) DA included in the unicast frame. A reception step of receiving a unicast frame having a broadcast address in the field from the master unit, and
A communication method including a conversion step including, when the unicast frame is received in the reception step, the received unicast frame is converted into a broadcast frame and transmitted to the one or more terminals by the first interface. A program for causing a computer to execute the communication method according to claim 8 . A program for causing a computer to execute the communication method according to claim 9 .

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