JP4476839B2 - Data distribution system, relay device, and data distribution method - Google Patents

Description

  The present invention relates to a data distribution system, a relay device, and a data distribution method, and more particularly to a data distribution system that performs multicast distribution in a packet communication network, a relay device used for the data distribution method, and a data distribution method.

IP multicast received by a plurality of specific receiving device groups identified by IP addresses is a one-to-many communication in which a sender can transmit to a plurality of receiving devices by transmitting one packet, such as stream distribution. This is an effective distribution means for the broadcast type service.
However, in order to realize data distribution by IP multicast, since all routers on the distribution route from the sender to the receiver need to support multicast, there is a problem that it cannot be used on the current Internet.

  Focusing on this point, there is mrouted, which is a routing method using tunnel technology, as a method for realizing multicast communication in the Internet section (for example, see Non-Patent Document 1). In mrouted, a multicast packet is encapsulated in a unicast packet to enable transmission / reception of the multicast packet via a unicast network. As a result, the multicast-compatible networks are connected to each other using the mrouted as a tunnel. As a result, end-to-end multicast distribution can be performed by substituting an IP unicast tunnel in the Internet section that does not support IP multicast.

  This will be described with reference to FIG. FIG. 7 is a block diagram illustrating a configuration example of a data distribution system that realizes multicast using a tunnel based on IP unicast. In the figure, a data distribution system includes a first network 101 that can transfer multicast packets, an Internet 102 that is adjacent to the first network 101 and cannot transfer multicast packets, and a second network. The third network 103, the fourth network 104, and the fifth network 105 that are adjacent to the Internet 102 and can transfer multicast packets are configured.

The first network 101 is provided with a connected multicast distribution server (Send) 106 and a relay device (Mrelay) 107 that is located between the Internet 102 and relays packet data with other networks. It has been.
The third network 103 is provided with a relay device (Mrelay) 108 and a receiving device (Recv) 109 that are located between the Internet 102 and relay packet data with other networks.

The fourth network 104 is provided with a relay device (Mrelay) 110 and a receiving device (Recv) 111 that are located between the Internet 102 and relay packet data with other networks.
The fifth network 105 is provided with a relay device (Mrelay) 112 and a receiving device (Recv) 113 that are located between the Internet 102 and relay packet data with other networks.

  In such a configuration, when the same multicast data is distributed from the multicast distribution server 106 to the receiving device 109, the receiving device 111, and the receiving device 113, the data is distributed in the following procedure. First, the relay device 107 receives a multicast packet transmitted from the multicast distribution server 106 (S71), and duplicates data in the packet. Then, it is transferred as a unicast packet using the tunnel technology to the relay device 108, the relay device 110, and the relay device 112 by unicast (S72). Then, the relay device 108 restores the unicast packet including the distribution data received from the relay device 107 to the original multicast packet and transmits it to the network 103, and the reception device 109 receives it (S73a). In addition, the relay device 110 restores the unicast packet including the distribution data received from the relay device 107 to the original multicast packet and transmits it within the network 104, and the reception device 111 receives this (S73b). Then, the relay device 112 restores the unicast packet including the distribution data received from the relay device 107 to the original multicast packet and transmits it to the network 105, and the receiving device 113 receives it (S73c).

As described above, end-to-end multicast distribution can be performed from the multicast distribution server 106 to the reception device 109, the reception device 111, and the reception device 113.
Naoto Fujii, “IP Multicast Technology”, [online], December 15, 1999, IAI Media Communications, Inc. [searched February 20, 2005], Internet <URL: http: //www.nic. ad.jp/en/materials/iw/1999/notes/C11.PDF>

In the data distribution system described above, the relay device 107 that is the relay source needs to replicate and transmit the distribution data to a plurality of relay destinations. Increased network usage load.
When relaying multicast distribution data using unicast for the Internet section, if the number of relay destinations to which distribution data is transferred increases at the relay source, the relay device at the relay source replicates the distribution data and transfers it to multiple relay destinations. To do. For this reason, there is a problem that the load due to the duplication processing of the relay device at the relay source and the load on the network increase.
The present invention has been made in view of the above-described problems. When the number of distribution data relay destinations increases, the same distribution data received at the relay destination is re-transferred to another relay destination. An object is to provide a data distribution system, a relay device, and a data distribution method capable of distributing the original load.

The relay apparatus according to claim 1 of the present invention tunnels network sections incapable of multicasting, thereby distributing distribution data sent from a distribution source apparatus in a multicast-capable network to apparatuses in the multicast-capable network. A relay device that relays and exists in a network other than the network where the data distribution source device exists, exists in a network other than the network where the distribution data distribution device exists , and is sent to the distribution source device Data transmission means for transmitting the distribution data to the request source of the relay start request in response to a relay start request transmitted from another relay device that has received the relay start response from the distribution source device in response to the relay start request only including, the relay start response, place the load of the distribution source device exceeds the threshold value Characterized in that it is sent to. According to such a configuration, when the load and the network usage band due to the relay processing of the relay device of the network in which the distribution source device exists increase, the relay device that exists in another network as the relay source of the same distribution data. By specifying and relaying the distribution data received by the relay device to another relay device, the load on the relay device can be reduced and the load can be distributed. Further, when the load on the distribution source device increases, it can be notified to the distribution request source and the load can be distributed to other devices.

The relay device according to a second aspect of the present invention is the relay device according to the first aspect , wherein the data transmission means sends the distribution data to the request source of the relay stop request in response to the relay stop request from the other relay device. The transmission is stopped. According to such a configuration, the relay can be stopped even during the relay of the distribution data.

The relay apparatus according to claim 3 of the present invention tunnels network sections where multicast is not possible, thereby distributing distribution data sent from a distribution source apparatus existing in a multicast-capable network to apparatuses existing in the multicast-capable network. A relay device that is relayed and exists in a network other than the network where the data distribution source device exists, to another relay device that exists in a network other than the network where the distribution data distribution device exists. A request transmission unit configured to transmit a relay start request for the distribution data after receiving a relay start response from the distribution source device in response to a relay start request to the distribution source device , wherein the relay start response includes the distribution source device; sent when the load exceeds the threshold value, in response to the relay start request Characterized by receiving the distribution data transmitted from the serial another relay device. According to such a configuration, when the load and the network usage band due to the relay processing of the relay device of the network in which the distribution source device exists increase, the relay device that exists in another network as the relay source of the same distribution data. By specifying and relaying the distribution data received by the relay device to another relay device, the load on the relay device can be reduced and the load can be distributed. Further, when the load on the distribution source device increases, it can be notified to the distribution request source and the load can be distributed to other devices.

The relay apparatus according to claim 4 of the present invention is characterized in that, in claim 3 , the request transmission means requests the other relay apparatus to stop transmitting the distribution data. According to such a configuration, the relay can be stopped even during the relay of the distribution data.

The relay device according to claim 5 of the present invention is the relay device according to any one of claims 1 to 4 , wherein a table associating an address in the multicast-capable network with an address in the network incapable of multicasting is provided. In addition, the network section in which the multicast is impossible is tunneled by referring to the table and converting the address. According to such a configuration, a multicast address and a unicast address can be mutually converted by referring to the table, and tunneling can be easily realized.

According to a sixth aspect of the present invention, there is provided a data distribution method in which distribution data sent from a distribution source apparatus existing in a multicast-capable network is present in a multicast-capable network by tunneling network sections incapable of multicasting. A data distribution method for relaying to a network, wherein the distribution data is present in a network other than the network where the distribution data source device exists, and receives a relay start response from the distribution source device in response to a relay start request to the distribution source device In response to the relay start request transmitted from the relay device, the distribution data is transmitted to the request source of the relay start request, and the relay start response is transmitted when the load of the distribution source device exceeds a threshold value. It is characterized by being. According to such a configuration, when the load and the network usage band due to the relay processing of the relay device of the network in which the distribution source device exists increase, the relay device that exists in another network as the relay source of the same distribution data. By specifying and relaying the distribution data received by the relay device to another relay device, the load on the relay device can be reduced and the load can be distributed.

  According to the present invention, a relay device that relays the same distribution data when performing end-to-end multicast distribution instead of unicast using tunnel technology or the like even in a network that does not support multicast. When the relay processing load or network usage rate increases, the relay data received by the relay destination relay device that receives the same distribution data is relayed again to the new relay destination relay device. There is an effect that the load of the original relay device can be distributed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings referred to in the following description, the same parts as those in the other drawings are denoted by the same reference numerals.
(System configuration)
FIG. 1 is a block diagram showing a configuration of a data distribution system according to an embodiment of the present invention. 7, the data distribution system according to the present embodiment differs from the configuration in FIG. 7 in that it exists in networks 103, 104, and 105 other than the network 101 in which the distribution server 106 that is the distribution data distribution source apparatus exists. The relay apparatuses 207, 208, 210, and 212 are used to transmit distribution data to the request source of the relay start request in response to the relay start request from the relay apparatus.

Each of these relay devices 207, 208, 210, and 212 is configured by a computer having hardware resources such as a CPU (Central Processing Unit), a storage device, and an input / output device, and software resources stored in the storage device. Yes.
In this embodiment, since IP multicast cannot be transferred in the Internet 102, end-to-end multicast data across the Internet 102 using the data relay function between the relay device 207 and the relay devices 208, 210, and 212 is used. Perform the transfer.
In FIG. 1, there are actually a large number of networks, distribution servers, relay devices, and receiving devices that can transfer multicast packets.

(Relay device 207)
Here, a configuration example of the relay device 207 will be described with reference to FIG. The relay device 207 is a router, for example.
As shown in the figure, the relay device 207 includes a relay load monitoring unit 403, a relay request input / output unit 404, a relay data processing unit 405, and a relay information management unit 406 that are realized by the CPU executing a program. And a relay information storage unit 407 and a data input / output unit 408 including an interface device with the network 101 and the Internet 102.

  The relay load monitoring unit 403 monitors the relay processing load and the network usage load. When the load is small, the relay device 207 determines to perform data relay, and the relay data processing unit 405 performs data relay for the relay device that has made the relay start request. When the load is large, a relay start response is notified to the relay apparatus that has made the relay start request so that the relay data is received from the transmitting relay apparatus. Note that the magnitude of the load is compared with, for example, a predetermined threshold value, and it is determined that the load has increased when the threshold value is exceeded.

  The relay request input / output unit 404 receives a relay start request from another relay device. Further, the relay request input / output unit 404 stores the IP address and UDP port number of the multicast group notified by the relay start request, and the IP address and UDP port number used for receiving relay data, respectively. These pieces of information are reflected in the relay information table stored in the relay information storage unit 407 by the relay information management unit 406.

In this example, when the relay load monitoring unit 403 determines that the load is large, the relay device 207 requests the relay device that has made a relay start request so that the relay device 207 receives the relay data from the relay device 208 that is transmitting the relay data. The relay request input / output unit 404 transmits a relay start response.
The relay data processing unit 405 converts the multicast distribution packet received from the network 101 into a unicast packet based on the relay information table stored in the relay information storage unit 407 and transmits it to the Internet 102 by unicast. Also, the relay data processing unit 405 converts relay data from another relay apparatus received from the Internet 102 by unicast into a multicast packet and transmits it to the network 101.

The relay information management unit 406 adds / deletes the relay information table stored in the relay information storage unit 407 based on the relay start request from another relay device and the multicast group of the multicast packet transmitted from the distribution server 106. Etc. are managed.
The relay information storage unit 407 stores a correspondence relationship of information used when the data relay processing unit performs packet conversion during relay as a relay information table. A configuration example of the relay information table is shown in FIG. As shown in the figure, the relay information table is configured to associate the IP address and UDP port number of the multicast address with the IP address and UDP port number of the unicast address.
Returning to FIG. 2, the data input / output unit 408 provides an interface between the network 101 and the Internet 102 and each functional unit, and data with the distribution server 106, other relay devices, and receiving devices via the network 101 and the Internet 102. Data transmission / reception and data input / output between functional units.

(Relay device 208)
Next, a configuration example of the relay device 208 will be described with reference to FIG.
As shown in the figure, the relay device 208 includes a relay load monitoring unit 503, a relay request input / output unit 504, a relay data processing unit 505, and a relay information management unit 506 that are realized by the CPU executing a program. And a reception request processing unit 508, a relay information storage unit 507, and a data input / output unit 509 including an interface device with the Internet 102 and the network 103.

  The relay load monitoring unit 503 monitors the relay processing load and the network usage load. When the load is small, the relay device 210 determines to perform data relay, and the relay data processing unit 505 performs data relay to the relay device that has made a relay start request. When the load is large, a relay start response is notified to the relay apparatus that has made the relay start request so as to receive relay data from the relay apparatus 208 that is transmitting.

  The relay request input / output unit 504 receives a relay start request from another relay device. Next, the relay request input / output unit 504 stores the IP address and UDP port number of the notified multicast group, and the IP address and UDP port number used to receive the relay data, respectively. . These pieces of information are reflected in the relay information storage unit 507 by the relay information management unit 506.

  When the relay load monitoring unit 503 determines that the load is large, the relay request input / output unit 504 starts relaying so that the relay device 207 receives relay data from another relay device that is transmitting relay data. A relay start response is transmitted to the requesting relay device. Further, in order to relay the distribution data of the multicast group requested from the receiving device 111, a relay start request is made to the relay device 207.

  Based on the relay information table of the relay information management unit 506, the relay data processing unit 505 converts relay data from another data device received from the Internet 102 by unicast into a multicast packet, and transmits the multicast packet in the network 103. Send. Here, when the relay device 208 transfers distribution data to another relay device, the received data is copied, converted into a unicast packet addressed to another relay device, and transmitted to the Internet 102 by unicast. Forward.

The relay information management unit 506 manages addition / deletion to / from the relay information table stored in the relay information storage unit 507 based on a relay start response from another relay device and a reception request from the receiving device.
The relay information storage unit 507 stores a correspondence relationship of information used when the relay data processing unit 505 performs packet conversion when relaying, as a relay information table (see FIG. 3).

The reception request processing unit 508 receives a reception start request from the reception device 109, and the relay request input / output unit 504 makes a relay start request based on the notified IP address and UDP port number of the multicast group.
The data input / output unit 509 provides an interface between the Internet 102 and the network 103 and each functional unit, transmits / receives data to / from other relay devices and receiving devices via the Internet 102 and the network 103, and data between each functional unit. I / O is performed.

(Relay device 210)
Next, a configuration example of the relay device 210 will be described with reference to FIG.
As shown in the figure, the relay device 210 includes a relay request processing unit 603, a relay data processing unit 604, a relay information management unit 605, and a reception request processing unit 607, which are realized by the CPU executing a program. The relay information storage unit 606 and the data input / output unit 608 including an interface device with the Internet 102 and the network 104 are configured.

The relay request processing unit 603 makes a relay start request to the relay device 207 in order to relay the distribution data of the multicast group requested from the receiving device 111.
Based on the relay information table (see FIG. 3) of the relay information management unit 605, the relay data processing unit 604 converts the relay data from another data device received from the Internet 102 by unicast into a multicast packet, The multicast packet is transmitted to.

The relay information management unit 605 manages addition / deletion to / from the relay information table stored in the relay information storage unit 606 based on a relay start response from another relay device and a reception start request from the reception device 113.
The relay information storage unit 606 stores a correspondence relationship of information used when the relay data processing unit 604 performs packet conversion during relay as a relay information table.

The reception request processing unit 607 receives the reception start request from the reception device 113, and the relay request processing unit 603 makes a relay start request based on the notified IP address and UDP port number of the multicast group.
The data input / output unit 608 provides an interface between the Internet 102 and the network 104 and each functional unit, transmits / receives data to / from other relay devices and receiving devices via the Internet 102 and the network 104, and between each functional unit. Input and output data.
The relay device 212 and other relay devices (not shown) have the same configuration as the relay device 208 and the like.

(System operation example)
An example of the operation in the data distribution system having the above configuration will be described with reference to FIGS.
In FIG. 6, the distribution server 106 distributes data as needed to the relay device 208 via the relay device 207 (S01, S02,..., S07...). In this distribution, a network section incapable of multicasting is tunneled by unicast to relay distribution data sent from a distribution source apparatus existing in a multicast-capable network to apparatuses existing in the multicast-capable network. As shown in FIG. 1, this distribution is performed not only from the relay device 207 to the relay device 208 but also to the relay device 212 (S12). Then, the data is transmitted from the relay device 208 to the reception device 109 (S73a) and transmitted from the relay device 212 to the reception device 113 (S73c).

Returning to FIG. 6, the reception device (for example, wireless LAN terminal) 111 transmits a multicast data reception start request when data distribution is desired (S 1). The relay device (for example, the wireless LAN base station) 210 that has received this reception start request sends a relay start request to the relay device 207 (S2), tells that the receiving device 111 exists under it, and Notify IP address and UDP port number for unicast packet standby.

  Here, when the relay device 207 determines that its own relay processing load (CPU usage rate, etc.) and network load (network usage rate, etc.) are large, so as to receive the relay data from the relay device 208, A relay start response is notified to the relay device 210 (S3). The relay device 210 transmits a relay start request to the relay device 208 based on the received relay start response (S4), tells that the receiving device 111 exists under the subordinate, and has its own IP address and unicast packet. Notify the UDP port number for standby.

The relay device 208 starts unicast relay based on the relay destination information obtained by the relay start request (S4) (S5, S6). Then, the relay device 210 transmits the received unicast packet again as a multicast packet to the receiving device 111 (S7). As shown in FIG. 1, this relay is performed from the relay device 208 to the relay device 210 (S14), and further from the relay device 210 to the reception device 111 (S73b).

Returning to FIG. 6, if the receiving device 111 desires to stop receiving distribution data for reasons such as leaving the multicast group of the network 104, the receiving device 111 transmits a reception stop request (S 8). When receiving the reception stop request from the subordinate receiving device, the relay device 208 sends a relay stop request to the relay device 208 (S9). Thereby, the relay by the unicast between the relay apparatus 208 and the relay apparatus 210 stops.
According to the above procedure, when the relay load of the relay device 207 increases, the relay data received by the relay device 208 is relayed again, thereby reducing the load on the relay device 207.
Note that the delivery data is transferred to another relay device (not shown) by the same processing as described above.

(Data delivery method)
In the data distribution system described above, the following data distribution method is realized. That is, a data distribution method for relaying distribution data sent from a distribution source device existing in a multicast-capable network to a device existing in a multicast-capable network by tunneling a network section where multicast is impossible, A relay start request transmitted from a relay device that is present in a network other than the network in which the distribution source device of the distribution data exists and that has received a relay start response from the distribution source device in response to a relay start request to the distribution source device. In response, the data distribution method is realized in which the distribution data is transmitted to the request source of the relay start request, and the relay start response is transmitted when the load of the distribution source device exceeds a threshold value . According to such a data distribution method, when the load and the network use band increase due to the relay processing of the relay device of the network where the distribution source device exists, the relay existing in another network as the relay source of the same distribution data By designating a device and relaying the distribution data received by the relay device to another relay device, the load on the relay device can be reduced and the load can be distributed.

  The present invention can be used when distributing the load of a relay device that relays distribution data from a distribution server.

It is a block diagram which shows the structure of the data delivery system which concerns on embodiment of this invention. 3 is a block diagram illustrating an exemplary functional configuration of a relay device 207. FIG. It is a figure which shows the example of a relay information table. 3 is a block diagram illustrating a functional configuration example of a relay device 208. FIG. 3 is a block diagram illustrating an exemplary functional configuration of a relay device 210. FIG. It is a sequence diagram which shows a delivery data relay procedure. It is a block diagram which shows the structure of the conventional data delivery system.

Explanation of symbols

101, 103, 104, 105 Network 102 Internet 106 Distribution server 107, 108, 110, 112
207, 208, 210, 212 Relay devices 109, 111, 113 Receivers 403, 503 Relay load monitoring units 404, 504 Relay request input / output units 405, 505, 604 Relay data processing units 406, 506, 605 Relay information management unit 407 , 507, 606 Relay information storage unit 408, 509, 608 Data input / output unit 508, 607 Reception request processing unit 603 Relay request processing unit

Claims (6)

By tunneling a network section incapable of multicasting, the distribution data sent from the distribution source device existing in the multicast-capable network is relayed to the device existing in the multicast-capable network, and the data distribution source device A relay apparatus that exists in a network other than the network where the distribution data exists, and is present in a network other than the network where the distribution data distribution source apparatus exists, and from the distribution source apparatus to the relay start request to the distribution source apparatus In response to a relay start request transmitted from another relay apparatus that has received the relay start response, the relay start request includes data transmission means for transmitting the distribution data to a request source of the relay start request. Relay that is sent when the load on the source device exceeds the threshold Location. 2. The relay apparatus according to claim 1, wherein the data transmission unit stops transmission of the distribution data to a request source of the relay stop request in response to a relay stop request from the other relay apparatus. . By relaying a network section incapable of multicasting, the distribution data sent from the distribution source device existing in the multicast-capable network is relayed to the device existing in the multicast-capable network, and the data distribution source device A relay apparatus that exists in a network other than the network in which the distribution data is distributed, and is in response to a relay start request to the distribution source apparatus to another relay apparatus that exists in a network other than the network in which the distribution data distribution apparatus exists. After receiving a relay start response from the distribution source device, the device includes request transmission means for transmitting a relay start request for the distribution data, and the relay start response is transmitted when a load on the distribution source device exceeds a threshold value. , Transmitted from the other relay device in response to the relay start request Relay apparatus characterized by receiving the signal data. The relay apparatus according to claim 3, wherein the request transmission unit requests the other relay apparatus to stop transmitting the distribution data. Including a table associating an address in the multicast-capable network with an address in the network incapable of multicasting, and tunneling the network section incapable of multicasting by referring to the table and converting the address. The relay device according to any one of claims 1 to 4, wherein the relay device is characterized in that: A data distribution method for relaying distribution data sent from a distribution source device existing in a multicast-capable network to a device existing in a multicast-capable network by tunneling a network section where multicast is not possible, the distribution Responding to a relay start request transmitted from a relay device that is present in a network other than the network where the data distribution source device is present and has received a relay start response from the distribution source device in response to a relay start request to the distribution source device Then, the distribution data is transmitted to the request source of the relay start request, and the relay start response is transmitted when the load of the distribution source device exceeds a threshold value.

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