JP2008288875A - Client terminal, multicast communication control method, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize efficient multicast distribution by preventing useless multicast packet from flowing into a user house when using multicast distribution in a bidirectional CATV network. <P>SOLUTION: A client terminal connected to a multicast server through a router registers a multicast address in a managing part 26 for managing multicast addresses when receiving a participation request for the multicast address from a subordinate user terminal, eliminates the registered multicast address when receiving a withdrawal request for the multicast address from the user terminal and discards multicast packets other than multicast packets for the registered multicast without transferring the multicast packets to a communication I/F 28 from a coaxial I/F 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a client terminal, a multicast communication control method, a program, and a recording medium that support multicast distribution.

  In recent years, large-capacity contents have been distributed due to the infrastructure of communication systems. In particular, the distribution of video content by multicast is attracting attention. However, multicast distribution is efficient in the upper-level packet routing (route control) of the system, and wasteful multicast packets are not transferred to destinations other than the desired destination. There is a problem that a useless multicast packet flows into a user's home that is not desired in the same manner as a broadcast and places a load on the communication infrastructure in the home.

  For example, the following multicast communication methods are known for this problem.

  That is, in a bidirectional CATV network, when a terminal starts to receive a multicast packet, it transmits an IGMP (Internet Group Management Protocol) Membership Report Message to request the subscriber station to distribute data. The subscriber station starts the distribution of the required multicast packet dynamically by transferring the report message to the center station and then obtaining the group address information of the report message.

  The subscriber station periodically transmits an IGMP Membership Query Message to a terminal under its control to monitor whether there is a multicast packet that is no longer required for distribution, and there is no response from the terminal for a certain period of time or a group. When there is a withdrawal response from the mobile terminal and there is no other terminal that requests multicast packet delivery addressed to the same group, the delivery of packets that are no longer necessary is dynamically stopped.

In this way, when a center station or a subscriber station operates as a bridge device in a bidirectional CATV network, a subordinate terminal distributes without implementing a layer packet routing function or a routing information exchange function. There is a method of filtering and transferring only multicast packets addressed to a desired group address (see Patent Document 1).
JP 2000-125277 A (Japanese Patent Application No. 10-297370)

  However, in the conventional communication method described above, the multicast address filter is not immediately deleted even after the terminal leaves the multicast group. Therefore, when another terminal is watching the same program, an inquiry by the IGMP Membership Query Message is made. Until then, there is a problem that a useless multicast packet flows to a user's house that should have left.

  An object of the present invention is to provide a client terminal that does not transfer a useless multicast packet and does not put a load on a user's network in consideration of the problems of the conventional multicast communication method.

A first aspect of the present invention is a client terminal to which a user terminal can be communicated with a multicast-compatible router,
A first interface capable of communicating with the router;
A first transmission / reception processing unit connected to the first interface for processing data communication;
A transfer control unit connected to the first transmission / reception processing unit to control data transfer;
A multicast address management unit connected to the transfer control unit and managing a multicast address in which the user terminal participates;
A second transmission / reception processing unit connected to the transfer control unit for processing data communication;
A second interface connected to the second transmission / reception processing unit and capable of communicating with the user terminal,
The transfer control unit manages the multicast address management unit according to information including a join request or withdrawal request regarding a multicast address received through the second interface, and uses the multicast address management unit to transmit data to be received A client terminal that performs filter processing.

  The second aspect of the present invention is the client terminal according to the first aspect of the present invention, wherein the transfer control unit includes a filter processing unit that discards the received data when the received data is multicast packet data not registered in the multicast address management unit. It is.

  According to a third aspect of the present invention, when the transfer control unit receives a request for participation in the multicast address transmitted by the user terminal, the multicast address is registered in the multicast address management unit, and the user terminal participates. The client terminal according to the first aspect of the present invention includes an IGMP management unit that deletes a corresponding multicast address registered in the multicast address management unit when a withdrawal request for the multicast address is received.

  A fourth aspect of the present invention is the client terminal according to the first aspect of the present invention, further comprising a timer management unit that manages a timer for deleting a multicast address to which the user terminal of the multicast address management unit belongs.

  In a fifth aspect of the present invention, when the transfer control unit receives a request for participation in the multicast address transmitted by the user terminal, the multicast address is registered in the multicast address management unit, and the user terminal participates. When a withdrawal request for the multicast address is received, the timer for deleting the corresponding multicast address registered in the multicast address management unit is started, and registered in the multicast address management unit when the timer expires It is a client terminal of the 4th present invention which has an IGMP management part which deletes the corresponding multicast address currently carried out.

  According to a sixth aspect of the present invention, when the IGMP management unit receives a request to join the multicast address before the timer expires, the user terminal or a user terminal different from the user terminal drives the timer. Is a client terminal of the fifth aspect of the present invention.

A seventh aspect of the present invention is a multicast communication control method for controlling a multicast packet by using a client terminal connected under the control of a user terminal capable of communicating with a multicast compatible router,
In the client terminal,
Registering the multicast address with a multicast address management unit upon receiving a request to join the multicast address transmitted by the user terminal;
When receiving a withdrawal request for the multicast address to which the user terminal is participating, deleting a corresponding multicast address registered in the multicast address management unit;
If the received data is multicast packet data that is not registered in the multicast address management unit, a step of discarding is executed.
This is a multicast communication control method.

  According to an eighth aspect of the present invention, in the multicast communication control method according to the seventh aspect of the present invention, upon receiving a request for participation in the multicast address transmitted by the user terminal, the step of registering the multicast address in a multicast address management unit; When a withdrawal request for the multicast address to which the user terminal participates is received, the step of deleting the corresponding multicast address registered in the multicast address management unit; and the received data is the multicast address management unit A program for causing a computer to execute a step of discarding multicast packet data that is not registered in.

  The ninth aspect of the present invention is a recording medium that records the program of the eighth aspect of the present invention, and is a recording medium that can be processed by a computer.

  According to the present invention, since it is possible to prevent a useless multicast packet from flowing into a user's home, it is possible to prevent a useless load from being applied to the home network.

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

(Embodiment 1)
FIG. 1 is a diagram schematically showing a configuration of a multicast system according to Embodiment 1 of the present invention. A router 2 that performs packet routing is connected to the multicast server 1. Under the router 2, a master 3 that is a main terminal of coaxial communication and client terminals 4a and 4b are connected by a coaxial cable. Further, user terminals 5a to 5c are connected under the client terminal 4a, and a user terminal 5d is connected under the client terminal 4b. Here, the user terminal is, for example, a personal computer. Needless to say, other terminals may be used instead of the personal computer.

  In the first embodiment, an example will be described in which a user terminal connected to a client terminal views a video distributed from a multicast server 1 using a multicast packet in a system using a coaxial cable (for example, cable Internet). .

  The configuration of the client terminal in the first embodiment will be described. FIG. 2 is a configuration diagram thereof. The client terminals 4a and 4b installed in the subscriber's home include a coaxial interface (hereinafter simply referred to as I / F) 21 that connects a coaxial cable connected to the master 3, and a coaxial transmission / reception processing unit that processes coaxial communication. 22, a transfer control unit 23 that controls data transfer, an IGMP management unit 24 that is arranged in the transfer control unit 23 and determines and manages an IGMP control packet, and also in the transfer control unit 23. Filter processing unit 25 for filtering packet data to be arranged and transferred, multicast address management unit 26 for managing a multicast address to which user terminals 5a to 5d connected under control belong, and data communication transmission / reception for processing data communication The processing unit 27 and the communication I / F 28 are included. The coaxial I / F 21 is an example of the first I / F of the present invention, and the communication I / F 28 is an example of the second I / F of the present invention. The coaxial transmission / reception processing unit 22 is an example of a first transmission / reception processing unit of the present invention, and the communication transmission / reception processing unit 27 is an example of a second transmission / reception processing unit of the present invention.

  First, the operation of the client terminal until the user terminal views the multicast video will be described using a flowchart. Here, the case of the user terminal 5d connected under the client terminal 4b (when there is one user connected under the client terminal) will be described.

  When the user selects a program that the user wants to view on, for example, the WEB of the personal computer, the user terminal 5d transfers to the router 2 the multicast address (here, 227.0.0.1) corresponding to the program that the user wants to view. The request is transmitted to the communication I / F 28 of the client 4b by an IGMP JOIN message.

  Hereinafter, the operation of the client terminal 4b will be described with reference to the flowchart of FIG. When receiving a packet from the user terminal 5d via the communication I / F 28 (step 301), the IGMP management unit 24 of the client terminal 4b determines whether the packet is an IGMP message (step 302). In response to the result, the filter processing unit 25 transfers (passes) the packet to the coaxial I / F 21 without processing if the packet is not an IGMP message (step 307).

  On the other hand, if the packet is an IGMP message, the IGMP management unit 24 next determines whether it is an IGMP JOIN message (step 303). If the packet is an IGMP JOIN message, the IGMP management unit 24 registers the multicast address (227.0.0.1) corresponding to the desired program requested by the user terminal 5d in the multicast address management unit 26.

  After the registration is completed, the filter processing unit 25 transfers (passes) the packet to the coaxial I / F 21 (step 307). When the router 2 receives the IGMP JOIN message via the master 3, the multicast packet is sent from the multicast server 1 (the destination is 227.0.0.1) to the master 3 side, that is, the coaxial network. To the side.

  Next, the client terminal 4b when a multicast packet is received will be described with reference to FIG. The IGMP management unit 24 of the client terminal 4b that has received the packet (step 401) first determines whether the packet is a multicast packet (step 402). If the packet is not a multicast packet, the filter processing unit 25 transfers (passes) the packet to the communication I / F 28 without performing any processing (step 406).

  On the other hand, if the packet is a multicast packet, the filter processing unit 25 of the client device 4b obtains a registered multicast address list from the multicast address management unit 26 (step 403). It is determined whether the destination address of the received multicast packet matches one of the acquired multicast address lists (step 404). If they do not match, the multicast packet is discarded without being transferred to the communication I / F 28 (step 405). On the other hand, if they match, the received multicast packet is transferred to the communication I / F 28 (step 406).

  By following such a procedure, the user can transfer only the multicast packet of the program selected by the user, and no unnecessary packet flows.

  Next, a case where the user terminal 5d finishes viewing the program will be described. When the user terminal 5d finishes viewing the program, the user terminal 5d transmits a withdrawal request to the router 2 for the multicast address (in this example, 227.0.0.1) corresponding to the terminated program by an IGMP LEAVE message. Next, the operation of the client terminal 4b that has received the IGMP LEAVE message transmitted by the user terminal 5d will be described with reference to FIG.

  When receiving the packet from the user terminal 5d through the communication I / F 28 (step 301), the IGMP management unit 24 of the client terminal 4b determines whether the data of the packet is an IGMP message (step 302). If the packet is not an IGMP message, the filter processing unit 25 transfers (passes) the packet to the coaxial I / F 21 without processing anything (step 307). On the other hand, if the packet is an IGMP message (step 302) and not an IGMP JOIN message (step 303), the IGMP management unit 24 determines whether it is an IGMP LEAVE message (step 304). If the packet is not an IGMP LEAVE message, the filter processing unit 25 transfers (passes) the packet to the coaxial I / F 21 without performing any processing (step 307). On the other hand, if the packet is an IGMP LEAVE message, the IGMP management unit 24 deletes the corresponding multicast address registered in the multicast address management unit 26 (step 306).

  The filter processing unit 25 of the client terminal 4b transfers (passes) the packet to the coaxial I / F 21 after the deletion procedure of the IGMP management unit 24 is completed (step 307).

  By following the above procedure, the packet filtering is immediately applied by deleting the multicast address registration in the multicast address management unit 26 of the client terminal 4b at the moment when the user terminal 5d transmits the IGMP LEAVE message. Therefore, it is possible to prevent a useless packet viewed by other users in the same cell from flowing in immediately. Here, the other users in the same cell are the same coaxial communication, that is, users who use the other user terminals 5a to 5c connected to the same master 3 and receive the same multicast address) .

(Embodiment 2)
Next, a second embodiment of the present invention will be described. In the second embodiment, a case is considered in which a user terminal connected to a client terminal views a video distributed from a multicast server 1 by a multicast packet in a system using a coaxial cable (for example, cable Internet).

  The configuration of the client terminal in the second embodiment shown in FIG. 5 will be described. The client terminals 4a and 4b installed in the subscriber's homes have a coaxial I / F 51 that connects a coaxial cable connected to the master 3, a coaxial transmission / reception processing unit 52 that processes coaxial communication, and a transfer that controls data transfer. An IGMP management unit 54 that is arranged in the control unit 53 and the transfer control unit and determines that the packet is an IGMP control packet, and a filter process that is also arranged in the transfer control unit 23 and performs a filtering process on packet data to be transferred. Data communication processing with the unit 55, the multicast address management unit 56 that manages the multicast address to which the user terminals 5a to 5d connected to the subordinate belong, the timer management unit 57 that manages the timer when deleting the multicast address to which the user belongs The data communication transmission / reception processing unit 58 and the communication I / F 59 are configured.

  First, the operation of the client terminal until the user terminal views the multicast video will be described using a flowchart. In this example, consider the case of the user terminal 5a connected under the client terminal 4a (when there are a plurality of users connected under the client terminal).

  When the user selects a program that the user wants to watch on, for example, the WEB of the personal computer, the user terminal 5a sends to the router 2 the multicast address (227.0.0.1 in this example) corresponding to the program that the user wants to view. The transfer request is transmitted to the communication I / F 59 of the client terminal 4a by an IGMP JOIN message.

  Hereinafter, the operation of the client terminal 4a will be described with reference to the flowchart of FIG. When receiving the packet from the user terminal 5a via the communication I / F 59 (step 601), the IGMP management unit 54 of the client terminal 4a determines whether the packet is an IGMP message (step 602). In response to the result, the filter processing unit 55 transfers (passes) the packet to the coaxial I / F 51 without processing the packet if it is not an IGMP message (step 609).

  On the other hand, if the packet is an IGMP message, the IGMP management unit 54 determines whether it is an IGMP JOIN message (step 603). If the packet is an IGMP JOIN message, the IGMP management unit 54 determines whether a timer for the multicast address of the IGMP JOIN message is activated (step 605).

  If the timer has not been started, the IGMP management unit 54 registers the multicast address (227.0.0.1) requested by the user terminal 5a in the multicast address management unit 26 (step 606). After completing the registration, the filter processing unit 55 transfers (passes) the packet to the coaxial I / F 51 (step 609).

  On the other hand, if the timer has been started, it is determined that there is a user terminal to be deleted under its own client terminal 4a, and the IGMP management unit 54 deletes the deletion timer (step 608).

  That is, the timer driving is stopped before its expiration. After completion of the timer deletion, the filter processing unit 55 transfers (passes) the packet to the coaxial I / F 51 (step 609).

  When the router 2 receives the IGMP JOIN message, the multicast packet from the multicast server 1 (the destination is 227.0.0.1) is transferred to the coaxial network side thereafter.

  Next, the client terminal 4a when receiving a multicast packet will be described with reference to FIG. The IGMP management unit 54 of the client terminal 4a that has received the packet (401) first determines whether the packet is a multicast packet (step 402). If the packet is multicast, the filter processing unit 55 transfers (passes) the packet to the communication I / F 59 without performing any processing (step 406).

  On the other hand, if the packet is a multicast packet, the filter processing unit 55 of the client device 4a obtains a registered multicast address list from the multicast address management unit 56 (step 403). It is determined whether the destination address of the received multicast packet matches one of the acquired multicast address lists (step 404). If they do not match, the multicast packet is discarded without being transferred to the communication I / F 59 (step 405). On the other hand, if they match, the multicast packet is transferred to the communication I / F 59 (step 406).

  By following such a procedure, the user can transfer only the multicast packet of the program selected by the user, and no unnecessary packet flows.

  Next, a case where the user terminal 5a finishes viewing the program will be described. When the user terminal 5a finishes viewing the program, the user terminal 5a transmits a withdrawal request to the router 2 for the multicast address (227.0.0.1 in the present example) corresponding to the terminated program by an IGMP LEAVE message. Next, the operation of the client terminal 4a that has received the IGMP LEAVE message transmitted by the user terminal 5a will be described with reference to FIG.

  When the client terminal 4a receives a packet from the user terminal 5a via the communication I / F 59 (step 601), the client terminal 4a determines whether the packet is an IGMP message (step 602). If it is not an IGMP message, the packet is transferred (passed) to the coaxial I / F 51 without any processing (step 610). On the other hand, if the packet is not an IGMP JOIN message, it is determined whether it is an IGMP LEAVE message (step 604). If the message is not an IGMP LEAVE message, the packet is transferred (passed) to the coaxial I / F 51 without any processing (step 610).

  On the other hand, if the packet is an IGMP LEAVE message in step 604, the IGMP management unit 54 starts a timer for deleting the multicast address registered in the multicast address management unit 56 (step 607). After the start of the timer is completed, the filter processing unit 55 transfers (passes) the packet of the IGMP LEAVE message to the coaxial I / F 51 (step 610).

  Next, the started timer process will be described with reference to the flowchart of FIG. It is determined whether the timer has expired (step 701). If the timer has not expired, the timer is updated (step 702). If the timer has expired, the IGMP management unit 54 deletes the target multicast address (step 703). ).

  By following the above procedure, the multicast address filter is not deleted at the moment when the user terminal 5a transmits the IGMP LEAVE message, a timer value is set once, the timer is started, and the filter is deleted after a predetermined time has elapsed. Thus, since the user terminal existing under the same client for the IGMP Specific Query that is transmitted after the router 2 receives the IGMP LEAVE message can be provided with an opportunity to transmit the IGMP JOIN message, a plurality of subordinates can be provided under the client terminal 4a. Efficient distribution can be performed when there is a user terminal.

  In the configuration of the second embodiment of the present invention, by setting the set time of the timer to zero, when there is one user terminal connected to the client terminal, useless operation of waiting for a certain time Can be eliminated. By using zero setting in this way, the configuration of the second embodiment can also serve as the case of the first embodiment.

  The program of the present invention is a program for causing a computer to execute all or part of the above-described multicast communication control method of the present invention, and is a program that operates in cooperation with the computer.

  The recording medium of the present invention is a recording medium on which the above-described program of the present invention is recorded. The recording medium is readable by a computer, and the read program executes the function in cooperation with the computer. is there.

  Further, one usage form of the program of the present invention may be an aspect in which the program is recorded on a recording medium such as a ROM readable by a computer and operates in cooperation with the computer.

  Also, one use form of the program of the present invention is an aspect in which the program is transmitted through a transmission medium such as the Internet and a transmission medium such as light, radio wave, and sound wave, read by a computer, and operates in cooperation with the computer. Also good.

  The computer of the present invention described above is not limited to pure hardware such as a CPU, and may include firmware, an OS, and peripheral devices.

  As described above, the configuration of the present invention may be realized by software or hardware.

  The client terminal according to the present invention is useful for a multicast access system using a coaxial cable such as a cable Internet because the network load on the user terminal is reduced.

Schematic diagram of multicast system in Embodiments 1 and 2 of the present invention Configuration diagram of client terminal according to Embodiment 1 of the present invention Flowchart of uplink packet reception processing of client terminal in Embodiment 1 of the present invention Flowchart of downlink packet reception processing of client terminal in Embodiment 1 of the present invention Configuration diagram of client terminal according to Embodiment 2 of the present invention Flowchart of uplink packet reception processing of client terminal in Embodiment 2 of the present invention Flowchart of downlink packet reception processing of client terminal in Embodiment 2 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multicast server 2 Router 3 Master 4a-b Client terminal 5a-d User terminal 21 Coaxial I / F
22 Coaxial transmission / reception processing unit 23 Transfer control unit 24 IGMP management unit 25 Filter processing unit 26 Multicast address management unit 27 Communication transmission / reception processing unit 28 Communication I / F
51 Coaxial I / F
52 Coaxial transmission / reception processing unit 53 Transfer control unit 54 IGMP management unit 55 Filter processing unit 56 Multicast address management unit 57 Timer management unit 58 Communication transmission / reception processing unit 59 Communication I / F

Claims (9)

A client terminal to which a user terminal can be connected under the control of a multicast-compatible router,
A first interface capable of communicating with the router;
A first transmission / reception processing unit connected to the first interface for processing data communication;
A transfer control unit connected to the first transmission / reception processing unit to control data transfer;
A multicast address management unit connected to the transfer control unit and managing a multicast address in which the user terminal participates;
A second transmission / reception processing unit connected to the transfer control unit for processing data communication;
A second interface connected to the second transmission / reception processing unit and capable of communicating with the user terminal,
The transfer control unit manages the multicast address management unit according to information including a join request or withdrawal request regarding a multicast address received through the second interface, and uses the multicast address management unit to transmit data to be received Perform filtering,
Client terminal.   The client terminal according to claim 1, wherein the transfer control unit includes a filter processing unit that discards data received when the received data is multicast packet data not registered in the multicast address management unit.   When the transfer control unit receives a request for participation in the multicast address transmitted by the user terminal, the transfer control unit registers the multicast address with the multicast address management unit, and withdraws from the multicast address in which the user terminal participates The client terminal according to claim 1, further comprising an IGMP management unit that deletes a corresponding multicast address registered in the multicast address management unit when a request is received.   The client terminal according to claim 1, further comprising a timer management unit that manages a timer for deleting a multicast address to which the user terminal of the multicast address management unit belongs.   When the transfer control unit receives a request for participation in the multicast address transmitted by the user terminal, the transfer control unit registers the multicast address with the multicast address management unit, and withdraws from the multicast address in which the user terminal participates When a request is received, the timer for deleting the corresponding multicast address registered in the multicast address management unit is started, and when the timer expires, the corresponding multicast address registered in the multicast address management unit The client terminal according to claim 4, further comprising an IGMP management unit that deletes.   The IGMP management unit stops driving of the timer when the user terminal or a user terminal different from the user terminal receives a participation request for the multicast address before the timer expires. The client terminal described. A multicast communication control method for controlling a multicast packet by using a client terminal connected under the control of a user terminal capable of communicating with a multicast-compatible router,
In the client terminal,
Registering the multicast address with a multicast address management unit upon receiving a request to join the multicast address transmitted by the user terminal;
When receiving a withdrawal request for the multicast address to which the user terminal is participating, deleting a corresponding multicast address registered in the multicast address management unit;
If the received data is multicast packet data that is not registered in the multicast address management unit, a step of discarding is executed.
Multicast communication control method.   8. The multicast communication control method according to claim 7, wherein when receiving a request to join the multicast address transmitted by the user terminal, the step of registering the multicast address with a multicast address management unit; And a step of deleting a corresponding multicast address registered in the multicast address management unit when the withdrawal request for the multicast address is received, and multicast packet data in which the received data is not registered in the multicast address management unit In the case of, a program for causing the computer to execute a step of discarding.   A recording medium on which the program according to claim 8 is recorded, wherein the recording medium can be processed by a computer.

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