JP6861102B2 - Data distribution device and program - Google Patents

Description

The present invention relates to a data distribution device that distributes (transfers) multicast data.

The standard specifications of the multicast communication method are specified in RFC1112. According to this specification, the terminal (receiver) transmits a delivery request message to a router, which is a component of the network, in accordance with IGMP (Internet Group Management Protocol).

A router corresponding to a multicast protocol requests the transmission of a multicast packet from a neighboring router according to a protocol such as PIM-SM. The associated router forwards the multicast packets in sequence. As a result, the multicast data is transmitted to the requesting terminal, and multicast distribution is realized.

A router that supports the multicast protocol forwards multicast packets only to the port on which the terminal that requested the multicast data exists. On the other hand, a packet forwarding device that does not support the multicast protocol, such as a layer 2 switch, forwards (broadcasts) the multicast packet to all ports.

That is, a router that does not support the multicast protocol forwards a multicast packet even to a port on which a terminal that does not request multicast data exists. Therefore, the network bandwidth is wasted.

In order to solve this problem, a method of forwarding a multicast packet as a unicast packet according to the load of the device is disclosed (see, for example, Patent Document 1). Further, a method of delivering multicast data to a multicast network via a unicast network is also disclosed (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2011-217038 Japanese Unexamined Patent Publication No. 2004-172932

The method of Patent Document 1 described above assumes packet transfer of a network layered by a core device and an edge device, and wastes network bandwidth by determining a switch for converting a multicast packet into a unicast packet. Control consumption.

However, in a network in which packet forwarding devices (data distribution devices) that do not support the multicast protocol are irregularly arranged, it is not possible to determine a criterion for determining a switch for converting a multicast packet into a unicast packet. Therefore, the method of Patent Document 1 cannot be applied to such a network.

Further, the method of Patent Document 2 described above assumes one-way communication from a unicast network to a multicast network, and multicasts in a network in which data distribution devices that do not support the multicast protocol are irregularly arranged. Does not consider delivery. Therefore, the method of Patent Document 2 cannot be applied to such a network.

In this way, for a network in which a data distribution device that supports the multicast protocol (multicast-compatible data distribution device) and a data distribution device that does not support multicast (multicast non-support data distribution device) are irregularly arranged, the above-mentioned The methods of Patent Documents 1 and 2 cannot be applied. Therefore, in such a network, there is a problem that wasteful consumption of network bandwidth cannot be suppressed.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to waste network bandwidth in a network in which multicast-compatible data distribution devices and non-multicast-compatible data distribution devices are irregularly arranged. It is an object of the present invention to provide a data distribution device and a program capable of suppressing consumption.

In order to solve the above problem, in the data distribution device of claim 1, the data distribution device corresponding to the multicast protocol and the packet transfer device not supporting the multicast protocol are irregularly arranged, and the downstream device requesting the multicast delivery is requested. A packet forwarding device corresponding to the multicast protocol in a network including a receiving device on the side and a transmitting device on the upstream side that performs the multicast distribution, and is a request source which is an IP address of the receiving device corresponding to the multicast address. When the request list in which the IP address and connection port number are registered and the multicast request packet transmitted from the receiving device are received, the multicast request packet is forwarded to the upstream side or unicast for the multicast request packet. When a packet is transmitted to the downstream side and a multicast packet transmitted from the transmitting device is received, a unicast packet is transmitted to the downstream side, and when a unicast packet is received from the upstream side, the unicast packet is transmitted to the downstream side. A communication unit that transfers to and a multicast packet processing unit that extracts a multicast address from the multicast packet received by the communication unit, sets the multicast address as the source IP address of the multicast packet, and generates a new multicast packet. Then, the multicast address and the requesting source IP address are extracted from the multicast request packet received by the communication unit, and when the multicast address is not registered in the request list, the multicast address, the requesting source IP address, and the said For the multicast request packet processing unit that adds the connection port number of the connection port that received the multicast request packet to the request list and the new multicast packet generated by the multicast packet processing unit, the multicast of the new multicast packet is performed. A multicast / unicast conversion unit that converts the new multicast packet into a unicast packet by reading the request source IP address corresponding to the address from the request list and setting the request source IP address as the destination IP address. A multicast address is extracted from the unicast packet received by the communication unit, and the multicast address is used as the request. If it is not registered in the strike, it includes a unicast packet processing unit that adds the multicast address to the request list, and the communication unit sets the multicast address as the source IP address of the received packet. If it is determined that the packet is the unicast packet, the multicast request packet processing unit receives the multicast request packet by the communication unit, and the multicast address extracted from the multicast request packet is the multicast address. When registered in the request list, the unicast packet received by the communication unit is copied, and the multicast / unicast conversion unit refers to the unicast packet copied by the multicast request packet processing unit. A new unicast packet is generated by reading the request source IP address corresponding to the multicast address of the unicast packet from the request list and setting the request source IP address as the destination IP address. The new unicast packet generated by the multicast / unicast conversion unit is transmitted to the receiving device that has transmitted the multicast request packet.

Further, the data distribution device according to claim 2 is the data distribution device according to claim 1, wherein the multicast request packet processing unit receives the multicast request packet by the communication unit and extracts the multicast request packet from the multicast request packet. When the multicast address is registered in the request list, the new multicast packet generated by the multicast packet processing unit is copied, and the multicast / unicast conversion unit is copied by the multicast request packet processing unit. For the new multicast packet, a new unicast packet is created by reading the request source IP address corresponding to the multicast address of the new multicast packet from the request list and setting the request source IP address as the destination IP address. The communication unit generates and transmits the new unicast packet generated by the multicast / unicast conversion unit to the receiving device that has transmitted the multicast request packet.

Further, in the data distribution device according to claim 3, in the data distribution device according to claim 1 or 2, the counter current value of the number of transmitted unicast packets is further registered corresponding to the connection port number. The counter list and the counter current value corresponding to the predetermined connection port number of the connection port for forwarding the unicast packet are read from the counter list, the counter current value is incremented, and the increment result exceeds the predetermined set value. If not, the predetermined connection port number is selected, and if the increment result exceeds the predetermined set value, the connection port number whose current counter value does not exceed the predetermined set value from the counter list. The communication unit includes a connection port selection unit for selecting the above, and the communication unit transmits the unicast packet from the connection port having the connection port number selected by the connection port selection unit.

Further, the data distribution device according to claim 4 is the data distribution device according to any one of claims 1 to 3, further, the unicast packet transmitted by the communication unit, and then by the communication unit. When the unicast packet received in the above is the same, the unicast packet is provided with a loop detection unit for detecting that the unicast packet has looped and returned.

Further, in the data distribution device of claim 5, the data distribution device corresponding to the multicast protocol and the packet transfer device not supporting the multicast protocol are irregularly arranged, and the receiving device on the downstream side requesting the multicast distribution and the above-mentioned A packet transfer device corresponding to the multicast protocol in a network including an upstream transmission device that performs multicast distribution, the data distribution device is composed of a switch and a controller, and the switch is transmitted from the reception device. When a multicast request packet is received, the multicast request packet is forwarded to the upstream side, or a unicast packet for the multicast request packet is transmitted to the downstream side and the multicast packet transmitted from the transmitting device is received. When a unicast packet is transmitted to the downstream side and a unicast packet is received from the upstream side, the receiver is provided with a communication unit that transfers the unicast packet to the downstream side, and the controller corresponds to the multicast address. The request list in which the request source IP address and the connection port number are registered, and the multicast address are extracted from the multicast packet received by the communication unit, and the multicast address is used as the source IP address of the multicast packet. The multicast address and the request source IP address are extracted from the multicast packet processing unit that generates a new multicast packet and the multicast request packet received by the communication unit, and the multicast address is registered in the request list. If not, the multicast address, the request source IP address, and the connection port number of the connection port that received the multicast request packet are generated by the multicast request packet processing unit that adds the connection port number to the request list and the multicast packet processing unit. For the new multicast packet, the request source IP address corresponding to the multicast address of the new multicast packet is read from the request list, and the request source IP address is set as the destination IP address to obtain the new multicast packet. A multicast / unicast packet that converts the packet into a unicast packet, and the unicast packet received by the communication unit. A unicast packet processing unit that extracts a multicast address from a packet and adds the multicast address to the request list when the multicast address is not registered in the request list is provided, and the communication unit of the switch is provided with a unicast packet processing unit. When it is determined that the multicast address is set in the source IP address of the received packet, it is determined that the packet is the unicast packet, and the multicast request packet processing unit of the controller is determined by the communication unit. When the multicast request packet is received and the multicast address extracted from the multicast request packet is registered in the request list, the unicast packet received by the communication unit is copied and the multicast / The unicast conversion unit reads the request source IP address corresponding to the multicast address of the unicast packet from the request list for the unicast packet copied by the multicast request packet processing unit, and addresses the request source IP address. By setting the IP address, a new unicast packet is generated, and the communication unit of the switch transmits the new unicast packet generated by the multicast / unicast conversion unit to the multicast request packet. The packet is transmitted to the receiving device.

Further, the program of claim 6 is characterized in that the computer functions as the data distribution device according to any one of claims 1 to 5.

As described above, according to the present invention, it is possible to suppress wasteful consumption of network bandwidth in a network in which a multicast-compatible data distribution device and a non-multicast-compatible data distribution device are irregularly arranged.

It is a figure which shows the basic configuration example of the data distribution apparatus (corresponding switch) by embodiment of this invention. This is a configuration example of a first network for explaining the first embodiment. This is a configuration example of a second network for explaining the first embodiment. It is a block diagram which shows the structural example of the corresponding switch of Example 1. FIG. It is a flowchart which shows the processing example of the multicast request packet and the multicast packet by the corresponding switch of Example 1. FIG. It is a flowchart which shows the processing example of the unicast packet by the corresponding switch of Example 1. FIG. It is a figure which supplements the explanation of the flowchart of FIG. 5 and FIG. It is a figure which shows the structure example of the request list. It is a figure which shows the structure of an IP header. It is a block diagram which shows the structural example of the corresponding switch of Example 2. FIG. It is a flowchart which shows the connection port selection processing example by the corresponding switch of Example 2. It is a figure which shows the structural example of the counter list. This is a network configuration example for explaining the second embodiment.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a basic configuration example of a data distribution device (corresponding switch) according to an embodiment of the present invention. The data distribution device 1 is a packet transfer device that realizes SDN (Software Defined Network) and supports a multicast protocol, that is, a multicast-compatible data distribution device.

As shown in FIG. 1, the data distribution device 1 includes a switch 2 and a controller 3. The data distribution device 1 is irregularly arranged together with a packet transfer device that does not support the multicast protocol, that is, a data distribution device that does not support multicast in a network including a transmission device and a reception device (not shown).

When the switch 2 receives the packet, the switch 2 outputs the transfer destination inquiry information including the packet to the controller 3 in order to inquire the transfer destination of the packet to the controller 3, and outputs the information of the transfer port number for transferring the packet from the controller 3. get.

When the controller 3 inputs the forwarding destination inquiry information including the packet from the switch 2, the controller 3 analyzes the packet header according to a predetermined program and identifies the forwarding port based on the source IP address, the destination IP address, etc. included in the packet header. To do. Then, the controller 3 outputs the transfer port number to the switch 2. The switch 2 inputs the forwarding port number from the controller 3, and transfers the received packet from the forwarding port of the input forwarding port number.

The data distribution device 1 composed of the switch 2 and the controller 3 performs the processing of the corresponding switch 11 described later in addition to the processing described above. The data distribution device 1 can be realized by implementing an Openflow compatible switch or the like. Further, the switch 2 and the controller 3 are connected by a LAN, a serial interface, or the like.

[Example 1]
First, Example 1 will be described. When the corresponding switch, which is the data distribution device 1 of the first embodiment, receives the multicast request packet from the receiving device requesting the multicast distribution, the multicast packet that has already been received without forwarding the multicast request packet to the upstream side. Alternatively, it is characterized in that a unicast packet (a unicast packet obtained by converting a multicast packet) is copied and the unicast packet is transmitted to the receiving device.

FIG. 2 is a configuration example of the first network for explaining the first embodiment, and FIG. 3 is a configuration example of the second network for explaining the first embodiment. The first network shown in FIG. 2 includes a corresponding switch 11, a non-corresponding switch 12, and receiving devices 21, 22, and 23. Routes are set for the corresponding switch 11, the non-corresponding switch 12, the corresponding switch 11, the receiving device 21, the non-corresponding switch 12, the receiving device 22, and the non-corresponding switch 12 and the receiving device 23, respectively.

The second network shown in FIG. 3 includes the corresponding switches 11A, 11B, 11C, the non-corresponding switch 12, and the receiving device 24. Routes are set for the corresponding switch 11A and the non-corresponding switch 12, the non-corresponding switch 12 and the corresponding switch 11B, the corresponding switch 11B and the corresponding switch 11C, and the corresponding switch 11B and the receiving device 24, respectively.

FIG. 4 is a block diagram showing a configuration example of the corresponding switch of the first embodiment. The corresponding switch 11 corresponds to the corresponding switch 11 in the network shown in FIG. 2, and corresponds to the corresponding switches 11A to 11C in the network shown in FIG. The corresponding switch 11 includes a communication unit 31, a multicast request packet processing unit 32, a request list 33, a multicast packet processing unit 34, a multicast / unicast conversion unit 35, and a unicast packet processing unit 36.

The corresponding switch 11 is a switch corresponding to the multicast protocol, and corresponds to the data distribution device 1 shown in FIG. In addition, in FIGS. 2 and 3, the non-corresponding switch 12 is a switch which does not correspond to the multicast protocol such as a layer 2 switch.

With reference to FIG. 4, the communication unit 31 of the corresponding switch 11 receives the multicast request packet (Rq) transmitted from the receiving devices 21 to 24 on the downstream side (downstream side of the corresponding switch 11) requesting the multicast delivery. Then, the multicast request packet is output to the multicast request packet processing unit 32. Further, the communication unit 31 inputs the multicast request packet from the multicast request packet processing unit 32 and forwards the multicast request packet to the transmission device 10 on the upstream side.

The communication unit 31 receives the multicast packet (MP) transmitted from the transmission device 10 that performs multicast distribution, and outputs the multicast packet to the multicast packet processing unit 34. Further, the communication unit 31 inputs a unicast packet (UP) from the multicast / unicast conversion unit 35, and transmits the unicast packet to the receiving devices 21 to 24 on the downstream side that requested the multicast distribution.

The communication unit 31 receives the unicast packet from the upstream side and outputs the unicast packet to the unicast packet processing unit 36. Further, the communication unit 31 inputs the unicast packet from the unicast packet processing unit 36, and transfers the unicast packet to the receiving devices 21 to 24 on the downstream side that requested the multicast distribution.

The multicast request packet processing unit 32 inputs a multicast request packet (a multicast request packet transmitted from receiving devices 21 to 24 on the downstream side (downstream side of the corresponding switch 11) requesting multicast delivery) from the communication unit 31. Then, the multicast request packet processing unit 32 uses the multicast address stored in the multicast request packet and the request source IP address (IP address of the receiving devices 21 to 24 that requested the multicast delivery) set in the source IP address. Based on this, the predetermined data is added to the request list 33. The predetermined data will be described later. Further, the multicast request packet processing unit 32 outputs the multicast request packet to the communication unit 31. As a result, the multicast request packet is transferred from the communication unit 31 to the transmission device 10 on the upstream side.

When the multicast request packet processing unit 32 adds predetermined data to the request list 33, if the multicast address stored in the multicast request packet is already stored in the request list 33, the multicast request packet processing unit 32 is a multicast packet or a uni for the multicast request packet. Assuming that the cast packet has already been received, a multicast packet that has already been received (a multicast packet in which a multicast address is set in the source IP address by the multicast packet processing unit 34 described later and stored in memory) or a uni that has already been received. The cast packet (unicast packet stored in the memory by the unicast packet processing unit 36 described later) is copied. Then, the multicast request packet processing unit 32 outputs the multicast packet or the unicast packet to the multicast / unicast conversion unit 35.

As a result, the multicast packet is converted into a unicast packet by the multicast / unicast conversion unit 35. Then, the unicast packet is transmitted to the receiving devices 21 to 24 on the downstream side that requested the multicast distribution without the multicast request packet being transferred to the transmitting device 10 on the upstream side.

FIG. 8 is a diagram showing a configuration example of the request list 33. The request list 33 is composed of a multicast address, a request source IP address, and a connection port number. The multicast address is an IP address representing a plurality of destinations of multicast distribution, and the request source IP address is the IP address of the receiving devices 21 to 24 that requested the multicast distribution. The connection port number is the number of the connection port to which the receiving devices 21 to 24 that requested the multicast delivery are connected, and when the communication unit 31 receives the multicast request packet, the connection port that received the multicast request packet. Indicates the number of.

In the example of FIG. 8, MA1, MA2, ... Are stored as multicast addresses, and for multicast address = MA1, RQ1, RQ2, ... As request source IP addresses, and connection ports corresponding to these. P1, P2, ... Are stored. Further, for the multicast address = MA2, RQ11, RQ12, ... As request source IP addresses, and P2, P2, ... As connection ports corresponding to these are stored.

FIG. 9 is a diagram showing the configuration of the IP header. IP packets such as multicast request packets, multicast packets and unicast packets are composed of an IP header and an IP payload. As shown in FIG. 9, the IP header is composed of data such as "version", "header length" ..., "source IP address", and "destination IP address". The "source IP address" is the IP address of the source terminal to which the IP packet is transmitted, and the "destination IP address" is the IP address of the destination terminal to which the IP packet is transmitted.

For example, referring to FIG. 2, in the multicast request packet transmitted from the receiving device 21, the IP address of the receiving device 21 is set as the “source IP address”, and the IP of the transmitting device 10 is set as the “destination IP address”. The address is set. Further, in the multicast packet transmitted from the transmitting device 10 to the receiving device 21 or the like, the IP address of the transmitting device 10 is set as the "source IP address", and the multicast address is set as the "destination IP address".

Further, in the unicast packet transmitted from the corresponding switch 11 to the receiving device 21, a multicast address is set as the "source IP address" (details will be described later), and the IP of the receiving device 21 is set as the "destination IP address". The address is set. Similarly, a multicast address is set as the "source IP address" for each unicast packet transmitted from the corresponding switch 11 to the receiving devices 22 and 23 via the non-corresponding switch 12 (details will be described later). .. Similarly, the IP addresses of the receiving devices 22 and 23 are set as the "destination IP address", respectively.

Returning to FIG. 4, the multicast packet processing unit 34 inputs a multicast packet (multicast packet transmitted from the transmission device 10) from the communication unit 31. Then, the multicast packet processing unit 34 takes out the multicast address set as the destination IP address of the multicast packet and sets it as the source IP address. The multicast packet processing unit 34 stores the multicast packet in which the multicast address is set as the source IP address in the memory, and outputs the multicast packet to the multicast / unicast conversion unit 35. As a result, the IP address of the transmission device 10 set as the source IP address of the multicast packet is rewritten to the multicast address.

The multicast / unicast conversion unit 35 inputs a copied multicast packet or unicast packet from the multicast request packet processing unit 32, or inputs a multicast packet from the multicast packet processing unit 34. A multicast address is set as the source IP address of the multicast packet and the unicast packet input by the multicast / unicast conversion unit 35.

The multicast / unicast conversion unit 35 collates the request list 33 and identifies the request source IP address that is the destination of the multicast packet or the unicast packet based on the multicast address. Then, the multicast / unicast conversion unit 35 converts the multicast packet into a unicast packet by setting the request source IP address as the destination IP address of the multicast packet. Alternatively, the multicast / unicast conversion unit 35 generates a new unicast packet by setting the request source IP address as the destination IP address of the unicast packet. The multicast / unicast conversion unit 35 outputs a unicast packet to the communication unit 31.

As a result, when the corresponding switch 11 receives the multicast packet, the multicast packet is converted into a unicast packet and transmitted without being transmitted to the receiving devices 21 to 24 on the downstream side that requested the multicast delivery. Then, referring to FIGS. 2 and 3, the downstream non-corresponding switch 12 receives the unicast packet instead of receiving the multicast packet from the corresponding switch 11. That is, the multicast packet is converted into a unicast packet by the corresponding switch 11 arranged in front of the non-corresponding switch 12.

Therefore, the non-compliant switch 12 does not need to forward (broadcast) the multicast packet to all the ports, and does not waste the network bandwidth.

Further, when the corresponding switch 11 receives the multicast request packet, the unicast packet is transmitted to the receiving devices 21 to 24 on the downstream side without transmitting the multicast request packet to the transmitting device 10 on the upstream side. Therefore, the network bandwidth is not wasted.

Returning to FIG. 4, when the unicast packet processing unit 36 inputs the unicast packet from the communication unit 31 and the multicast address set as the source IP address of the unicast packet is not registered in the request list 33, The multicast address is added to the request list 33. Then, the unicast packet processing unit 36 stores the unicast packet in the memory and outputs it to the communication unit 31. As a result, the unicast packet is transferred from the communication unit 31 to the receiving devices 21 to 24 on the downstream side that requested the multicast distribution.

(Multicast request packet and multicast packet processing example)
Next, the processing of the multicast request packet processing unit 32, the multicast packet processing unit 34, and the multicast / unicast conversion unit 35 of the corresponding switch 11 shown in FIG. 4 will be described.

FIG. 5 is a flowchart showing an example of processing a multicast request packet and a multicast packet by the corresponding switch 11 of the first embodiment, and FIG. 7 is a diagram supplementing the description of the flowchart of FIG. 5 and FIG. 6 described later. In FIG. 5, the source address indicates the source IP address, the destination address indicates the destination IP address, the request source address indicates the request source IP address, and the connection port indicates the connection port number, and the description of the IP and the number is omitted. is there. The same applies to FIGS. 6 and 11 described later.

The communication unit 31 of the corresponding switch 11 receives and waits for the multicast request packet transmitted from the receiving devices 21 to 24 (step S501). The receiving devices 21 to 24 transmit the multicast request packet, and the communication unit 31 of the corresponding switch 11 receives the multicast request packet. Then, the multicast request packet processing unit 32 extracts the multicast address from the multicast request packet and also extracts the request source IP address set in the source IP address (step S502).

By collating the request list 33, the multicast request packet processing unit 32 determines whether or not the multicast address extracted from the multicast request packet is registered in the request list 33 (step S503).

When the multicast request packet processing unit 32 determines in step S503 that the multicast address is not registered in the request list 33 (step S503: no multicast address), the multicast request packet processing unit 32 requests the multicast address, the request source IP address, and the connection port number. Add to list 33 (step S504). As described above, the connection port number is the number of the connection port on which the communication unit 31 has received the multicast request packet. As a result, a new multicast address, request source IP address, and connection port number are registered in the request list 33.

The communication unit 31 forwards the received multicast request packet to the transmission destination device 10 (step S505).

With reference to FIG. 7 (1), the corresponding switch 11 performs the processes of steps S501 to S505 described above. The corresponding switch 11 receives the multicast request packet from, for example, the receiving device 21 (see FIG. 2). Then, the corresponding switch 11 displays the new multicast address, the request source IP address (IP address of the receiving device 21), and the connection port number (the number of the connection port that received the multicast request packet from the receiving device 21) in the request list 33. To add. The corresponding switch 11 forwards the multicast request packet.

Returning to FIG. 5, the communication unit 31 waits for receiving the multicast packet transmitted from the transmission device 10 (step S506). The transmitting device 10 transmits the multicast packet, and the communication unit 31 of the corresponding switch 11 receives the multicast packet. Then, the multicast packet processing unit 34 extracts the multicast address from the destination IP address of the multicast packet (step S507).

The multicast packet processing unit 34 sets the multicast address in the source IP address of the multicast packet (step S508). As a result, the IP address of the transmitting device 10 set as the source IP address is changed to the multicast address, and the corresponding switches 11B, 11C, etc. on the downstream side (when the corresponding switch 11 is the corresponding switch 11A in FIG. 3). Can determine that the received packet is a unicast packet (a unicast packet obtained by converting a multicast packet), which will be described later, based on the multicast address set in the source IP address.

The multicast packet processing unit 34 stores the multicast packet in which the multicast address is set as the source IP address in the memory.

The multicast / unicast conversion unit 35 reads the first registered request source IP address and connection port number corresponding to the multicast address from the request list 33 (step S509). The first registered request source IP address and connection port number are the data when the multicast address is newly registered in step S504.

The multicast / unicast conversion unit 35 sets the request source IP address (the request source IP address read in step S509 or the request source IP address added in step S510 described later) as the destination IP address of the multicast packet. , Converts the multicast packet into a unicast packet (step S512). As a result, the multicast address set in the destination IP address is changed to the request source IP address, and a unicast packet is generated.

The communication unit 31 transmits the unicast packet from the connection port of the connection port number (the connection port number read in step S509 or the connection port number added in step S510 described later) (step S513).

With reference to FIG. 7 (2), the corresponding switch 11 performs the processes of step S506 to step S509, step S512, and step S513 described above. The corresponding switch 11 receives the multicast packet from, for example, the transmitting device 10 (see FIG. 2), and reads out the receiving source IP address and the connection port number corresponding to the multicast address from the request list 33. Then, the corresponding switch 11 converts the multicast packet into a unicast packet and transmits the unicast packet to, for example, the receiving device 21.

Returning to FIG. 5, on the other hand, when the multicast request packet processing unit 32 determines in step S503 that the multicast address is registered in the request list 33 (step S503: with the multicast address), the request source of the multicast request packet. The IP address and the connection port number are added to the request list 33 in correspondence with the already registered multicast address (step S510). As a result, the request source IP address and the connection port number are registered in the request list 33 corresponding to the already registered multicast addresses.

The multicast request packet processing unit 32 is stored in the memory of the already received multicast packet (when the multicast address is set as the source IP address in step S508) corresponding to the multicast address stored in the multicast request packet. (Multicast packet) is copied (step S511). Alternatively, the multicast request packet processing unit 32 copies the already received unicast packet (unicast packet stored in the memory in the process of FIG. 6 described later) corresponding to the multicast address stored in the multicast request packet. To do.

In step S512, the multicast / unicast conversion unit 35 adds a request source IP address (request source IP address added in step S510) to the destination IP address of the multicast packet (or unicast packet) copied in step S511. ) Is set to convert the multicast packet to a unicast packet (generate a new unicast packet). Then, in step S513, the communication unit 31 transmits the unicast packet from the connection port of the connection port number (the connection port number added in step S510).

With reference to FIG. 7 (3), the corresponding switch 11 performs the processes of steps S501 to S503 and steps S510 to S513 described above. The corresponding switch 11 receives, for example, a multicast request packet from the receiving device 22 (see FIG. 2), and corresponds to the multicast address already registered in the request list 33, and corresponds to the request source IP address (IP of the receiving device 22). The address) and the connection port number (the number of the connection port that received the multicast request packet from the receiving device 22) are added.

The corresponding switch 11 copies the already received multicast packet corresponding to the multicast address stored in the multicast request packet. The corresponding switch 11 converts the multicast packet into a unicast packet and transmits the unicast packet to the receiving device 22. An example of copying a unicast packet will be described later.

Next, a processing example shown in FIG. 5 will be described with reference to FIG. First, it is assumed that the receiving device 21 requests multicast distribution. The receiving device 21 transmits the multicast request packet to the transmitting device 10 (step S201). The corresponding switch 11 receives the multicast request packet, adds the multicast address and the like to the request list 33, and forwards the multicast request packet to the transmitting device 10 (step S202).

The transmission device 10 transmits a multicast packet (step S203). The corresponding switch 11 receives the multicast packet, converts the multicast packet into a unicast packet with reference to the request list 33, and transmits the unicast packet to the receiving device 21 (step S204).

Next, it is assumed that the receiving device 22 requests the same multicast distribution as described above. The receiving device 22 transmits the multicast request packet to the transmitting device 10 (step S205). The non-compliant switch 12 receives the multicast request packet and forwards the multicast request packet (step S206).

The corresponding switch 11 receives the multicast request packet, determines that the same multicast address is registered in the request list 33, and adds the receiving source IP address and the like corresponding to the multicast address. Then, the corresponding switch 11 determines that the multicast packet corresponding to the multicast request packet has already been received, copies the already received multicast packet, converts the copied multicast packet into a unicast packet, and unicast packet. Is transmitted to the receiving device 22 (step S207).

The non-compliant switch 12 receives the unicast packet and forwards the unicast packet to the receiving device 22 (step S208).

Next, it is assumed that the receiving device 23 requests the same multicast distribution as described above. The processing of the receiving device 23, the non-corresponding switch 12, and the corresponding switch 11 is the same as in the case of the receiving device 22 (steps S209 to S212).

Here, the unicast packet transmitted from the corresponding switch 11 to the non-corresponding switch 12 is a packet addressed to the receiving device 22 in which the IP address of the receiving device 22 is set as the destination IP address, and a packet addressed to the receiving device 22 in which the destination IP address is the receiving device 23. It is a packet addressed to the receiving device 23 for which the IP address is set, and two unicast packets are transmitted from the corresponding switch 11 to the non-corresponding switch 12.

The IP address of the receiving device 22 or the receiving device 23 is set as the destination IP address of these unicast packets, and the multicast address is not set. Therefore, the non-corresponding switch 12 can specify a specific transfer destination, and the broadcast does not occur.

(Example of unicast packet processing)
Next, the processing of the unicast packet processing unit 36 of the corresponding switch 11 shown in FIG. 4 will be described. FIG. 6 is a flowchart showing an example of processing a unicast packet by the corresponding switch 11 of the first embodiment.

The communication unit 31 of the corresponding switch 11 receives and waits for receiving a unicast packet (a unicast packet in which a multicast address is set in the source IP address) transmitted from the corresponding switch on the upstream side (step S601). The communication unit 31 determines whether or not a multicast address is set for the source IP address of the received packet. When the communication unit 31 determines that the multicast address is set for the source IP address, it determines that the received packet is a unicast packet.

The corresponding switch on the upstream side transmits the unicast packet, and the communication unit 31 of the corresponding switch 11 receives the unicast packet. Then, the unicast packet processing unit 36 extracts the multicast address set as the source IP address of the unicast packet (step S602). At this time, the unicast packet processing unit 36 stores the unicast packet in the memory.

By collating the request list 33, the unicast packet processing unit 36 determines whether or not the multicast address extracted from the unicast packet is registered in the request list 33 (step S603).

When the unicast packet processing unit 36 determines in step S603 that the multicast address is not registered in the request list 33 (step S603: no multicast address), the unicast packet processing unit 36 adds the multicast address to the request list 33 (step S604). As a result, a new multicast address is registered in the request list 33.

On the other hand, when the unicast packet processing unit 36 determines in step S603 that the multicast address is registered in the request list 33 (step S603: there is a multicast address), the unicast packet processing unit 36 proceeds to step S605.

The communication unit 31 shifts from step S604 or step S603 (with a multicast address) and transfers the received unicast packet (step S605).

With reference to FIG. 7 (4), the corresponding switch 11 performs the processes of steps S601 to S605 described above. The corresponding switch 11 receives the unicast packet from the corresponding switch on the upstream side, and when the multicast address set as the source IP address of the unicast packet is not registered in the request list 33, the corresponding multicast address is added. Forward unicast packets.

As described above, when the multicast address set as the source IP address of the unicast packet received from the upstream side is not registered in the request list 33, the unicast packet processing unit 36 puts the multicast address in the request list 33. sign up.

After that, when the same multicast distribution request is received from the receiving devices 21 to 24 and the corresponding switch 11 receives the multicast request packet, the processes of steps S501 to S503 and steps S510 to S513 shown in FIG. 5 are performed.

Specifically, when the communication unit 31 receives the multicast request packet in step S501, the multicast request packet processing unit 32 extracts the multicast address and the request source IP address from the multicast request packet in step S502. In step S503 and step S510, the multicast request packet processing unit 32 adds the request source IP address and the connection port number to the request list 33 in response to the multicast address.

The multicast request packet processing unit 32 has already received the unicast packet in step S511 (the unicast packet stored in the memory when the unicast packet processing unit 36 extracts the multicast address from the unicast packet in step S602). To copy.

In step S512, the multicast / unicast conversion unit 35 sets the request source IP address (request source IP address added in step S510) as the destination IP address of the unicast packet. In step S513, the communication unit 31 transmits the unicast packet from the connection port of the connection port number (the connection port number added in step S510).

Next, a processing example shown in FIG. 6 will be described with reference to FIG. First, the corresponding switch 11A that has received the multicast packet for the multicast request packet from the receiving device (not shown) converts the multicast packet into a unicast packet. Then, the corresponding switch 11A transmits a unicast packet (UP) to the corresponding switch 11B via the non-corresponding switch 12 (step S301, step S302).

The corresponding switch 11B receives the unicast packet, registers the multicast address set as the source IP address of the unicast packet in the request list 33, and transfers the unicast packet to the corresponding switch 11C (step S303). Further, the corresponding switch 11C transfers the unicast packet received from the corresponding switch 11B to a receiving device (not shown) (step S304).

The multicast address set as the source IP address of the unicast packet is added to the request list 33 of the corresponding switch 11B, and the unicast packet is stored in the memory. Then, it is assumed that the receiving device 24 requests multicast distribution in which the same multicast address is stored.

The receiving device 24 transmits the multicast request packet, and the corresponding switch 11B receives the multicast request packet (step S305). Corresponding switch 11B determines that the same multicast address is registered in the request list 33, and adds a receiving source IP address or the like corresponding to the multicast address. Then, the corresponding switch 11B reads a unicast packet for the multicast request packet (a unicast packet in which the same multicast address as the multicast request packet is stored) from the memory. The corresponding switch 11B copies the unicast packet and transmits the unicast packet to the receiving device 24 (step S306).

In this way, since the corresponding switch 11B has already received the unicast packet, it forwards the multicast request packet received from the receiving device 24 to the upstream side, and the multicast packet or the unicast packet for the multicast request packet from the upstream side. It is not necessary to wait for reception, and a unicast packet for a multicast request packet can be transmitted to the receiving device 24. Therefore, since the multicast request packet transmitted to the upstream side and the multicast packet or the unicast packet received from the upstream side are not required, it is possible to suppress wasteful consumption of the network bandwidth.

As described above, according to the corresponding switch 11 of the first embodiment shown in FIG. 4, the multicast request packet processing unit 32 multicasts based on the multicast address and the request source IP address stored in the received multicast request packet. The address, request source IP address and connection port number are added to the request list 33.

The multicast packet processing unit 34 takes out the multicast address of the multicast packet received from the transmission device 10 and sets it as the source IP address. Then, the multicast / unicast conversion unit 35 converts the multicast packet into a unicast packet, and the communication unit 31 transmits the unicast packet to the receiving devices 21 to 24.

After that, when the corresponding switch 11 receives the multicast request packet including the same multicast address, the multicast request packet processing unit 32 determines that the multicast address of the received multicast request packet is already stored in the request list 33, and has already determined that the multicast address is already stored in the request list 33. Copy the received multicast packet (multicast packet whose multicast address is set to the source IP address). Then, the multicast / unicast conversion unit 35 converts the multicast packet into a unicast packet, and the communication unit 31 transmits the unicast packet to the receiving devices 21 to 24.

As a result, the multicast request packet is transmitted to the downstream receiving devices 21 to 24 for which the unicast packet has requested the multicast delivery, without being forwarded to the upstream transmitting device 10. Therefore, it is possible to suppress wasteful consumption of network bandwidth.

When the communication unit 31 determines that the multicast address is set for the source IP address of the received packet, it determines that the received packet is a unicast packet. The unicast packet processing unit 36 adds the multicast address to the request list 33 based on the multicast address set in the source IP address of the received unicast packet.

After that, when the corresponding switch 11 receives the multicast request packet including the same multicast address, the multicast address is already stored in the request list 33. The multicast request packet processing unit 32 copies the unicast packet that has already been received. The multicast / unicast conversion unit 35 sets the request source IP address of the multicast request packet as the destination IP address, generates a new unicast packet, and the communication unit 31 sends the unicast packet to the receiving devices 21 to 24. Send.

As a result, the multicast request packet is transmitted to the receiving devices 21 to 24 without being transferred to the transmitting device 10. Therefore, it is possible to suppress wasteful consumption of network bandwidth.

In this way, referring to FIG. 3, the corresponding switch 11A on the upstream side sets the multicast address in the source IP of the multicast packet, generates a unicast packet, and transmits the unicast packet, so that the corresponding switch 11B on the downstream side Can determine that the packet is a unicast packet (a unicast packet obtained by converting a multicast packet) based on the source IP of the received packet.

Further, the corresponding switch 11B stores the unicast packet in the memory in preparation for the subsequent reception of the multicast request packet, and when the multicast request packet is received, the corresponding switch 11B does not forward the multicast request packet to the upstream side. The unicast packet stored in the memory can be used to transmit the unicast packet to the receiving devices 21 to 24.

In particular, in a network in which a plurality of corresponding switches 11A, 11B, etc. are arranged between the transmission device 10 and the receiving device 24, the corresponding switch 11B arranged closest to the receiving device 24 is the receiving device 24. First receives a multicast request packet from. Then, the corresponding switch 11B can copy the unicast packet and transmit it to the receiving device 24 without forwarding the multicast request packet to the upstream side.

Therefore, in a network in which a plurality of multicast-compatible data distribution devices (corresponding switch 11) and a plurality of non-multicast-compatible data distribution devices (non-supporting switch 12) are irregularly arranged, receiving devices 21 to request multicast distribution. Unicast packets can be transferred only to the route to 24, and wasteful consumption of network bandwidth can be suppressed.

[Example 2]
Next, Example 2 will be described. The corresponding switch of the second embodiment counts the number of unicast packets when a plurality of routes exist between the receiving device requesting the multicast delivery and the transmitting device performing the multicast delivery, and based on the count value, the corresponding switch counts the number of unicast packets. It is characterized in that a free connection port is selected and a unicast packet is forwarded from the selected connection port.

FIG. 10 is a block diagram showing a configuration example of the corresponding switch of the second embodiment. The corresponding switch 11 includes a communication unit 31, a multicast request packet processing unit 32, a request list 33, a multicast packet processing unit 34, a multicast / unicast conversion unit 35, a unicast packet processing unit 36, a connection port selection unit 37, and a counter list. It has 38.

Comparing the corresponding switch 11 of the first embodiment shown in FIG. 4 with the corresponding switch 11 of the second embodiment shown in FIG. 10, both corresponding switches 11 include a communication unit 31, a multicast request packet processing unit 32, and a request list 33. It is common in that it includes a multicast packet processing unit 34, a multicast / unicast conversion unit 35, and a unicast packet processing unit 36. On the other hand, the corresponding switch 11 of the second embodiment is different in that the corresponding switch 11 of the second embodiment further includes the connection port selection unit 37 and the counter list 38 in addition to the configuration of the first embodiment. In FIG. 10, the parts common to FIG. 4 are designated by the same reference numerals as those in FIG. 4, and detailed description thereof will be omitted.

The communication unit 31 receives the unicast packet from the upstream side, outputs the unicast packet to the unicast packet processing unit 36, and outputs the unicast packet to the connection port selection unit 37. Then, the communication unit 31 forwards the unicast packet from the connection port of the connection port number selected by the connection port selection unit 37.

The connection port selection unit 37 inputs a unicast packet from the communication unit 31, and is a counter current value for the connection port to which the unicast packet is to be transferred (the number of unicast packets transferred by the corresponding switch 11 from the connection port). Is read from the counter list 38. Then, the connection port selection unit 37 increments the current value of the counter, and if the increment result does not exceed a predetermined set value, the connection port selection unit 37 selects the connection port number to be transferred.
On the other hand, when the increment result exceeds a predetermined set value, the connection port selection unit 37 searches for a vacant connection port number and selects the searched connection port number. The connection port selection unit 37 reads the counter current value of the selected connection port number from the counter list 38, increments it, and stores it. Then, the communication unit 31 forwards the unicast packet from the connection port of the connection port number selected by the connection port selection unit 37.

FIG. 12 is a diagram showing a configuration example of the counter list 38. In the counter list 38, the number of unicast packets transferred from the connection port of the connection port number (counter current value) and the setting value (counter setting value) that sets the upper limit thereof are stored for each connection port number. .. Specifically, the counter list 38 is composed of a connection port number, a multicast address, a request source IP address, a counter set value, and a counter current value. As the counter set value, a preset value is used for each connection port number, and for example, the number of unicast packets that can be transmitted at the same time is set based on the bandwidth of the route connected to the connection port.

In the example of FIG. 12, P1, P2, ... Are stored as connection port numbers. For the connection port number = P1, the multicast address = MA1 and the request source IP address = RQ1, the multicast address = MA1, the request source IP address = RQ2, ..., And the counter set value = C1 and the counter current value = C2 are stored. Has been done. Further, for the connection port number = P2, the multicast address = MA1 and the request source IP address = RQ1, the multicast address = MA1 and the request source IP address = RQ2, ..., And the counter set value = C3 and the counter current value = C4. Is stored.

The counter list 38 shown in FIG. 12 shows that the number of unicast packets transferred from the connection port with the connection port number = P1 (counter current value) is C2, and the counter set value is C1. Further, the counter list 38 shows that the number of unicast packets transferred from the connection port of the connection port number = P2 (counter current value) is C4, and the counter set value is C3.

(Example of connection port selection process)
Next, the processing of the connection port selection unit 37 of the corresponding switch 11 shown in FIG. 10 will be described. FIG. 11 is a flowchart showing an example of connection port selection processing by the corresponding switch 11 of the second embodiment.

The communication unit 31 of the corresponding switch 11 waits for receiving the unicast packet transmitted from the corresponding switch on the upstream side (step S1101).

The corresponding switch on the upstream side transmits the unicast packet, and the communication unit 31 of the corresponding switch 11 receives the unicast packet. Then, the connection port selection unit 37 extracts the multicast address set in the source IP address of the unicast packet and also extracts the request source IP address set in the destination IP address (step S1102).

By collating the counter list 38, the connection port selection unit 37 determines whether or not the multicast address extracted from the unicast packet is registered in the counter list 38 (step S1103).

When the connection port selection unit 37 determines in step S1103 that the multicast address is not registered in the counter list 38 (step S1103: no multicast address), the multicast address and the request source correspond to all the connection port numbers. The IP address is added to the counter list 38 (step S1104). As a result, new multicast addresses and requesting source IP addresses are registered in the counter list 38 for all connection port numbers.

The connection port selection unit 37 proceeds from step S1104, reads the counter current value corresponding to the connection port number of the connection port to be used from the counter list 38, and increments the counter current value (step S1107).

Here, as the connection port number of the connection port to be used, the connection port number of the preset default route is used. After that, when a new connection port is selected by the determination in step S1110 described later, the connection port number of the latest selected connection port is used.

On the other hand, when the connection port selection unit 37 determines in step S1103 that the multicast address is registered in the counter list 38 (step S1103: there is a multicast address), the request source IP address corresponding to the multicast address is the counter list 38. It is determined whether or not it is registered in (step S1105).

When the connection port selection unit 37 determines in step S1105 that the request source IP address corresponding to the multicast address is not registered in the counter list 38 (step S1105: none), the request source IP address corresponds to the multicast address. Is added to the counter list 38 (step S1106). As a result, a new request source IP address is registered in the counter list 38 corresponding to the multicast address for all the connection port numbers.

On the other hand, when the connection port selection unit 37 determines in step S1105 that the request source IP address corresponding to the multicast address is registered in the counter list 38 (step S1105: Yes), the connection port selection unit 37 proceeds to step S1107.

The connection port selection unit 37 shifts from step S1106 or step S1105 (with), and in step S1107, reads the counter current value corresponding to the connection port number of the connection port to be used from the counter list 38, and reads the counter current value. Is incremented.

The connection port selection unit 37 proceeds from step S1107 and reads the counter set value corresponding to the connection port number of the connection port to be used from the counter list 38. Then, the connection port selection unit 37 determines whether or not the increment result exceeds the counter set value (step S1108).

When the connection port selection unit 37 determines in step S1108 that the increment result does not exceed the counter set value (step S1108: N), the connection port number of the connection port to be used is used as the connection port number actually used. select. The communication unit 31 forwards the unicast packet from the connection port of the connection port number selected by the connection port selection unit 37, and the connection port selection unit 37 counter list the counter current value corresponding to the selected connection port number. It is read from 38 and incremented, and the counter current value of the increment result is stored in the counter list 38 (step S1109).

On the other hand, when the connection port selection unit 37 determines in step S1108 that the increment result exceeds the counter set value (step S1108: Y), the connection port selection unit 37 determines whether or not another connection port is available (step S1110). ). Specifically, the connection port selection unit 37 reads the counter set value and the counter current value for the connection port number other than the connection port number of the connection port to be used from the counter list 38. Then, the connection port selection unit 37 determines whether or not there is a connection port number whose current counter value does not exceed the counter set value.

In step S1110, the connection port selection unit 37 determines that there is no other connection port available (step S1110: none), that is, there is no connection port number whose current counter value does not exceed the counter set value. If (when it is determined that the current counter value exceeds the counter set value for all other connection ports), it is determined that there is no connection port to select.

In this case, since there is no route for transferring the unicast packet, the communication unit 31 does not transfer the unicast packet (step S1111). As a result, the packet transfer is terminated by the corresponding switch 11.

On the other hand, when the connection port selection unit 37 determines in step S1110 that another connection port is available (step S1110: Yes), that is, when there is a connection port number whose current counter value does not exceed the counter set value. If it is determined, one connection port number is selected according to a preset priority (priority for each connection port number). The communication unit 31 forwards the unicast packet from the connection port of the connection port number selected by the connection port selection unit 37, and the connection port selection unit 37 counter list the counter current value corresponding to the selected connection port number. It is read from 38 and incremented, and the counter current value of the increment result is stored in the counter list 38 (step S1112).

The connection port selection unit 37 may count the bit rate of the unicast packet instead of counting the current value of the counter, which is the number of unicast packets transferred by the corresponding switch 11.

FIG. 13 is a configuration example of a network for explaining the second embodiment. Hereinafter, the processing example shown in FIG. 11 will be described with reference to FIG. The network shown in FIG. 13 includes corresponding switches 13 to 16 and receiving devices 41 to 45.

The path A from the corresponding switch 13 to the corresponding switch 14 is set, and the counter set value of the connection port of the path A in the corresponding switch 13 is set to 3. The path B from the corresponding switch 13 to the corresponding switch 15 is set, and the counter set value of the connection port of the path B in the corresponding switch 13 is set to 3.

The path C from the corresponding switch 14 to the corresponding switch 16 is set, and the counter set value of the connection port of the path C in the corresponding switch 14 is set to 1. Further, the path D from the corresponding switch 15 to the corresponding switch 16 is set, and the counter set value of the connection port of the path D in the corresponding switch 15 is set to 1. The path E from the corresponding switch 15 to the corresponding switch 14 is set, and the counter set value of the path E in the corresponding switch 15 is set to 1.

First, the receiving device 41 transmits the multicast request packet to the transmitting device 51, and the corresponding switch 13 transfers the unicast packet from the connection port of the route A which is the default route to the corresponding switch 14 according to the first embodiment, and the corresponding switch 14 Transfers the unicast packet from the connection port of the route C to the corresponding switch 16, and the corresponding switch 16 transfers the unicast packet to the receiving device 41. In this case, in the corresponding switch 13, the counter current value of the connection port of the path A is 1, which is smaller than the counter set value 3, and in the corresponding switch 14, the counter current value of the connection port of the path C is 1, and the counter. It is the same as the setting value 1.

Further, the receiving devices 42 and 43 transmit the multicast request packet to the transmitting devices 52 and 53, respectively, the corresponding switch 13 transfers the unicast packet from the connection port of the route A to the corresponding switch 14, and the corresponding switch 14 unicasts. It is assumed that the cast packet is transferred to the receiving devices 42 and 43. In this case, in the corresponding switch 13, the counter current value of the connection port of the path A is 3, which is the same as the counter set value 3.

Here, it is assumed that the receiving device 44 transmits the multicast request packet to the transmitting device 54. Then, the corresponding switch 13 determines that the counter current value 4 exceeds the counter set value 3 because the result of incrementing the counter current value of the connection port of the route A is 4 for the unicast packet for the multicast request packet. judge. Then, the corresponding switch 13 selects the connection port of the route B as a free connection port, and transmits the unicast packet from the connection port of the route B to the corresponding switch 15. In this case, in the corresponding switch 13, the counter current value of the connection port of the path B is 1, which is smaller than the counter set value 3.

The corresponding switch 15 receives the unicast packet from the corresponding switch 13, and transfers the unicast packet from the connection port of the route D, which is the default route, to the corresponding switch 16. Then, the corresponding switch 16 forwards the unicast packet to the receiving device 41. In this case, in the corresponding switch 15, the counter current value of the connection port of the path D is 1, which is the same as the counter set value 1.

Then, it is assumed that the receiving device 45 transmits the multicast request packet to the transmitting device 55. Then, the corresponding switch 13 selects the connection port of the route B for the unicast packet for the multicast request packet, and transmits the unicast packet from the connection port of the route B to the corresponding switch 15. In this case, in the corresponding switch 13, the counter current value of the connection port of the path B is 2, which is smaller than the counter set value 3.

The corresponding switch 15 receives the unicast packet from the corresponding switch 13, and the result of incrementing the counter current value of the connection port of the route D is 2, so that the counter current value 2 exceeds the counter set value 1. judge. Then, the corresponding switch 15 selects the connection port of the route E as a free connection port, and transmits the unicast packet from the connection port of the route E to the corresponding switch 14. In this case, in the corresponding switch 15, the counter current value of the connection port of the route E is 1, which is the same as the counter set value 1.

The corresponding switch 14 receives the unicast packet from the corresponding switch 15, and the result of incrementing the counter current value of the connection port of the route C is 2, so that the counter current value 2 exceeds the counter set value 1. judge. Then, the corresponding switch 14 determines that there is no free connection port, and ends the transfer of the unicast packet. The unicast packet does not reach the receiving device 45 that requested the unicast distribution.

When the corresponding switch 14 determines that there is no free connection port, the corresponding switch 14 may transmit a transmission stop request to the transmitting device 55 and transmit non-transmissible information to the receiving device 45.

As described above, according to the corresponding switch 11 of the second embodiment shown in FIG. 10, the connection port selection unit 37 counts the number of unicast packets as the counter current value for the connection port that transfers the unicast packets. , The free connection port is selected as the connection port that actually forwards the unicast packet based on the current value of the counter and the set value of the counter.

As a result, when the route to which the unicast packet is to be forwarded is congested, the connection port of another route can be selected, and multicast distribution that was originally interrupted by congestion can be continued. it can. Therefore, since the unicast packet is forwarded to a non-congested route, in addition to the effect of the first embodiment, the network bandwidth can be effectively utilized, and smooth and stable multicast distribution can be realized. ..

[Modification of Example 2]
Next, a modified example of the second embodiment will be described. A modification of the second embodiment detects in the second embodiment that the transmitted unicast packet loops back when there is no concept of upstream and downstream in the multicast distribution route, and the unicast packet is transmitted. This is an example of stopping the transfer.

The corresponding switch 11 of the modified example of the second embodiment further includes a loop detection unit in addition to the configuration shown in FIG. The communication unit 31 outputs the received unicast packet to the unicast packet processing unit 36 and the connection port selection unit 37, and also outputs the received unicast packet to the loop detection unit.

The loop detection unit inputs a unicast packet from the communication unit 31, and determines whether or not the input unicast packet is a unicast packet that has already been transmitted (transferred) by the communication unit 31. Specifically, the loop detection unit stores the unicast packet transmitted by the communication unit 31 in the memory, and the unicast packet input from the communication unit 31 is the same as the unicast packet stored in the memory. Judge whether or not.

When the loop detection unit determines that the unicast packet input from the communication unit 31 is a unicast packet that has already been transmitted, the unicast packet transmitted from one connection port loops and returns to another connection port. Detect that. Then, when the loop detection unit detects the loop of the unicast packet, the communication unit 31 ends the transfer of the unicast packet. On the other hand, the communication unit 31 transfers the unicast packet when the loop detection unit does not detect the loop of the unicast packet.

In the network shown in FIG. 13, it is assumed that there is no concept of upstream and downstream in the multicast distribution route, and for example, the route F (not shown) from the corresponding switch 14 to the corresponding switch 13 is set.

The corresponding switch 14 receives the unicast packet for the multicast distribution request from the receiving device 45 to the transmitting device 55 from the corresponding switch 15, selects the connection port of the route F as a free connection port, and sets the unicast packet as the route F. It transmits to the corresponding switch 13 from the connection port of.

The corresponding switch 13 receives the unicast packet from the corresponding switch 14, determines that the unicast packet is an already transmitted unicast packet, and the transmitted unicast packet loops from the connection port of the route B. It detects that it has returned to the connection port of route F. Then, the corresponding switch 13 ends the transfer of the unicast packet. The unicast packet does not reach the receiving device 45 that requested the unicast distribution.

When the corresponding switch 13 detects the loop of the unicast packet, the transmission stop request may be transmitted to the transmission device 55, and the transmission impossible information may be transmitted to the reception device 45.

As described above, according to the modified example of the second embodiment, in addition to the effect of the second embodiment, the loop state of the unicast packet can be eliminated, and the wasteful consumption of the network bandwidth can be further suppressed. Become.

Although the present invention has been described above with reference to the modifications of Examples 1 and 2 and Example 2, the present invention is not limited to the above Examples 1 and 2, and is not deviating from the technical idea. It can be deformed in various ways. For example, in the first and second embodiments, the multicast packet processing unit 34 of the corresponding switch 11 takes out the multicast address set as the destination IP address for the multicast packet transmitted from the transmission device 10, and uses this as the source IP address. I set it to. On the other hand, the transmitting device 10 may perform this process before transmitting the multicast packet to transmit the multicast packet whose multicast address is set to the source IP address.

Further, the corresponding switch 11 of the first and second embodiments corresponds to the data distribution device 1 shown in FIG. 1 as described above. Therefore, the processing of the corresponding switch 11 is realized by the switch 2 and the controller 3 constituting the data distribution device 1.

For example, the switch 2 of the data distribution device 1 performs transmission / reception processing of multicast request packets, multicast packets, and unicast packets, and the controller 3 manages the request list 33 and the counter list 38.

Specifically, in the processing example shown in FIG. 5, the switch 2 performs the processing of step S501, step S505, step S506, and step S513. The controller 3 performs the processes of steps S502 to S504 and steps S507 to S512.

Further, in the processing example shown in FIG. 6, the switch 2 performs the processing of steps S601 and S605, and the controller 3 performs the processing of steps S602 to S604. Further, in the processing example shown in FIG. 11, the switch 2 performs step S1101, step S1109 (transfer processing), step S1111, and step S1112 (transfer processing). The controller 3 performs steps S1102 to step S1108, step S1109 (storage process), step S1110, and step S1112 (storage process). In this case, the controller 3 includes the request list 33 in the first embodiment, and the request list 33 and the counter list 38 in the second embodiment.

Here, in a network including a plurality of compatible switches 11, the plurality of compatible switches 11 include a plurality of switches 2 corresponding to each of the plurality of compatible switches 11 and a controller 3 that collectively manages the plurality of switches 2. It may be configured to include. In this case, the plurality of corresponding switches 11 may be divided into a plurality of groups, and the controller 3 may be provided for each group.

As the hardware configuration of the corresponding switch 11 in the modified examples of Examples 1 and 2 and Example 2 of the present invention, a normal computer can be used. The corresponding switch 11 is composed of a computer including a volatile storage medium such as a CPU and RAM, a non-volatile storage medium such as ROM, and an interface.

The functions of the communication unit 31, the multicast request packet processing unit 32, the request list 33, the multicast packet processing unit 34, the multicast / unicast conversion unit 35, and the unicast packet processing unit 36 provided in the corresponding switch 11 of the first embodiment are Each of these is realized by causing the CPU to execute a program that describes these functions. Further, the communication unit 31, the multicast request packet processing unit 32, the request list 33, the multicast packet processing unit 34, the multicast / unicast conversion unit 35, the unicast packet processing unit 36, and the connection port provided in the corresponding switch 11 of the second embodiment. Each function of the selection unit 37 and the counter list 38 is realized by causing the CPU to execute a program describing these functions. Further, the communication unit 31, the multicast request packet processing unit 32, the request list 33, the multicast packet processing unit 34, the multicast / unicast conversion unit 35, and the unicast packet processing unit 36 provided in the corresponding switch 11 of the modified example of the second embodiment. The functions of the connection port selection unit 37, the counter list 38, and the loop detection unit are realized by causing the CPU to execute a program describing these functions.

These programs are stored in the storage medium, read by the CPU, and executed. In addition, these programs can be stored and distributed in storage media such as magnetic disks (floppy (registered trademark) disks, hard disks, etc.), optical disks (CD-ROM, DVD, etc.), semiconductor memories, etc., and can be distributed via a network. You can also send and receive.

1 Data distribution device (corresponding switch)
2 Switch 3 Controller 10, 51-55 Transmitter 11, 13-16 Corresponding switch 12 Non-corresponding switch 21-24, 41-45 Receiver 31 Communication unit 32 Multicast request packet processing unit 33 Request list 34 Multicast packet processing unit 35 Multicast / Unicast conversion unit 36 Unicast packet processing unit 37 Connection port selection unit 38 Counter list

Claims (6)

A data distribution device that supports the multicast protocol and a packet transfer device that does not support the multicast protocol are irregularly arranged, and a downstream reception device that requests multicast distribution and an upstream transmission device that performs the multicast distribution are provided. It is a packet transfer device corresponding to the multicast protocol in the network.
A request list in which the request source IP address, which is the IP address of the receiving device, and the connection port number are registered corresponding to the multicast address,
When the multicast request packet transmitted from the receiving device is received, the multicast request packet is forwarded to the upstream side, or the unicast packet for the multicast request packet is transmitted to the downstream side and transmitted from the transmitting device. When a multicast packet is received, the unicast packet is transmitted to the downstream side, and when a unicast packet is received from the upstream side, the communication unit that forwards the unicast packet to the downstream side,
A multicast packet processing unit that extracts a multicast address from the multicast packet received by the communication unit, sets the multicast address as the source IP address of the multicast packet, and generates a new multicast packet.
When the multicast address and the requesting source IP address are extracted from the multicast request packet received by the communication unit and the multicast address is not registered in the request list, the multicast address, the requesting source IP address, and the multicast request A multicast request packet processing unit that adds the connection port number of the connection port that received the packet to the request list, and
For the new multicast packet generated by the multicast packet processing unit, the request source IP address corresponding to the multicast address of the new multicast packet is read from the request list, and the request source IP address is set as the destination IP address. As a result, the multicast / unicast conversion unit that converts the new multicast packet into a unicast packet,
A unicast packet processing unit that extracts a multicast address from the unicast packet received by the communication unit and adds the multicast address to the request list when the multicast address is not registered in the request list is provided. ,
The communication unit
When it is determined that the multicast address is set in the source IP address of the received packet, it is determined that the packet is the unicast packet, and the packet is determined to be the unicast packet.
The multicast request packet processing unit
When the multicast request packet is received by the communication unit and the multicast address extracted from the multicast request packet is registered in the request list, the unicast packet received by the communication unit is copied.
The multicast / unicast converter
For the unicast packet copied by the multicast request packet processing unit, the request source IP address corresponding to the multicast address of the unicast packet is read from the request list, and the request source IP address is set as the destination IP address. So, generate a new unicast packet,
The communication unit
A data distribution device characterized in that the new unicast packet generated by the multicast / unicast conversion unit is transmitted to the receiving device that has transmitted the multicast request packet. In the data distribution device according to claim 1,
The multicast request packet processing unit
When the multicast request packet is received by the communication unit and the multicast address extracted from the multicast request packet is registered in the request list, the new multicast packet generated by the multicast packet processing unit is copied. ,
The multicast / unicast converter
For the new multicast packet copied by the multicast request packet processing unit, the request source IP address corresponding to the multicast address of the new multicast packet is read from the request list, and the request source IP address is set as the destination IP address. By doing so, a new unicast packet is generated,
The communication unit
A data distribution device characterized in that the new unicast packet generated by the multicast / unicast conversion unit is transmitted to the receiving device that has transmitted the multicast request packet. In the data distribution device according to claim 1 or 2.
Further, a counter list in which the counter current value of the number of transmitted unicast packets corresponding to the connection port number is registered and
When the counter current value corresponding to the predetermined connection port number of the connection port for forwarding the unicast packet is read from the counter list, the counter current value is incremented, and the increment result does not exceed the predetermined set value. Select the specified connection port number and select
When the increment result exceeds the predetermined set value, the counter list includes a connection port selection unit that selects a connection port number whose current counter value does not exceed the predetermined set value.
The communication unit
A data distribution device characterized in that a unicast packet is transmitted from a connection port having the connection port number selected by the connection port selection unit. In the data distribution device according to any one of claims 1 to 3,
Further, when the unicast packet transmitted by the communication unit and the unicast packet subsequently received by the communication unit are the same, it is detected that the unicast packet has returned in a loop. A data distribution device equipped with a loop detection unit. A data distribution device that supports the multicast protocol and a packet transfer device that does not support the multicast protocol are irregularly arranged, and a downstream reception device that requests multicast distribution and an upstream transmission device that performs the multicast distribution are provided. It is a packet transfer device corresponding to the multicast protocol in the network.
The data distribution device is composed of a switch and a controller.
The switch
When the multicast request packet transmitted from the receiving device is received, the multicast request packet is forwarded to the upstream side, or the unicast packet for the multicast request packet is transmitted to the downstream side and transmitted from the transmitting device. When a multicast packet is received, the unicast packet is transmitted to the downstream side, and when a unicast packet is received from the upstream side, the communication unit is provided to transfer the unicast packet to the downstream side.
The controller
A request list in which the request source IP address, which is the IP address of the receiving device, and the connection port number are registered corresponding to the multicast address,
A multicast packet processing unit that extracts a multicast address from the multicast packet received by the communication unit, sets the multicast address as the source IP address of the multicast packet, and generates a new multicast packet.
When the multicast address and the requesting source IP address are extracted from the multicast request packet received by the communication unit and the multicast address is not registered in the request list, the multicast address, the requesting source IP address, and the multicast request A multicast request packet processing unit that adds the connection port number of the connection port that received the packet to the request list, and
For the new multicast packet generated by the multicast packet processing unit, the request source IP address corresponding to the multicast address of the new multicast packet is read from the request list, and the request source IP address is set as the destination IP address. As a result, the multicast / unicast conversion unit that converts the new multicast packet into a unicast packet,
A unicast packet processing unit that extracts a multicast address from the unicast packet received by the communication unit and adds the multicast address to the request list when the multicast address is not registered in the request list is provided. ,
The communication unit of the switch
When it is determined that the multicast address is set in the source IP address of the received packet, it is determined that the packet is the unicast packet, and the packet is determined to be the unicast packet.
The multicast request packet processing unit of the controller
When the multicast request packet is received by the communication unit and the multicast address extracted from the multicast request packet is registered in the request list, the unicast packet received by the communication unit is copied.
The multicast / unicast converter of the controller
For the unicast packet copied by the multicast request packet processing unit, the request source IP address corresponding to the multicast address of the unicast packet is read from the request list, and the request source IP address is set as the destination IP address. So, generate a new unicast packet,
The communication unit of the switch
A data distribution device characterized in that the new unicast packet generated by the multicast / unicast conversion unit is transmitted to the receiving device that has transmitted the multicast request packet. A program for causing a computer to function as the data distribution device according to any one of claims 1 to 5.

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