WO2019123630A1 - Communication device and communication method - Google Patents

Communication device and communication method Download PDF

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Publication number
WO2019123630A1
WO2019123630A1 PCT/JP2017/046126 JP2017046126W WO2019123630A1 WO 2019123630 A1 WO2019123630 A1 WO 2019123630A1 JP 2017046126 W JP2017046126 W JP 2017046126W WO 2019123630 A1 WO2019123630 A1 WO 2019123630A1
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WO
WIPO (PCT)
Prior art keywords
address
ipv6
protocol
frame
packet
Prior art date
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PCT/JP2017/046126
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French (fr)
Japanese (ja)
Inventor
松平　直樹
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富士通株式会社
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Priority to PCT/JP2017/046126 priority Critical patent/WO2019123630A1/en
Publication of WO2019123630A1 publication Critical patent/WO2019123630A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L61/00—Network arrangements, protocols or services for addressing or naming
    • H04L61/59—Network arrangements, protocols or services for addressing or naming using proxies for addressing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/46—Interconnection of networks
    • H04L12/4604—LAN interconnection over a backbone network, e.g. Internet, Frame Relay
    • H04L12/462—LAN interconnection over a bridge based backbone
    • H04L12/4625—Single bridge functionality, e.g. connection of two networks over a single bridge
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • H04L69/16—Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
    • H04L69/167—Adaptation for transition between two IP versions, e.g. between IPv4 and IPv6
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L2101/00—Indexing scheme associated with group H04L61/00
    • H04L2101/60—Types of network addresses
    • H04L2101/618—Details of network addresses
    • H04L2101/622—Layer-2 addresses, e.g. medium access control [MAC] addresses
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L2101/00—Indexing scheme associated with group H04L61/00
    • H04L2101/60—Types of network addresses
    • H04L2101/618—Details of network addresses
    • H04L2101/659—Internet protocol version 6 [IPv6] addresses
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L61/00—Network arrangements, protocols or services for addressing or naming
    • H04L61/09—Mapping addresses
    • H04L61/10—Mapping addresses of different types
    • H04L61/103—Mapping addresses of different types across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L61/00—Network arrangements, protocols or services for addressing or naming
    • H04L61/50—Address allocation
    • H04L61/5007—Internet protocol [IP] addresses
    • H04L61/5014—Internet protocol [IP] addresses using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L61/00—Network arrangements, protocols or services for addressing or naming
    • H04L61/50—Address allocation
    • H04L61/5092—Address allocation by self-assignment, e.g. picking addresses at random and testing if they are already in use

Definitions

  • the present invention relates to a communication apparatus and communication method for processing a frame or packet.
  • IP Internet Protocol
  • Ethernet registered trademark
  • the IP provides the functionality of the network layer (i.e. L3) of the Open Systems Interconnection reference model.
  • L3 packets are transmitted by IPv4 and / or IPv6. That is, in the IP network, the L3 packet is transmitted to the destination specified by the IP address.
  • Ethernet provides the data link layer (i.e. L2) functionality of the OSI reference model. Then, Ethernet transmits an L2 frame using a MAC (Media Access Control) address.
  • MAC Media Access Control
  • the transmission source device connected to the network acquires a MAC address corresponding to the IP address of the destination device as necessary. For example, in IPv4, an ARP (Address Resolution Protocol) request including the IP address of the destination device is broadcasted. Each communication device that has received the ARP request compares the IP address contained in the ARP request with its own IP address. Then, the communication devices whose IP addresses coincide with each other return the MAC address assigned to the interface of the communication device to the transmission source device. By this procedure, the transmission source device can acquire the MAC address of the destination device. In IPv6, the MAC address corresponding to the IP address is resolved using NDP (Neighbor Discovery Protocol). However, in IPv6, messages related to NDP (for example, neighbor solicitation) are multicast.
  • NDP Neighbor Discovery Protocol
  • L2overL3 a technology for logically constructing an L2 network on an L3 network.
  • L2 frame is transmitted to all the interfaces connected to the transmission path. That is, flood communication is performed.
  • each interface determines whether to receive or discard the L2 frame based on the MAC address of the L2 frame that has arrived at the input port.
  • flooding communication is performed to each node.
  • the L2 network is logically constructed on the L3 network, it is required to realize the L2 flood communication (broadcast / multicast) in the L3 network.
  • Patent Document 1 data relay of multicast using IP has been proposed (for example, Patent Document 1).
  • a method has been proposed for processing broadcast messages on the access domain (e.g. U.S. Pat. No. 5,075,015).
  • a technology for overlaying different networks on a certain network has been proposed (for example, Patent Document 3).
  • L2overL3 when constructing L2overL3, it is required to implement L2 broadcast / multicast in the L3 network.
  • L2 frames are transmitted to all or a plurality of interfaces. For this reason, it is difficult to construct L2overL3 in a large-scale network, since broadcasts are limited within the range under the router.
  • a multicast routing protocol can be used to forward multicast frames across routers.
  • multicast routing protocols are difficult to operate and are not widely used.
  • An object according to one aspect of the present invention is to provide a configuration and method for easily realizing broadcast / multicast communication of an encapsulated protocol with another protocol.
  • a communication apparatus includes an extraction unit for extracting destination information of the first frame from a first frame generated according to a first protocol, and broadcast of destination information extracted by the extraction unit.
  • An address generation unit for generating a unicast address according to a second protocol that specifies a predetermined destination when it is an address or a multicast address based on the destination information; and a unit generated by the address generation unit
  • a frame generation unit that generates a second frame according to the second protocol based on header information including a cast address and the first frame; and a second frame generated by the frame generation unit;
  • an output unit for outputting to the network according to the two protocols.
  • broadcast / multicast communication of an encapsulated protocol can be easily realized by another protocol.
  • FIG. 1 shows an example of a communication system in which a communication apparatus according to an embodiment of the present invention is used.
  • a communication system 100 according to the embodiment includes a network 1 and a plurality of communication devices 2 (2a to 2f).
  • the network 1 is implemented by an IPv6 network which forwards packets in accordance with IPv6 in this embodiment.
  • each node of the network 1 is implemented with an IPv6 router that processes IPv6 packets.
  • the IPv6 router performs routing of the received packet according to the destination address (IPv6 address) set in the header of the received packet.
  • frame and “packet” may be used without distinction.
  • a "frame” may include IPv4 packets and / or IPv6 packets.
  • the communication device 2 is connected to the network 1.
  • the communication device 2 also has an encapsulation / decapsulation function. That is, the communication device 2 can generate a frame or packet according to the second protocol from a frame or packet generated according to the first protocol. Also, the communication device 2 can regenerate a frame or packet according to the first protocol from a frame or packet according to the second protocol.
  • a host 3a that generates an IPv4 packet is connected to the communication device 2a.
  • the communication device 2a encapsulates the IPv4 packet generated by the host 3a to generate an IPv6 packet.
  • the communication device 2a decapsulates the IPv6 packet received from the network 1 and reproduces the IPv4 packet.
  • an IPv4 network is configured on the IPv6 network.
  • the communication device 2b is connected to a host 3b that generates an L2 frame (for example, an Ethernet frame, a MAC frame).
  • an L2 frame for example, an Ethernet frame, a MAC frame.
  • the communication device 2b encapsulates the L2 frame generated by the host 3b to generate an IPv6 packet.
  • the communication device 2 b decapsulates the IPv6 packet received from the network 1 and reproduces the L2 frame.
  • an L2 network is configured on the IPv6 network.
  • a network supporting protocols other than IPv6 is configured on the network 1 supporting IPv6. That is, the network 1 can be used as an underlay network by the encapsulation / decapsulation function of the communication device 2.
  • the communication device 2 can also encapsulate packets / frames received from other networks.
  • the communication device 2 d can encapsulate an IPv4 packet (or L2 frame) received via the router 4 to generate an IPv6 packet.
  • the communication device 2e can also encapsulate an L2 frame received via the bridge 5 to generate an IPv6 packet.
  • the broadcast processing server 6 is connected to the network 1 via the communication device 2 f. Then, the broadcast processing server 6 can execute processing to be executed on packets or frames to be broadcasted (or packets or frames to be multicasted) instead of each host. That is, the broadcast processing server 6 may operate as a proxy server.
  • an example of a protocol to which a packet is broadcast is ARP. That is, in IPv4, a source device requiring a MAC address of a destination device broadcasts an ARP request including the IP address of the destination device. Each host that receives the ARP request compares the IP address contained in the ARP request with its own IP address. Then, hosts whose IP addresses coincide with each other return the MAC address assigned to the interface of the host to the source apparatus of the ARP request. By this procedure, the transmission source device can acquire the MAC address of the destination device.
  • the broadcast processing server 6 acts as a proxy ARP server in this case. That is, when the broadcast processing server 6 receives an ARP request, it resolves the MAC address corresponding to the IP address included in the ARP request. Then, the broadcast processing server 6 returns the MAC address to the transmission source device of the ARP request.
  • the broadcast processing server 6 has address information indicating the correspondence between the IP address of each host and the MAC address. This address information may be given from a network administrator or may be generated by learning.
  • the above-described procedure is realized by forwarding an ARP request to the broadcast processing server 6.
  • the ARP request does not have to be forwarded to communication devices other than the broadcast processing server 6. Therefore, in the communication system 100 shown in FIG. 1, the ARP request may be forwarded to the broadcast processing server 6 by unicast communication.
  • the communication device 2 has a function of transferring the broadcasted packet or frame (or the multicasted packet or frame) to the broadcast processing server 6 by unicast communication.
  • the communication device 2a encapsulates the IPv4 packet to generate a unicast IPv6 packet.
  • This IPv6 packet contains an ARP request.
  • the destination address of this IPv6 packet designates the broadcast processing server 6 or the network to which the broadcast processing server 6 belongs. Therefore, the ARP request is transferred to the broadcast processing server 6 via the network 1 by IPv6 unicast communication. Then, the broadcast processing server 6 acquires the corresponding MAC address and transmits it to the host 3a.
  • FIG. 2 shows an example of the function of the communication apparatus according to the first embodiment of the present invention.
  • the communication device 2 performs encapsulation between IPv4 and IPv6.
  • the communication apparatus 2 includes an IPv4 router unit 11, an encapsulation processing unit 12, and an IPv6 router unit 13.
  • the communication device 2 may have a plurality of IPv4 router units 11. Also, the communication device 2 may have other functions not shown in FIG.
  • the IPv4 router unit 11 terminates an IPv4 packet received from a host or another IPv4 network. Also, the IPv4 router unit 11 transmits an IPv4 packet to a host or another IPv4 network.
  • the encapsulation processing unit 12 encapsulates the IPv4 packet terminated by the IPv4 router unit 11 to generate an IPv6 packet. Further, the encapsulation processing unit 12 decapsulates the IPv6 packet terminated by the IPv6 router unit 13 and regenerates the IPv4 packet. The configuration and operation of the encapsulation processing unit 12 will be described in detail later.
  • the IPv6 router unit 13 terminates an IPv6 packet received via the network 1. Also, the IPv6 router unit 13 outputs the IPv6 packet generated by the encapsulation processing unit 12 to the network 1.
  • the communication device 2a terminates the IPv4 packet generated by the host 3a, and generates an IPv6 packet by an encapsulation process.
  • the encapsulation is realized, for example, by adding an IPv6 header to an IPv4 packet, as shown in FIG.
  • the communication device 2a may realize encapsulation by replacing the header of the IPv4 packet (ie, the IPv4 header) with the IPv6 header.
  • the IPv6 packet generated by the communication device 2a is transferred to the communication device 2 (here, the communication device 2f) connected to the destination device via the network 1. Then, the communication device 2 f terminates the IPv6 packet and reproduces the IPv4 packet by the decapsulation process.
  • the communication device 2 f terminates the IPv6 packet and reproduces the IPv4 packet by the decapsulation process.
  • decapsulation is realized by deleting the IPv6 header from the IPv6 packet as shown in FIG.
  • the IPv6 packet is generated by replacing the header of the IPv4 packet with the IPv6 header
  • decapsulation is realized by returning the header of the IPv6 packet (that is, the IPv6 header) to the IPv4 header.
  • encapsulation of an IPv4 packet is realized by adding an IPv6 header to the IPv4 packet. Therefore, decapsulation is realized by removing the IPv6 header from the IPv6 packet.
  • FIG. 3 shows an example of the encapsulation processing unit 12 in the first embodiment.
  • the encapsulation processor 12 includes an IPv4 address extractor 21, an IPv6 address generator 22, a multiplexing ID holder 23, a prefix table 24, an IPv6 packet generator 25, and the like.
  • An IPv6 header deletion unit 26 is provided.
  • the encapsulation processing unit 12 may have other functions not shown in FIG.
  • the IPv4 address extraction unit 21 extracts an IPv4 address from the header of the IPv4 packet terminated by the IPv4 router unit 11. At this time, the IPv4 address extraction unit 21 may extract the port number of the IPv4 packet in addition to the IPv4 address.
  • the IPv6 address generation unit 22 generates an IPv6 address based on the IPv4 address extracted by the IPv4 address extraction unit 21. At this time, when the destination address of the IPv4 packet is a broadcast address or a multicast address, the IPv6 address generation unit 22 generates an IPv6 address specifying the broadcast processing server 6. Further, the IPv6 address generation unit 22 may generate an IPv6 address using the prefix stored in the prefix table 24. Alternatively, the IPv6 address generation unit 22 may generate an IPv6 address using the prefix stored in the prefix table 24 and the multiplexing ID stored in the multiplexing ID storage unit 23. The IPv6 address generation unit 22 generates a destination IPv6 address and a transmission source IPv6 address.
  • the multiplexing ID holding unit 23 holds a multiplexing ID for identifying a logical network constructed on the network 1.
  • the multiplexing ID will be further described later. Here, it is assumed that the multiplexing ID is predetermined.
  • the prefix table 24 stores prefixes corresponding to combinations of IPv4 addresses and multiplexing IDs, as shown in FIG.
  • a value representing a network to which the host abcd belongs is stored as a prefix corresponding to the combination of the IPv4 address “abcd” and the multiplexing ID “01”.
  • a prefix corresponding to the combination of the IPv4 address “abce” and the multiplexing ID “01” “value representing the network to which the host abce belongs” is stored.
  • a value representing a network to which the broadcast processing server 6 belongs is stored as a prefix corresponding to the combination of the IPv4 address specifying broadcast (or multicast) and the multiplexing ID “01”.
  • the IPv6 packet generator 25 generates an IPv6 header using the IPv6 address generated by the IPv6 address generator 22. At this time, the IPv6 address generated by the IPv6 address generation unit 22 is set in the address area of the IPv6 header. Then, the IPv6 packet generation unit 25 generates the IPv6 packet by adding the generated IPv6 header to the IPv4 packet terminated by the IPv4 router unit 11. The IPv6 packet is output to the network 1 by the IPv6 router unit 13.
  • the IPv6 header deletion unit 26 deletes the IPv6 header from the IPv6 packet received by the IPv6 router unit 13 from the network 1. That is, the IPv6 header deleting unit 26 executes a decapsulation process on the received IPv6 packet. As a result, the IPv4 packet is reproduced. The regenerated IPv4 packet is forwarded by the IPv4 router unit 11 to the destination.
  • FIG. 5 shows an example of address generation in the encapsulation process.
  • the IPv6 address comprises a prefix, a multiplexing ID, and an IPv4 address.
  • the multiplexing ID is stored in the multiplexing ID holding unit 23. Therefore, the IPv6 address generation unit 22 acquires the multiplexing ID from the multiplexing ID holding unit 23. At this time, the IPv6 address generation unit 22 acquires, for example, a multiplexing ID for identifying the logical network to which the transmission source of the IPv4 packet terminated by the IPv4 router unit 11 belongs.
  • the IPv4 address is extracted by the IPv4 address extraction unit 21 from the header of the received IPv4 packet.
  • the prefix is obtained by searching the prefix table 24 with the combination of the multiplexing ID and the IPv4 address. Then, the IPv6 address generation unit 22 generates an IPv6 address by combining the prefix, the multiplexing ID, and the IPv4 address.
  • the network 1 is assumed to forward an IPv6 packet based on the value of the prefix field of the IPv6 address.
  • the prefix is generated based on the IPv4 address. Therefore, the IPv6 packet output from the communication device 2 to the network 1 is transferred to the network to which the destination device identified by the IPv4 address belongs.
  • the IPv6 address generation unit 22 acquires “a value representing a network to which the broadcast processing server 6 belongs” from the prefix table 24 shown in FIG. Then, a destination IPv6 address is generated from the prefix, the multiplexing ID acquired from the multiplexing ID storage unit 23, and the destination IPv4 address (that is, the broadcast address) extracted from the received packet. Therefore, in this case, the IPv6 packet output from the communication device 2 to the network 1 is transferred to the network to which the broadcast processing server 6 belongs.
  • IPv4 packet whose destination IP address is a broadcast address is given to the communication device 2
  • IPv6 packet including the IPv4 packet is generated, and the IPv6 packet is unicasted from the communication device 2 to the broadcast processing server 6 Transferred by
  • An IPv4 packet whose destination IP address is a broadcast address is, for example, an ARP request.
  • the broadcast processing server 6 is a proxy ARP server.
  • the ARP request is forwarded to the proxy ARP server in unicast communication. That is, ARP is realized by unicast communication without performing broadcast / multicast. Therefore, the transmission range of the ARP request is not limited to one router.
  • the MAC address is resolved without using a multicast routing protocol which is difficult to operate.
  • the multiplexing ID is used to identify the logical network, as described above.
  • two logical networks # 1 and # 2 are identified by the multiplexing ID.
  • Logical networks # 1 and # 2 are constructed on network 1 (i.e., an IPv6 network), respectively.
  • Nodes A and B belong to the logical network # 1.
  • the node B, the node C1, and the node C2 belong to the logical network # 2.
  • Each node is represented by a prefix, a multiplexing ID, and an IPv4 address in the IPv6 address space.
  • the IPv6 address of node A is represented by a prefix, a multiplexing ID “1”, and an IPv4 address of node A.
  • the IPv6 address of node D is represented by a prefix, a multiplexing ID "2”, and an IPv4 address of node D.
  • Packet transfer is performed via the network 1 regardless of the value of the multiplexing ID. Therefore, by using the multiplexing ID, it is possible to construct a plurality of logical IPv4 networks on the IPv6 network. In other words, multiple logical IPv4 networks can be constructed on one physical network. In this case, the communication device 2 functions as a network multiplexer.
  • the network 1 forwards the IPv6 packet to the network corresponding to the prefix of the IPv6 address.
  • this prefix depends on the multiplexing ID as shown in FIG. 4 to FIG. Therefore, the IPv6 packet output from the communication device 2 to the network 1 is transferred within the range of the logical network specified by the multiplexing ID.
  • the communication device 2 that receives the IPv4 packet generates an IPv6 packet by encapsulating the IPv4 packet, and outputs the IPv6 packet to the network 1.
  • the communication device 2 when the destination address of the IPv4 packet is a broadcast address or a multicast address, the communication device 2 generates an IPv6 address specifying the network to which the broadcast processing server 6 or the broadcast processing server 6 belongs as the destination address of the IPv6 packet. Do. Therefore, the IPv4 broadcast / multicast packet is transferred to the broadcast processing server 6 by the IPv6 unicast notification.
  • IPv4 address is used as part of the IPv6 address in the example shown in FIG. 5, the first embodiment is not limited to this method. That is, the IPv6 address generated by the IPv6 address generation unit 22 may not include the IP address of the received IPv4 packet. However, IPv6 addresses are generated based on IPv4 addresses. In this case, for example, an IPv6 address specifying the broadcast processing server 6 is preferably registered in the communication device 2 in advance for the broadcast / multicast address of IPv4.
  • the IPv6 address is generated based on the IP address of the received packet, but the first embodiment is not limited to this method.
  • the IPv6 address generation unit 22 may generate an IPv6 address based on the IP address and port number of the received packet.
  • the IPv4 address and port number of the received packet may be set in the IPv6 address.
  • the prefix may be searched based on the combination of the IPv4 address and port number of the received packet.
  • an IPv6 address is generated using a multiplexing ID for identifying the logical network to which the transmission source of the IPv4 packet belongs, but the first embodiment is limited to this method. It is not a thing.
  • the IPv6 address generation unit 22 may generate an IPv6 address based on the IPv4 address and the VPN number.
  • the VPN number identifies the virtual private network to which the source of the IPv4 packet belongs.
  • the IPv4 address and the VPN number of the received packet may be set in the IPv6 address.
  • the prefix may be searched based on the combination of the IPv4 address of the received packet and the VPN number.
  • the broadcast processing server 6 is a proxy ARP server, and an IPv6 packet including an ARP request is transferred from the communication apparatus 2 to the broadcast processing server 6 by unicast communication, but the first embodiment uses this method. It is not constructed.
  • the broadcast processing server 6 may be a proxy BOOTP (Bootstrap Protocol) server, a proxy DHCP (Dynamic Host Configuration Protocol) server, a proxy BOOTP relay agent, or a proxy DHCP relay agent.
  • BOOTP and DHCP include a procedure for acquiring an IP address.
  • a DHCP client broadcasts a command requesting assignment of an IP address to multiple DHCP servers.
  • Each DHCP server notifies the DHCP client of an IP address. Then, the DHCP client selects an IP address to be used from among the notified plurality of IP addresses.
  • the broadcast processing server 6 operates as a proxy for the plurality of DHCP servers described above.
  • the DHCP client for example, the host 3a shown in FIG. 1 outputs an IPv4 packet including a command requesting allocation of an IP address.
  • the destination address of this IPv4 packet is a broadcast address.
  • the communication device 2a encapsulates this IPv4 packet to generate an IPv6 packet.
  • the destination address of this IPv6 packet designates the broadcast processing server 6.
  • an IPv6 packet including a command requesting allocation of an IP address is transferred to the broadcast processing server 6 by unicast communication.
  • IPv4 packets to be broadcasted or multicasted are encapsulated in IPv6 packets and forwarded to the broadcast processing server 6 in unicast communication.
  • the IPv6 packet to be multicast is transferred to the broadcast processing server 6 by unicast communication.
  • NDP An example of a protocol in which IPv6 packets are multicast is NDP.
  • NDP like ARP, includes a procedure to resolve the MAC address corresponding to the IP address.
  • a Neighbor Solicitation message is multicast.
  • the communication device 2 receives the multicast IPv6 packet including the proximity request message, the communication device 2 transfers the IPv6 packet to the broadcast processing server 6 by unicast communication.
  • the broadcast processing server 6 operates as a proxy NDP server.
  • an IPv6 packet including an NDP neighbor solicitation message is output from the host 3c. Then, the IPv6 packet is received by the communication device 2c connected to the host 3c. At this time, the destination IP address of this IPv6 packet is a multicast address. The multicast address of the IPv6 packet is known.
  • the communication device 2c detects that the destination IP address of the received IPv6 packet is a multicast address. Then, the communication device 2c adds an IPv6 header including an IPv6 address specifying the broadcast processing server 6 to the beginning of the received IPv6 packet. Alternatively, the communication device 2c may replace the header of the received IPv6 packet with an IPv6 header including an IPv6 address specifying the broadcast processing server 6. Then, the communication device 2 c outputs the IPv6 packet to the network 1. As a result, the IPv6 packet including the NDP neighbor solicitation message is transferred to the broadcast processing server 6 by unicast communication. The broadcast processing server 6 executes the processing of the proxy NDP server, and sends back the MAC address corresponding to the proximity request message to the host 3c.
  • the communication device 2 when the destination address of the IPv6 packet is a multicast address, the communication device 2 generates an IPv6 address specifying the broadcast processing server 6 as the destination address of the IPv6 packet. Therefore, the IPv6 multicast packet is transferred to the broadcast processing server 6 by the unicast notification of IPv6.
  • a procedure including IPv6 multicast in the prior art can be realized without performing multicast. In other words, address resolution or the like is realized without using a multicast routing protocol which is difficult to operate.
  • the communication device 2 may determine whether the destination IP address of the received packet is a multicast address or a unicast address, and may determine whether to perform encapsulation according to the determination result. In this case, if the destination IP address of the received packet is a multicast address, the communication device 2 performs encapsulation for unicast transmission to the broadcast processing server 6. On the other hand, if the destination IP address of the received packet is a unicast address, the communication device 2 outputs the packet to the network 1 without encapsulating it.
  • an L2 frame in which a broadcast address or a multicast address is set is encapsulated in an IPv6 packet and transferred to the broadcast processing server 6 by unicast communication.
  • the L2 frame is not particularly limited, and is, for example, an Ethernet frame.
  • FIG. 7 shows an example of the function of the communication apparatus according to the third embodiment of the present invention.
  • the communication device 2 performs encapsulation between the L2 frame and the IPv6 packet.
  • the communication device 2 includes a bridge unit 31, an encapsulation processing unit 32, and an IPv6 router unit 13, as shown in FIG.
  • the communication device 2 may include a plurality of bridge units 31.
  • the IPv6 router unit 13 is substantially the same in the first embodiment shown in FIG. 2 and the third embodiment shown in FIG.
  • the communication device 2 may have other functions not shown in FIG.
  • the bridge unit 31 terminates an L2 frame received from a host or another L2 network.
  • the bridge unit 31 also transmits an L2 frame to the host or another L2 network.
  • the encapsulation processing unit 32 encapsulates the L2 frame terminated by the bridge unit 31 to generate an IPv6 packet. Further, the encapsulation processing unit 32 decapsulates the IPv6 packet terminated by the IPv6 router unit 13 and regenerates the L2 frame. The configuration and operation of the encapsulation processing unit 32 will be described in detail later.
  • the communication device 2b terminates the L2 frame generated by the host 3b, and generates an IPv6 packet by an encapsulation process.
  • the encapsulation is realized, for example, by adding an IPv6 header to the L2 frame as shown in FIG.
  • the IPv6 packet generated by the communication device 2b is transferred via the network 1 to the communication device 2 (here, the communication device 2f) connected to the destination device. Then, the communication device 2 f terminates the IPv6 packet and reproduces the L2 frame by the decapsulation process. Decapsulation is realized by removing the IPv6 header from the IPv6 packet, as shown in FIG.
  • FIG. 8 shows an example of the encapsulation processing unit 32 in the third embodiment.
  • the encapsulation processing unit 32 includes a MAC address extraction unit 41, an IPv6 address generation unit 42, a multiplexing ID holding unit 43, a prefix table 44, an IPv6 packet generation unit 45, An IPv6 header deletion unit 46 is provided. Note that the encapsulation processing unit 32 may have other functions not shown in FIG.
  • the MAC address extraction unit 41 extracts the MAC address from the header of the L2 frame terminated by the bridge unit 31.
  • the IPv6 address generation unit 42 generates an IPv6 address based on the MAC address extracted by the MAC address extraction unit 41. At this time, when the destination address of the L2 frame is a broadcast address or a multicast address, the IPv6 address generation unit 42 generates an IPv6 address specifying the broadcast processing server 6 or the network to which the broadcast processing server 6 belongs. Also, the IPv6 address generation unit 42 may generate an IPv6 address using the prefix stored in the prefix table 44. Alternatively, the IPv6 address generation unit 42 may generate an IPv6 address using the prefix stored in the prefix table 44 and the multiplexing ID stored in the multiplexing ID storage unit 43.
  • the multiplexed ID holder 43 is substantially the same as the multiplexed ID holder 23 shown in FIG. That is, the multiplexing ID holding unit 43 holds the multiplexing ID for identifying the logical network constructed on the network 1.
  • the prefix table 44 stores, as shown in FIG. 9, prefixes corresponding to combinations of MAC addresses and multiplexing IDs.
  • a value representing a network to which the host pqrs belongs is stored as a prefix corresponding to the combination of the MAC address “pqrs” and the multiplexing ID “01”.
  • a value representing a network to which the host pqrt belongs is stored as a prefix corresponding to the combination of the MAC address “pqrt” and the multiplexing ID “01”.
  • a value representing a network to which the broadcast processing server 6 belongs is stored as a prefix corresponding to the combination of the MAC address specifying broadcast (or multicast) and the multiplexing ID “01”.
  • the IPv6 packet generation unit 45 generates an IPv6 header using the IPv6 address generated by the IPv6 address generation unit 42. Then, the IPv6 packet generation unit 45 generates an IPv6 packet by adding the generated IPv6 header to the L2 frame terminated by the bridge unit 31. The IPv6 packet is output to the network 1 by the IPv6 router unit 13.
  • the IPv6 header deletion unit 46 deletes the IPv6 header from the IPv6 packet received by the IPv6 router unit 13 from the network 1. That is, the IPv6 header deleting unit 46 executes a decapsulation process on the received IPv6 packet. As a result, the L2 frame is reproduced. The reproduced L2 frame is transferred by the bridge unit 31 to the destination.
  • FIG. 10 shows an example of address generation in the encapsulation process.
  • the IPv6 address is composed of a prefix, a multiplexing ID, and a MAC address.
  • the multiplexing ID is stored in the multiplexing ID holding unit 43.
  • the MAC address is extracted by the MAC address extraction unit 41 from the received L2 frame.
  • the prefix is obtained by searching the prefix table 44 with a combination of multiplexing ID and MAC address.
  • the IPv6 address generation unit 42 generates an IPv6 address by combining the prefix, the multiplexing ID, and the MAC address.
  • the network 1 transfers an IPv6 packet based on the value of the prefix area of the IPv6 address.
  • the prefix is generated based on the MAC address. Therefore, the IPv6 packet output from the communication device 2 to the network 1 is transferred to the network to which the destination device identified by the MAC address belongs.
  • the IPv6 address generation unit 42 acquires “a value representing a network to which the broadcast processing server 6 belongs” from the prefix table 44 shown in FIG. Then, a destination IPv6 address is generated from the prefix, the multiplexing ID acquired from the multiplexing ID storage unit 43, and the destination MAC address (that is, the broadcast address or the multicast address) extracted from the received frame. Therefore, in this case, the IPv6 packet output from the communication device 2 to the network 1 is transferred to the network to which the broadcast processing server 6 belongs.
  • an IPv6 packet including the L2 frame is generated, and the IPv6 packet is transmitted from the communication apparatus 2 to the broadcast processing server 6. It is transferred by unicast communication.
  • the third embodiment is not limited to this method. That is, the IPv6 address generated by the IPv6 address generation unit 42 may not include the MAC address of the received L2 frame. However, the IPv6 address is generated based on the MAC address. In this case, for example, an IPv6 address specifying the broadcast processing server 6 is preferably registered in the communication apparatus 2 in advance for the MAC address representing broadcast or multicast.
  • the broadcast processing server 6 is, for example, a proxy ARP server, a proxy NDP server, a proxy BOOTP server, a proxy DHCP server, a proxy BOOTP relay agent, or a proxy DHCP relay agent.
  • the communication device 2 includes a processor, a memory, a frame / packet memory, and an interface circuit.
  • the processor executes the communication control program stored in the memory to execute the encapsulation processing unit 12 (the IPv4 address extracting unit 21, the IPv6 address generating unit 22, the IPv6 packet generating unit 25, the IPv6 header deleting unit 26, the MAC address
  • the functions of the extraction unit 41, the IPv6 address generation unit 42, the IPv6 packet generation unit 45, and the IPv6 header deletion unit 46) are provided.
  • the processor may be a DSP (Digital Signal Processor).
  • part of the functions of the encapsulation processing unit 12 may be realized by a hardware circuit.
  • the processor and / or memory implemented in the communication device 2 may be realized by virtualization.
  • the memory stores the communication control program described above. Further, the multiplexing ID holding unit 23 and the prefix table 24 (in the examples shown in FIGS. 7 to 8, the multiplexing ID holding unit 43 and the prefix table 44) are also stored in the memory.
  • the frame / packet memory temporarily stores frames / packets received via the network.
  • the frame / packet memory also temporarily stores the frame / packet generated or reproduced by the communication device 2.
  • the interface circuit provides an interface with the network. That is, the interface circuit terminates frames / packets received via the network.
  • the interface circuit also outputs frames / packets to the network.
  • Network 2 (2a to 2f) Communication Device 6 Broadcast Processing Server 12, 32 Encapsulation Processing Unit 21 IPv4 Address Extraction Unit 22, 42 IPv6 Address Generation Unit 23, 43 Multiplexed ID Holding Unit 24, 44 Prefix Table 25, 45 IPv6 Packet generation unit 26, 46 IPv6 header deletion unit 41 MAC address extraction unit

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Abstract

A communication device is provided with an extraction unit, an address generation unit, a frame generation unit and an output unit. The extraction unit extracts, from a first frame generated according to a first protocol, destination information of the first frame. When the destination information extracted by the extraction unit is a broadcast address or a multicast address, the address generation unit generates, on the basis of the destination information, a unicast address that designates a predetermined destination and that complies with a second protocol. On the basis of header information including the unicast address generated by the address generation unit and of the first frame, the frame generation unit generates a second frame that complies with the second protocol. The output unit outputs the second frame generated by the frame generation unit to a network that complies with the second protocol.

Description

通信装置および通信方法Communication apparatus and communication method
　本発明は、フレームまたはパケットを処理する通信装置および通信方法に係わる。 The present invention relates to a communication apparatus and communication method for processing a frame or packet.
　通信ネットワークを構築するためのプロトコルとして、ＩＰ（Internet Protocol）およびイーサネット（登録商標）が広く普及している。ＩＰは、ＯＳＩ参照モデル（Open Systems Interconnection reference model）のネットワーク層（即ち、Ｌ３）の機能を提供する。そして、ＩＰネットワークでは、ＩＰｖ４及び／又はＩＰｖ６でＬ３パケットが伝送される。すなわち、ＩＰネットワークでは、ＩＰアドレスにより指定される宛先へＬ３パケットが伝送される。イーサネットは、ＯＳＩ参照モデルのデータリンク層（即ち、Ｌ２）の機能を提供する。そして、イーサネットは、ＭＡＣ（Media Access Control）アドレスを使用してＬ２フレームを伝送する。 As a protocol for constructing a communication network, IP (Internet Protocol) and Ethernet (registered trademark) are widely used. The IP provides the functionality of the network layer (i.e. L3) of the Open Systems Interconnection reference model. Then, in the IP network, L3 packets are transmitted by IPv4 and / or IPv6. That is, in the IP network, the L3 packet is transmitted to the destination specified by the IP address. Ethernet provides the data link layer (i.e. L2) functionality of the OSI reference model. Then, Ethernet transmits an L2 frame using a MAC (Media Access Control) address.
　ネットワークに接続される送信元装置は、必要に応じて、宛先装置のＩＰアドレスに対応するＭＡＣアドレスを取得する。例えば、ＩＰｖ４では、宛先装置のＩＰアドレスを含むＡＲＰ（Address Resolution Protocol）要求がブロードキャストされる。ＡＲＰ要求を受信した各通信装置は、ＡＲＰ要求に含まれるＩＰアドレスと自分のＩＰアドレスとを比較する。そして、これらのＩＰアドレスが互いに一致した通信装置は、その通信装置のインタフェースに割り当てられているＭＡＣアドレスを送信元装置に返送する。この手順により、送信元装置は、宛先装置のＭＡＣアドレスを取得できる。ＩＰｖ６では、ＮＤＰ（Neighbor Discovery Protocol）を使用してＩＰアドレスに対応するＭＡＣアドレスが解決される。ただし、ＩＰｖ６では、ＮＤＰに係わるメッセージ（たとえば、近隣要請）はマルチキャストされる。 The transmission source device connected to the network acquires a MAC address corresponding to the IP address of the destination device as necessary. For example, in IPv4, an ARP (Address Resolution Protocol) request including the IP address of the destination device is broadcasted. Each communication device that has received the ARP request compares the IP address contained in the ARP request with its own IP address. Then, the communication devices whose IP addresses coincide with each other return the MAC address assigned to the interface of the communication device to the transmission source device. By this procedure, the transmission source device can acquire the MAC address of the destination device. In IPv6, the MAC address corresponding to the IP address is resolved using NDP (Neighbor Discovery Protocol). However, in IPv6, messages related to NDP (for example, neighbor solicitation) are multicast.
　ところで、イーサネットの様々な限界を打破するために、Ｌ３ネットワーク上に論理的にＬ２ネットワークを構築する技術（Ｌ２overＬ３）が検討されている。例えば、イーサネットで伝送されるＬ２フレームをＬ３パケットにカプセル化する技術が実用化されている。ここで、Ｌ２フレームは、伝送路に接続される全てのインタフェースに送信される。すなわち、フラッディング通信が行われる。そして、各インタフェースは、入力ポートに到着したＬ２フレームのＭＡＣアドレスに基づいて、そのＬ２フレームを受信するか廃棄するかを判定する。また、宛先アドレスとしてマルチキャストアドレスが設定されたフレームに対しては、各ノードにフラッディング通信が行われる。このように、Ｌ３ネットワーク上に論理的にＬ２ネットワークを構築する場合、Ｌ３ネットワークでＬ２のフラッディング通信（ブロードキャスト／マルチキャスト）を実現することが要求される。 By the way, in order to overcome various limitations of Ethernet, a technology (L2overL3) for logically constructing an L2 network on an L3 network is being considered. For example, a technology for encapsulating an L2 frame transmitted by Ethernet in an L3 packet has been put to practical use. Here, the L2 frame is transmitted to all the interfaces connected to the transmission path. That is, flood communication is performed. Then, each interface determines whether to receive or discard the L2 frame based on the MAC address of the L2 frame that has arrived at the input port. Also, for a frame in which a multicast address is set as a destination address, flooding communication is performed to each node. As described above, when the L2 network is logically constructed on the L3 network, it is required to realize the L2 flood communication (broadcast / multicast) in the L3 network.
　関連技術として、ＩＰを用いたマルチキャストのデータ中継が提案されている（たとえば、特許文献１）。アクセスドメイン上でブロードキャストメッセージを処理する方法が提案されている（たとえば、特許文献２）。或るネットワーク上に異なるネットワークをオーバレイする技術が提案されている（たとえば、特許文献３）。 As related art, data relay of multicast using IP has been proposed (for example, Patent Document 1). A method has been proposed for processing broadcast messages on the access domain (e.g. U.S. Pat. No. 5,075,015). A technology for overlaying different networks on a certain network has been proposed (for example, Patent Document 3).
特開２００５－５１５４８号公報JP 2005-51548 A 特表２００８－５３０８８９号公報Japanese Patent Application Publication No. 2008-530889 特開２０１４－１５０３６４号公報JP, 2014-150364, A
　上述したように、Ｌ２overＬ３を構築する場合、Ｌ３ネットワークでＬ２のブロードキャスト／マルチキャストを実現することが要求される。ここで、ブロードキャスト／マルチキャストにおいては、全てまたは複数のインタフェースにＬ２フレームが送信される。このため、ブロードキャストはルータの配下の範囲内に制限されるので、大規模ネットワークでＬ２overＬ３を構築することは困難である。これに対して、マルチキャストルーティングプロトコルを使用すれば、ルータを超えてマルチキャストフレームを転送することができる。ただし、マルチキャストルーティングプロトコルは、その運用が難しく、広く普及しているとはいえない。 As described above, when constructing L2overL3, it is required to implement L2 broadcast / multicast in the L3 network. Here, in the broadcast / multicast, L2 frames are transmitted to all or a plurality of interfaces. For this reason, it is difficult to construct L2overL3 in a large-scale network, since broadcasts are limited within the range under the router. On the other hand, a multicast routing protocol can be used to forward multicast frames across routers. However, multicast routing protocols are difficult to operate and are not widely used.
　このように、従来の技術においては、カプセル化されるプロトコルのブロードキャスト／マルチキャスト通信を、他のプロトコルで実現することは容易でない。なお、この問題は、Ｌ２overＬ３において生じることに加えて、例えば、ＩＰｖ６ネットワーク上にＩＰｖ４ネットワークを構築するＩＰｖ４overＩＰｖ６等のＬ３overＬ３においても生じ得る。 Thus, in the prior art, it is not easy to implement broadcast / multicast communication of the protocol to be encapsulated by another protocol. Note that this problem may occur, for example, in L3 over L3 such as IPv4 over IPv6 that constructs an IPv4 network on an IPv6 network, in addition to the occurrence in L2 over L3.
　本発明の１つの側面に係わる目的は、カプセル化されるプロトコルのブロードキャスト／マルチキャスト通信を他のプロトコルで簡単に実現する構成および方法を提供することである。 An object according to one aspect of the present invention is to provide a configuration and method for easily realizing broadcast / multicast communication of an encapsulated protocol with another protocol.
　本発明の１つの態様の通信装置は、第１のプロトコルに従って生成された第１のフレームから前記第１のフレームの宛先情報を抽出する抽出部と、前記抽出部により抽出された宛先情報がブロードキャストアドレスまたはマルチキャストアドレスであるときに、予め決められた宛先を指定する、第２のプロトコルに従うユニキャストアドレスを、前記宛先情報に基づいて生成するアドレス生成部と、前記アドレス生成部により生成されたユニキャストアドレスを含むヘッダ情報および前記第１のフレームに基づいて、前記第２のプロトコルに従う第２のフレームを生成するフレーム生成部と、前記フレーム生成部により生成された第２のフレームを、前記第２のプロトコルに従うネットワークに出力する出力部と、を備える。 A communication apparatus according to one aspect of the present invention includes an extraction unit for extracting destination information of the first frame from a first frame generated according to a first protocol, and broadcast of destination information extracted by the extraction unit. An address generation unit for generating a unicast address according to a second protocol that specifies a predetermined destination when it is an address or a multicast address based on the destination information; and a unit generated by the address generation unit A frame generation unit that generates a second frame according to the second protocol based on header information including a cast address and the first frame; and a second frame generated by the frame generation unit; And an output unit for outputting to the network according to the two protocols.
　上述の態様によれば、カプセル化されるプロトコルのブロードキャスト／マルチキャスト通信を他のプロトコルで簡単に実現できる。 According to the above aspect, broadcast / multicast communication of an encapsulated protocol can be easily realized by another protocol.
本発明の実施形態に係わる通信装置が使用される通信システムの一例を示す図である。It is a figure which shows an example of the communication system in which the communication apparatus concerning embodiment of this invention is used. 第１の実施形態に係る通信装置の機能の一例を示す図である。It is a figure which shows an example of the function of the communication apparatus which concerns on 1st Embodiment. 第１の実施形態におけるカプセル化処理部の一例を示す図である。It is a figure which shows an example of the encapsulation process part in 1st Embodiment. 第１の実施形態で使用されるプレフィックステーブルの一例を示す図である。It is a figure which shows an example of the prefix table used in 1st Embodiment. 第１の実施形態のカプセル化処理におけるアドレス生成の一例を示す図である。It is a figure which shows an example of address generation in the encapsulation process of 1st Embodiment. 多重化ＩＤについて説明する図である。It is a figure explaining multiplexing ID. 第３の実施形態に係る通信装置の機能の一例を示す図である。It is a figure which shows an example of the function of the communication apparatus which concerns on 3rd Embodiment. 第３の実施形態におけるカプセル化処理部の一例を示す図である。It is a figure which shows an example of the encapsulation process part in 3rd Embodiment. 第３の実施形態で使用されるプレフィックステーブルの一例を示す図である。It is a figure which shows an example of the prefix table used in 3rd Embodiment. 第３の実施形態のカプセル化処理におけるアドレス生成の一例を示す図である。It is a figure which shows an example of the address generation in the encapsulation process of 3rd Embodiment.
　図１は、本発明の実施形態に係わる通信装置が使用される通信システムの一例を示す。実施形態に係わる通信システム１００は、ネットワーク１および複数の通信装置２（２ａ～２ｆ）を備える。 FIG. 1 shows an example of a communication system in which a communication apparatus according to an embodiment of the present invention is used. A communication system 100 according to the embodiment includes a network 1 and a plurality of communication devices 2 (2a to 2f).
　ネットワーク１は、この実施例では、ＩＰｖ６に従ってパケットを転送するＩＰｖ６ネットワークにより実現される。よって、ネットワーク１の各ノードには、ＩＰｖ６パケットを処理するＩＰｖ６ルータが実装されている。ＩＰｖ６ルータは、受信パケットのヘッダに設定されている宛先アドレス（ＩＰｖ６アドレス）に従って、その受信パケットのルーティングを実行する。 The network 1 is implemented by an IPv6 network which forwards packets in accordance with IPv6 in this embodiment. Thus, each node of the network 1 is implemented with an IPv6 router that processes IPv6 packets. The IPv6 router performs routing of the received packet according to the destination address (IPv6 address) set in the header of the received packet.
　なお、以下の記載では、「フレーム」および「パケット」を区別しないで使用することがある。例えば、「フレーム」は、ＩＰｖ４パケット及び／又はＩＰｖ６パケットを含むことがある。 In the following description, “frame” and “packet” may be used without distinction. For example, a "frame" may include IPv4 packets and / or IPv6 packets.
　通信装置２は、ネットワーク１に接続される。また、通信装置２は、カプセル化／デカプセル化機能を備える。すなわち、通信装置２は、第１のプロトコルに従って生成されたフレームまたはパケットから第２のプロトコルに従うフレームまたはパケットを生成することができる。また、通信装置２は、第２のプロトコルに従うフレームまたはパケットから第１のプロトコルに従うフレームまたはパケットを再生することができる。 The communication device 2 is connected to the network 1. The communication device 2 also has an encapsulation / decapsulation function. That is, the communication device 2 can generate a frame or packet according to the second protocol from a frame or packet generated according to the first protocol. Also, the communication device 2 can regenerate a frame or packet according to the first protocol from a frame or packet according to the second protocol.
　たとえば、通信装置２ａには、ＩＰｖ４パケットを生成するホスト３ａが接続されている。この場合、通信装置２ａは、ホスト３ａにより生成されるＩＰｖ４パケットをカプセル化してＩＰｖ６パケットを生成する。また、通信装置２ａは、ネットワーク１から受信するＩＰｖ６パケットをデカプセル化してＩＰｖ４パケットを再生する。なお、このケースでは、ＩＰｖ６ネットワーク上にＩＰｖ４ネットワークが構成される。 For example, a host 3a that generates an IPv4 packet is connected to the communication device 2a. In this case, the communication device 2a encapsulates the IPv4 packet generated by the host 3a to generate an IPv6 packet. Also, the communication device 2a decapsulates the IPv6 packet received from the network 1 and reproduces the IPv4 packet. In this case, an IPv4 network is configured on the IPv6 network.
　通信装置２ｂには、Ｌ２フレーム（例えば、イーサネットフレーム、ＭＡＣフレーム）を生成するホスト３ｂが接続されている。この場合、通信装置２ｂは、ホスト３ｂにより生成されるＬ２フレームをカプセル化してＩＰｖ６パケットを生成する。また、通信装置２ｂは、ネットワーク１から受信するＩＰｖ６パケットをデカプセル化してＬ２フレームを再生する。なお、このケースでは、ＩＰｖ６ネットワーク上にＬ２ネットワークが構成される。 The communication device 2b is connected to a host 3b that generates an L2 frame (for example, an Ethernet frame, a MAC frame). In this case, the communication device 2b encapsulates the L2 frame generated by the host 3b to generate an IPv6 packet. Also, the communication device 2 b decapsulates the IPv6 packet received from the network 1 and reproduces the L2 frame. In this case, an L2 network is configured on the IPv6 network.
　このように、通信システム１００においては、ＩＰｖ６以外のプロトコルをサポートするネットワークがＩＰｖ６をサポートするネットワーク１上に構成される。すなわち、ネットワーク１は、通信装置２のカプセル化／デカプセル化機能により、アンダーレイネットワークとして使用され得る。 Thus, in the communication system 100, a network supporting protocols other than IPv6 is configured on the network 1 supporting IPv6. That is, the network 1 can be used as an underlay network by the encapsulation / decapsulation function of the communication device 2.
　なお、通信装置２は、他のネットワークから受信するパケット／フレームをカプセル化することもできる。例えば、通信装置２ｄは、ルータ４を介して受信するＩＰｖ４パケット（または、Ｌ２フレーム）をカプセル化してＩＰｖ６パケットを生成できる。また、通信装置２ｅは、ブリッジ５を介して受信するＬ２フレームをカプセル化してＩＰｖ６パケットを生成できる。 The communication device 2 can also encapsulate packets / frames received from other networks. For example, the communication device 2 d can encapsulate an IPv4 packet (or L2 frame) received via the router 4 to generate an IPv6 packet. The communication device 2e can also encapsulate an L2 frame received via the bridge 5 to generate an IPv6 packet.
　ブロードキャスト処理サーバ６は、通信装置２ｆを介してネットワーク１に接続されている。そして、ブロードキャスト処理サーバ６は、ブロードキャストされるパケットまたはフレーム（或いは、マルチキャストされるパケットまたはフレーム）に対して実行すべき処理を、各ホストの代わりに実行することができる。すなわち、ブロードキャスト処理サーバ６は、プロキシサーバとして動作することがある。 The broadcast processing server 6 is connected to the network 1 via the communication device 2 f. Then, the broadcast processing server 6 can execute processing to be executed on packets or frames to be broadcasted (or packets or frames to be multicasted) instead of each host. That is, the broadcast processing server 6 may operate as a proxy server.
　ここで、パケットがブロードキャストされるプロトコルの一例はＡＲＰである。すなわち、ＩＰｖ４では、宛先装置のＭＡＣアドレスを必要とする送信元装置は、その宛先装置のＩＰアドレスを含むＡＲＰ要求をブロードキャストする。ＡＲＰ要求を受信した各ホストは、ＡＲＰ要求に含まれるＩＰアドレスと自分のＩＰアドレスとを比較する。そして、これらのＩＰアドレスが互いに一致したホストは、そのホストのインタフェースに割り当てられているＭＡＣアドレスをＡＲＰ要求の送信元装置に返送する。この手順により、送信元装置は、宛先装置のＭＡＣアドレスを取得できる。 Here, an example of a protocol to which a packet is broadcast is ARP. That is, in IPv4, a source device requiring a MAC address of a destination device broadcasts an ARP request including the IP address of the destination device. Each host that receives the ARP request compares the IP address contained in the ARP request with its own IP address. Then, hosts whose IP addresses coincide with each other return the MAC address assigned to the interface of the host to the source apparatus of the ARP request. By this procedure, the transmission source device can acquire the MAC address of the destination device.
　ブロードキャスト処理サーバ６は、このケースでは、プロキシＡＲＰサーバとして動作する。すなわち、ブロードキャスト処理サーバ６は、ＡＲＰ要求を受信すると、そのＡＲＰ要求に含まれるＩＰアドレスに対応するＭＡＣアドレスを解決する。そして、ブロードキャスト処理サーバ６は、このＭＡＣアドレスをＡＲＰ要求の送信元装置に返送する。なお、ブロードキャスト処理サーバ６は、各ホストのＩＰアドレスとＭＡＣアドレスとの対応関係を表すアドレス情報を有しているものとする。このアドレス情報は、ネットワーク管理者から与えられてもよいし、学習により生成されるようにしてもよい。 The broadcast processing server 6 acts as a proxy ARP server in this case. That is, when the broadcast processing server 6 receives an ARP request, it resolves the MAC address corresponding to the IP address included in the ARP request. Then, the broadcast processing server 6 returns the MAC address to the transmission source device of the ARP request. The broadcast processing server 6 has address information indicating the correspondence between the IP address of each host and the MAC address. This address information may be given from a network administrator or may be generated by learning.
　上述の手順は、ＡＲＰ要求をブロードキャスト処理サーバ６に転送することで実現される。換言すれば、このケースでは、ＡＲＰ要求は、ブロードキャスト処理サーバ６以外の通信装置に転送される必要はない。したがって、図１に示す通信システム１００においては、ＡＲＰ要求は、ユニキャスト通信でブロードキャスト処理サーバ６に転送されるようにしてもよい。 The above-described procedure is realized by forwarding an ARP request to the broadcast processing server 6. In other words, in this case, the ARP request does not have to be forwarded to communication devices other than the broadcast processing server 6. Therefore, in the communication system 100 shown in FIG. 1, the ARP request may be forwarded to the broadcast processing server 6 by unicast communication.
　そこで、通信装置２は、ブロードキャストされるパケットまたはフレーム（或いは、マルチキャストされるパケットまたはフレーム）を、ユニキャスト通信でブロードキャスト処理サーバ６に転送する機能を備える。たとえば、図１に示すホスト３ａによりＡＲＰ要求を含むブロードキャストＩＰｖ４パケットが生成されたときは、通信装置２ａは、そのＩＰｖ４パケットをカプセル化してユニキャストＩＰｖ６パケットを生成する。このＩＰｖ６パケットは、ＡＲＰ要求を含む。また、このＩＰｖ６パケットの宛先アドレスは、ブロードキャスト処理サーバ６またはブロードキャスト処理サーバ６が属するネットワークを指定する。したがって、ＡＲＰ要求は、ＩＰｖ６のユニキャスト通信により、ネットワーク１を介してブロードキャスト処理サーバ６に転送される。そうすると、ブロードキャスト処理サーバ６は、対応するＭＡＣアドレスを取得してホスト３ａに送信する。 Therefore, the communication device 2 has a function of transferring the broadcasted packet or frame (or the multicasted packet or frame) to the broadcast processing server 6 by unicast communication. For example, when the host 3a shown in FIG. 1 generates a broadcast IPv4 packet including an ARP request, the communication device 2a encapsulates the IPv4 packet to generate a unicast IPv6 packet. This IPv6 packet contains an ARP request. Also, the destination address of this IPv6 packet designates the broadcast processing server 6 or the network to which the broadcast processing server 6 belongs. Therefore, the ARP request is transferred to the broadcast processing server 6 via the network 1 by IPv6 unicast communication. Then, the broadcast processing server 6 acquires the corresponding MAC address and transmits it to the host 3a.
　＜第１の実施形態＞
　図２は、本発明の第１の実施形態に係る通信装置の機能の一例を示す。この例では、通信装置２は、ＩＰｖ４とＩＰｖ６との間でカプセル化を行う。 First Embodiment
FIG. 2 shows an example of the function of the communication apparatus according to the first embodiment of the present invention. In this example, the communication device 2 performs encapsulation between IPv4 and IPv6.
　通信装置２は、図２に示すように、ＩＰｖ４ルータ部１１、カプセル化処理部１２、ＩＰｖ６ルータ部１３を備える。なお、通信装置２は、複数のＩＰｖ４ルータ部１１を備えていてもよい。また、通信装置２は、図２に示していない他の機能を備えていてもよい。 As shown in FIG. 2, the communication apparatus 2 includes an IPv4 router unit 11, an encapsulation processing unit 12, and an IPv6 router unit 13. The communication device 2 may have a plurality of IPv4 router units 11. Also, the communication device 2 may have other functions not shown in FIG.
　ＩＰｖ４ルータ部１１は、ホストまたは他のＩＰｖ４ネットワークから受信するＩＰｖ４パケットを終端する。また、ＩＰｖ４ルータ部１１は、ホストまたは他のＩＰｖ４ネットワークにＩＰｖ４パケットを送信する。 The IPv4 router unit 11 terminates an IPv4 packet received from a host or another IPv4 network. Also, the IPv4 router unit 11 transmits an IPv4 packet to a host or another IPv4 network.
　カプセル化処理部１２は、ＩＰｖ４ルータ部１１により終端されたＩＰｖ４パケットをカプセル化してＩＰｖ６パケットを生成する。また、カプセル化処理部１２は、ＩＰｖ６ルータ部１３により終端されたＩＰｖ６パケットをデカプセル化してＩＰｖ４パケットを再生する。なお、カプセル化処理部１２の構成および動作については、後で詳しく説明する。 The encapsulation processing unit 12 encapsulates the IPv4 packet terminated by the IPv4 router unit 11 to generate an IPv6 packet. Further, the encapsulation processing unit 12 decapsulates the IPv6 packet terminated by the IPv6 router unit 13 and regenerates the IPv4 packet. The configuration and operation of the encapsulation processing unit 12 will be described in detail later.
　ＩＰｖ６ルータ部１３は、ネットワーク１を介して受信するＩＰｖ６パケットを終端する。また、ＩＰｖ６ルータ部１３は、カプセル化処理部１２により生成されるＩＰｖ６パケットをネットワーク１に出力する。 The IPv6 router unit 13 terminates an IPv6 packet received via the network 1. Also, the IPv6 router unit 13 outputs the IPv6 packet generated by the encapsulation processing unit 12 to the network 1.
　図２に示す例では、通信装置２ａは、ホスト３ａにより生成されるＩＰｖ４パケットを終端し、カプセル化処理によりＩＰｖ６パケットを生成する。カプセル化は、例えば、図２に示すように、ＩＰｖ４パケットにＩＰｖ６ヘッダを付加することにより実現される。或いは、通信装置２ａは、ＩＰｖ４パケットのヘッダ（即ち、ＩＰｖ４ヘッダ）をＩＰｖ６ヘッダに置き換えることによりカプセル化を実現してもよい。 In the example shown in FIG. 2, the communication device 2a terminates the IPv4 packet generated by the host 3a, and generates an IPv6 packet by an encapsulation process. The encapsulation is realized, for example, by adding an IPv6 header to an IPv4 packet, as shown in FIG. Alternatively, the communication device 2a may realize encapsulation by replacing the header of the IPv4 packet (ie, the IPv4 header) with the IPv6 header.
　通信装置２ａにより生成されたＩＰｖ６パケットは、ネットワーク１を介して、宛先装置に接続される通信装置２（ここでは、通信装置２ｆ）に転送される。そうすると、通信装置２ｆは、このＩＰｖ６パケットを終端し、デカプセル化処理によりＩＰｖ４パケットを再生する。ＩＰｖ４パケットにＩＰｖ６ヘッダを付加することによりＩＰｖ６パケットが生成されるケースでは、デカプセル化は、図２に示すように、ＩＰｖ６パケットからＩＰｖ６ヘッダを削除することにより実現される。ただし、ＩＰｖ４パケットのヘッダをＩＰｖ６ヘッダに置き換えることによりＩＰｖ６パケットが生成されるケースでは、デカプセル化は、ＩＰｖ６パケットのヘッダ（即ち、ＩＰｖ６ヘッダ）をＩＰｖ４ヘッダに戻すことにより実現される。 The IPv6 packet generated by the communication device 2a is transferred to the communication device 2 (here, the communication device 2f) connected to the destination device via the network 1. Then, the communication device 2 f terminates the IPv6 packet and reproduces the IPv4 packet by the decapsulation process. In the case where an IPv6 packet is generated by adding an IPv6 header to an IPv4 packet, decapsulation is realized by deleting the IPv6 header from the IPv6 packet as shown in FIG. However, in the case where the IPv6 packet is generated by replacing the header of the IPv4 packet with the IPv6 header, decapsulation is realized by returning the header of the IPv6 packet (that is, the IPv6 header) to the IPv4 header.
　なお、以下の記載では、ＩＰｖ４パケットのカプセル化は、ＩＰｖ４パケットにＩＰｖ６ヘッダを付加することにより実現されるものとする。よって、デカプセル化は、ＩＰｖ６パケットからＩＰｖ６ヘッダを削除することにより実現される。 In the following description, encapsulation of an IPv4 packet is realized by adding an IPv6 header to the IPv4 packet. Therefore, decapsulation is realized by removing the IPv6 header from the IPv6 packet.
　図３は、第１の実施形態におけるカプセル化処理部１２の一例を示す。第１の実施形態では、カプセル化処理部１２は、図３に示すように、ＩＰｖ４アドレス抽出部２１、ＩＰｖ６アドレス生成部２２、多重化ＩＤ保持部２３、プレフィックステーブル２４、ＩＰｖ６パケット生成部２５、ＩＰｖ６ヘッダ削除部２６を備える。なお、カプセル化処理部１２は、図３に示していない他の機能を備えていてもよい。 FIG. 3 shows an example of the encapsulation processing unit 12 in the first embodiment. In the first embodiment, as shown in FIG. 3, the encapsulation processor 12 includes an IPv4 address extractor 21, an IPv6 address generator 22, a multiplexing ID holder 23, a prefix table 24, an IPv6 packet generator 25, and the like. An IPv6 header deletion unit 26 is provided. The encapsulation processing unit 12 may have other functions not shown in FIG.
　ＩＰｖ４アドレス抽出部２１は、ＩＰｖ４ルータ部１１により終端されたＩＰｖ４パケットのヘッダからＩＰｖ４アドレスを抽出する。このとき、ＩＰｖ４アドレス抽出部２１は、ＩＰｖ４アドレスに加えて、ＩＰｖ４パケットのポート番号を抽出してもよい。 The IPv4 address extraction unit 21 extracts an IPv4 address from the header of the IPv4 packet terminated by the IPv4 router unit 11. At this time, the IPv4 address extraction unit 21 may extract the port number of the IPv4 packet in addition to the IPv4 address.
　ＩＰｖ６アドレス生成部２２は、ＩＰｖ４アドレス抽出部２１により抽出されたＩＰｖ４アドレスに基づいて、ＩＰｖ６アドレスを生成する。このとき、ＩＰｖ４パケットの宛先アドレスがブロードキャストアドレスまたはマルチキャストアドレスであったときは、ＩＰｖ６アドレス生成部２２は、ブロードキャスト処理サーバ６を指定するＩＰｖ６アドレスを生成する。また、ＩＰｖ６アドレス生成部２２は、プレフィックステーブル２４に格納されているプレフィックスを利用してＩＰｖ６アドレスを生成してもよい。或いは、ＩＰｖ６アドレス生成部２２は、プレフィックステーブル２４に格納されているプレフィックスおよび多重化ＩＤ保持部２３に格納されている多重化ＩＤを利用してＩＰｖ６アドレスを生成してもよい。なお、ＩＰｖ６アドレス生成部２２は、宛先ＩＰｖ６アドレスおよび送信元ＩＰｖ６アドレスを生成する。 The IPv6 address generation unit 22 generates an IPv6 address based on the IPv4 address extracted by the IPv4 address extraction unit 21. At this time, when the destination address of the IPv4 packet is a broadcast address or a multicast address, the IPv6 address generation unit 22 generates an IPv6 address specifying the broadcast processing server 6. Further, the IPv6 address generation unit 22 may generate an IPv6 address using the prefix stored in the prefix table 24. Alternatively, the IPv6 address generation unit 22 may generate an IPv6 address using the prefix stored in the prefix table 24 and the multiplexing ID stored in the multiplexing ID storage unit 23. The IPv6 address generation unit 22 generates a destination IPv6 address and a transmission source IPv6 address.
　多重化ＩＤ保持部２３は、ネットワーク１上に構築される論理ネットワークを識別する多重化ＩＤを保持する。多重化ＩＤについては後でさらに説明する。ここでは、多重化ＩＤは、予め決められているものとする。 The multiplexing ID holding unit 23 holds a multiplexing ID for identifying a logical network constructed on the network 1. The multiplexing ID will be further described later. Here, it is assumed that the multiplexing ID is predetermined.
　プレフィックステーブル２４は、図４に示すように、ＩＰｖ４アドレスおよび多重化ＩＤの組合せに対応するプレフィックスを格納する。図４に示す例では、ＩＰｖ４アドレス「abcd」および多重化ＩＤ「01」の組合せに対応するプレフィックスとして「ホストａｂｃｄが属するネットワークを表す値」が格納されている。ＩＰｖ４アドレス「abce」および多重化ＩＤ「01」の組合せに対応するプレフィックスとして「ホストａｂｃｅが属するネットワークを表す値」が格納されている。さらに、ブロードキャスト（または、マルチキャスト）を指定するＩＰｖ４アドレスおよび多重化ＩＤ「01」の組合せに対応するプレフィックスとして「ブロードキャスト処理サーバ６が属するネットワークを表す値」が格納されている。 The prefix table 24 stores prefixes corresponding to combinations of IPv4 addresses and multiplexing IDs, as shown in FIG. In the example shown in FIG. 4, “a value representing a network to which the host abcd belongs” is stored as a prefix corresponding to the combination of the IPv4 address “abcd” and the multiplexing ID “01”. As a prefix corresponding to the combination of the IPv4 address “abce” and the multiplexing ID “01”, “value representing the network to which the host abce belongs” is stored. Furthermore, “a value representing a network to which the broadcast processing server 6 belongs” is stored as a prefix corresponding to the combination of the IPv4 address specifying broadcast (or multicast) and the multiplexing ID “01”.
　ＩＰｖ６パケット生成部２５は、ＩＰｖ６アドレス生成部２２により生成されるＩＰｖ６アドレスを用いてＩＰｖ６ヘッダを生成する。このとき、ＩＰｖ６アドレス生成部２２により生成されるＩＰｖ６アドレスがＩＰｖ６ヘッダのアドレス領域に設定される。そして、ＩＰｖ６パケット生成部２５は、ＩＰｖ４ルータ部１１により終端されたＩＰｖ４パケットに、生成したＩＰｖ６ヘッダを付加することでＩＰｖ６パケットを生成する。このＩＰｖ６パケットは、ＩＰｖ６ルータ部１３により、ネットワーク１に出力される。 The IPv6 packet generator 25 generates an IPv6 header using the IPv6 address generated by the IPv6 address generator 22. At this time, the IPv6 address generated by the IPv6 address generation unit 22 is set in the address area of the IPv6 header. Then, the IPv6 packet generation unit 25 generates the IPv6 packet by adding the generated IPv6 header to the IPv4 packet terminated by the IPv4 router unit 11. The IPv6 packet is output to the network 1 by the IPv6 router unit 13.
　ＩＰｖ６ヘッダ削除部２６は、ＩＰｖ６ルータ部１３がネットワーク１から受信したＩＰｖ６パケットからＩＰｖ６ヘッダを削除する。即ち、ＩＰｖ６ヘッダ削除部２６は、受信ＩＰｖ６パケットに対してデカプセル化処理を実行する。この結果、ＩＰｖ４パケットが再生される。再生されたＩＰｖ４パケットは、ＩＰｖ４ルータ部１１により、宛先に転送される。 The IPv6 header deletion unit 26 deletes the IPv6 header from the IPv6 packet received by the IPv6 router unit 13 from the network 1. That is, the IPv6 header deleting unit 26 executes a decapsulation process on the received IPv6 packet. As a result, the IPv4 packet is reproduced. The regenerated IPv4 packet is forwarded by the IPv4 router unit 11 to the destination.
　図５は、カプセル化処理におけるアドレス生成の一例を示す。この例では、ＩＰｖ６アドレスは、プレフィックス、多重化ＩＤ、ＩＰｖ４アドレスから構成される。多重化ＩＤは、多重化ＩＤ保持部２３に格納されている。よって、ＩＰｖ６アドレス生成部２２は、多重化ＩＤ保持部２３から多重化ＩＤを取得する。このとき、ＩＰｖ６アドレス生成部２２は、例えば、ＩＰｖ４ルータ部１１により終端されたＩＰｖ４パケットの送信元が属する論理ネットワークを識別する多重化ＩＤを取得する。ＩＰｖ４アドレスは、ＩＰｖ４アドレス抽出部２１により受信ＩＰｖ４パケットのヘッダから抽出される。プレフィックスは、多重化ＩＤおよびＩＰｖ４アドレスの組合せでプレフィックステーブル２４を検索することにより得られる。そして、ＩＰｖ６アドレス生成部２２は、プレフィックス、多重化ＩＤ、ＩＰｖ４アドレスを結合することでＩＰｖ６アドレスを生成する。 FIG. 5 shows an example of address generation in the encapsulation process. In this example, the IPv6 address comprises a prefix, a multiplexing ID, and an IPv4 address. The multiplexing ID is stored in the multiplexing ID holding unit 23. Therefore, the IPv6 address generation unit 22 acquires the multiplexing ID from the multiplexing ID holding unit 23. At this time, the IPv6 address generation unit 22 acquires, for example, a multiplexing ID for identifying the logical network to which the transmission source of the IPv4 packet terminated by the IPv4 router unit 11 belongs. The IPv4 address is extracted by the IPv4 address extraction unit 21 from the header of the received IPv4 packet. The prefix is obtained by searching the prefix table 24 with the combination of the multiplexing ID and the IPv4 address. Then, the IPv6 address generation unit 22 generates an IPv6 address by combining the prefix, the multiplexing ID, and the IPv4 address.
　プレフィックスの長さは、多重化ＩＤのビット数に応じて決定される。例えば、ＩＰｖ６アドレスがプレフィックス、多重化ＩＤ、ＩＰｖ４アドレスのみから構成され、且つ、多重化ＩＤが８ビットである場合には、プレフィックスの長さは、８８（＝１２８－８－３２）ビットである。 The length of the prefix is determined according to the number of bits of the multiplexing ID. For example, if the IPv6 address consists only of a prefix, a multiplexing ID, and an IPv4 address, and the multiplexing ID is 8 bits, then the length of the prefix is 88 (= 128-8-32) bits .
　ネットワーク１は、この実施例では、ＩＰｖ６アドレスのプレフィックス領域の値に基づいてＩＰｖ６パケットを転送するものとする。ここで、プレフィックスは、ＩＰｖ４アドレスに基づいて生成される。したがって、通信装置２からネットワーク１に出力されるＩＰｖ６パケットは、ＩＰｖ４アドレスにより識別される宛先装置が属するネットワークに転送される。 In this embodiment, the network 1 is assumed to forward an IPv6 packet based on the value of the prefix field of the IPv6 address. Here, the prefix is generated based on the IPv4 address. Therefore, the IPv6 packet output from the communication device 2 to the network 1 is transferred to the network to which the destination device identified by the IPv4 address belongs.
　受信ＩＰｖ４パケットの宛先ＩＰアドレスがブロードキャストアドレスであるときは、ＩＰｖ６アドレス生成部２２は、図４に示すプレフィックステーブル２４から「ブロードキャスト処理サーバ６が属するネットワークを表す値」を取得する。そして、このプレフィックス、多重化ＩＤ保持部２３から取得した多重化ＩＤ、および受信パケットから抽出した宛先ＩＰｖ４アドレス（即ち、ブロードキャストアドレス）から宛先ＩＰｖ６アドレスが生成される。したがって、この場合、通信装置２からネットワーク１に出力されるＩＰｖ６パケットは、ブロードキャスト処理サーバ６が属するネットワークに転送される。すなわち、宛先ＩＰアドレスがブロードキャストアドレスであるＩＰｖ４パケットが通信装置２に与えられたときは、そのＩＰｖ４パケットを含むＩＰｖ６パケットが生成され、そのＩＰｖ６パケットが通信装置２からブロードキャスト処理サーバ６にユニキャスト通信で転送される。 When the destination IP address of the received IPv4 packet is a broadcast address, the IPv6 address generation unit 22 acquires “a value representing a network to which the broadcast processing server 6 belongs” from the prefix table 24 shown in FIG. Then, a destination IPv6 address is generated from the prefix, the multiplexing ID acquired from the multiplexing ID storage unit 23, and the destination IPv4 address (that is, the broadcast address) extracted from the received packet. Therefore, in this case, the IPv6 packet output from the communication device 2 to the network 1 is transferred to the network to which the broadcast processing server 6 belongs. That is, when an IPv4 packet whose destination IP address is a broadcast address is given to the communication device 2, an IPv6 packet including the IPv4 packet is generated, and the IPv6 packet is unicasted from the communication device 2 to the broadcast processing server 6 Transferred by
　なお、宛先ＩＰアドレスがブロードキャストアドレスであるＩＰｖ４パケットは、例えば、ＡＲＰ要求である。また、ブロードキャスト処理サーバ６は、プロキシＡＲＰサーバである。この場合、ＡＲＰ要求は、ユニキャスト通信でプロキシＡＲＰサーバに転送される。即ち、ブロードキャスト／マルチキャストを行うことなく、ユニキャスト通信でＡＲＰが実現される。したがって、ＡＲＰ要求の送信範囲は、１台のルータの配下に限定されない。また、多数のルータを含む大規模なネットワークにおいても、運用が難しいマルチキャストルーティングプロトコルを使用することなくＭＡＣアドレスが解決される。 An IPv4 packet whose destination IP address is a broadcast address is, for example, an ARP request. Also, the broadcast processing server 6 is a proxy ARP server. In this case, the ARP request is forwarded to the proxy ARP server in unicast communication. That is, ARP is realized by unicast communication without performing broadcast / multicast. Therefore, the transmission range of the ARP request is not limited to one router. In addition, even in a large network including a large number of routers, the MAC address is resolved without using a multicast routing protocol which is difficult to operate.
　次に、多重化ＩＤについて説明する。多重化ＩＤは、上述したように、論理ネットワークを識別するために使用される。図６に示す例では、２つの論理ネットワーク＃１、＃２が多重化ＩＤにより識別される。論理ネットワーク＃１、＃２は、それぞれネットワーク１（すなわち、ＩＰｖ６ネットワーク）上に構築される。論理ネットワーク＃１には、ノードＡ、ノードＢが属する。また、論理ネットワーク＃２には、ノードＢ、ノードＣ１、ノードＣ２が属する。 Next, the multiplexing ID will be described. The multiplexing ID is used to identify the logical network, as described above. In the example shown in FIG. 6, two logical networks # 1 and # 2 are identified by the multiplexing ID. Logical networks # 1 and # 2 are constructed on network 1 (i.e., an IPv6 network), respectively. Nodes A and B belong to the logical network # 1. The node B, the node C1, and the node C2 belong to the logical network # 2.
　各ノードは、ＩＰｖ６アドレス空間においては、プレフィックス、多重化ＩＤ、ＩＰｖ４アドレスで表現される。例えば、ノードＡのＩＰｖ６アドレスは、プレフィックス、多重化ＩＤ「１」、およびノードＡのＩＰｖ４アドレスで表される。また、ノードＤのＩＰｖ６アドレスは、プレフィックス、多重化ＩＤ「２」、およびノードＤのＩＰｖ４アドレスで表される。 Each node is represented by a prefix, a multiplexing ID, and an IPv4 address in the IPv6 address space. For example, the IPv6 address of node A is represented by a prefix, a multiplexing ID “1”, and an IPv4 address of node A. Also, the IPv6 address of node D is represented by a prefix, a multiplexing ID "2", and an IPv4 address of node D.
　パケット転送は、多重化ＩＤの値にかかわらず、ネットワーク１を介して行われる。よって、多重化ＩＤを用いることで、ＩＰｖ６ネットワーク上に複数の論理的なＩＰｖ４ネットワークを構築することができる。換言すれば、１つの物理的なネットワーク上に、複数の論理的なＩＰｖ４ネットワークを構築することができる。この場合、通信装置２は、ネットワーク多重化装置として機能する。 Packet transfer is performed via the network 1 regardless of the value of the multiplexing ID. Therefore, by using the multiplexing ID, it is possible to construct a plurality of logical IPv4 networks on the IPv6 network. In other words, multiple logical IPv4 networks can be constructed on one physical network. In this case, the communication device 2 functions as a network multiplexer.
　ただし、この実施例では、ネットワーク１は、ＩＰｖ６アドレスのプレフィックスに対応するネットワークにＩＰｖ６パケットを転送する。ここで、このプレフィックスは、図４～図５に示すように、多重化ＩＤに依存する。よって、通信装置２からネットワーク１に出力されるＩＰｖ６パケットは、多重化ＩＤにより指定される論理ネットワークの範囲内で転送される。 However, in this embodiment, the network 1 forwards the IPv6 packet to the network corresponding to the prefix of the IPv6 address. Here, this prefix depends on the multiplexing ID as shown in FIG. 4 to FIG. Therefore, the IPv6 packet output from the communication device 2 to the network 1 is transferred within the range of the logical network specified by the multiplexing ID.
　このように、第１の実施形態では、ＩＰｖ４パケットを受信した通信装置２は、そのＩＰｖ４パケットをカプセル化することでＩＰｖ６パケットを生成し、そのＩＰｖ６パケットをネットワーク１に出力する。ここで、ＩＰｖ４パケットの宛先アドレスがブロードキャストアドレスまたはマルチキャストアドレスであるときは、通信装置２は、ＩＰｖ６パケットの宛先アドレスとして、ブロードキャスト処理サーバ６またはブロードキャスト処理サーバ６が属するネットワークを指定するＩＰｖ６アドレスを生成する。よって、ＩＰｖ４のブロードキャスト／マルチキャストパケットは、ＩＰｖ６のユニキャスト通知により、ブロードキャスト処理サーバ６に転送される。 As described above, in the first embodiment, the communication device 2 that receives the IPv4 packet generates an IPv6 packet by encapsulating the IPv4 packet, and outputs the IPv6 packet to the network 1. Here, when the destination address of the IPv4 packet is a broadcast address or a multicast address, the communication device 2 generates an IPv6 address specifying the network to which the broadcast processing server 6 or the broadcast processing server 6 belongs as the destination address of the IPv6 packet. Do. Therefore, the IPv4 broadcast / multicast packet is transferred to the broadcast processing server 6 by the IPv6 unicast notification.
　なお、図５に示す実施例では、ＩＰｖ４アドレスがＩＰｖ６アドレスの一部として使用されるが、第１の実施形態はこの方式に限定されるものではない。すなわち、ＩＰｖ６アドレス生成部２２により生成されるＩＰｖ６アドレスは、受信ＩＰｖ４パケットのＩＰアドレスを含まなくてもよい。ただし、ＩＰｖ６アドレスは、ＩＰｖ４アドレスに基づいて生成される。この場合、例えば、ＩＰｖ４のブロードキャスト／マルチキャストアドレスに対して、ブロードキャスト処理サーバ６を指定するＩＰｖ６アドレスが予め通信装置２に登録されていることが好ましい。 Although the IPv4 address is used as part of the IPv6 address in the example shown in FIG. 5, the first embodiment is not limited to this method. That is, the IPv6 address generated by the IPv6 address generation unit 22 may not include the IP address of the received IPv4 packet. However, IPv6 addresses are generated based on IPv4 addresses. In this case, for example, an IPv6 address specifying the broadcast processing server 6 is preferably registered in the communication device 2 in advance for the broadcast / multicast address of IPv4.
　上述の実施例では、受信パケットのＩＰアドレスに基づいてＩＰｖ６アドレスが生成されるが、第１の実施形態はこの方式に限定されるものではない。例えば、ＩＰｖ６アドレス生成部２２は、受信パケットのＩＰアドレスおよびポート番号に基づいてＩＰｖ６アドレスを生成してもよい。この場合、ＩＰｖ６アドレスの中に受信パケットのＩＰｖ４アドレスおよびポート番号が設定されてもよい。また、受信パケットのＩＰｖ４アドレスおよびポート番号の組合せに基づいてプレフィックスが検索されるようにしてもよい。 In the above-described embodiment, the IPv6 address is generated based on the IP address of the received packet, but the first embodiment is not limited to this method. For example, the IPv6 address generation unit 22 may generate an IPv6 address based on the IP address and port number of the received packet. In this case, the IPv4 address and port number of the received packet may be set in the IPv6 address. Also, the prefix may be searched based on the combination of the IPv4 address and port number of the received packet.
　図４～図５に示す実施例では、ＩＰｖ４パケットの送信元が属する論理ネットワークを識別する多重化ＩＤを利用してＩＰｖ６アドレスが生成されるが、第１の実施形態はこの方式に限定されるものではない。例えば、ＩＰｖ６アドレス生成部２２は、ＩＰｖ４アドレスおよびＶＰＮ番号に基づいてＩＰｖ６アドレスを生成してもよい。ＶＰＮ番号は、ＩＰｖ４パケットの送信元が属する仮想プライベートネットワークを識別する。この場合、ＩＰｖ６アドレスの中に受信パケットのＩＰｖ４アドレスおよびＶＰＮ番号が設定されてもよい。また、受信パケットのＩＰｖ４アドレスおよびＶＰＮ番号の組合せに基づいてプレフィックスが検索されるようにしてもよい。 In the embodiments shown in FIGS. 4 to 5, an IPv6 address is generated using a multiplexing ID for identifying the logical network to which the transmission source of the IPv4 packet belongs, but the first embodiment is limited to this method. It is not a thing. For example, the IPv6 address generation unit 22 may generate an IPv6 address based on the IPv4 address and the VPN number. The VPN number identifies the virtual private network to which the source of the IPv4 packet belongs. In this case, the IPv4 address and the VPN number of the received packet may be set in the IPv6 address. Also, the prefix may be searched based on the combination of the IPv4 address of the received packet and the VPN number.
　上述の実施例では、ブロードキャスト処理サーバ６がプロキシＡＲＰサーバであり、ＡＲＰ要求を含むＩＰｖ６パケットが通信装置２からブロードキャスト処理サーバ６にユニキャスト通信で転送されるが、第１の実施形態はこの方式に構成されるものではない。例えば、ブロードキャスト処理サーバ６がプロキシＢＯＯＴＰ（Bootstrap Protocol）サーバ、プロキシＤＨＣＰ（Dynamic Host Configuration Protocol）サーバ、プロキシＢＯＯＴＰリレーエージェント、またはプロキシＤＨＣＰリレーエージェントであってもよい。なお、ＢＯＯＴＰおよびＤＨＣＰは、ＩＰアドレスを取得する手順を含む。 In the above-described embodiment, the broadcast processing server 6 is a proxy ARP server, and an IPv6 packet including an ARP request is transferred from the communication apparatus 2 to the broadcast processing server 6 by unicast communication, but the first embodiment uses this method. It is not constructed. For example, the broadcast processing server 6 may be a proxy BOOTP (Bootstrap Protocol) server, a proxy DHCP (Dynamic Host Configuration Protocol) server, a proxy BOOTP relay agent, or a proxy DHCP relay agent. Note that BOOTP and DHCP include a procedure for acquiring an IP address.
　例えば、ＤＨＣＰでは、ＤＨＣＰクライアントは、ＩＰアドレスの割当てを要求するコマンドを複数のＤＨＣＰサーバにブロードキャストする。各ＤＨＣＰサーバは、ＤＨＣＰクライアントにＩＰアドレスを通知する。そして、ＤＨＣＰクライアントは、通知された複数のＩＰアドレスの中から使用すべきＩＰアドレスを選択する。 For example, in DHCP, a DHCP client broadcasts a command requesting assignment of an IP address to multiple DHCP servers. Each DHCP server notifies the DHCP client of an IP address. Then, the DHCP client selects an IP address to be used from among the notified plurality of IP addresses.
　ここで、ブロードキャスト処理サーバ６は、上述した複数のＤＨＣＰサーバのプロキシとして動作するものとする。この場合、ＤＨＣＰクライアント（例えば、図１に示すホスト３ａ）は、ＩＰアドレスの割当てを要求するコマンドを含むＩＰｖ４パケットを出力する。このＩＰｖ４パケットの宛先アドレスは、ブロードキャストアドレスである。そうすると、通信装置２ａは、このＩＰｖ４パケットをカプセル化してＩＰｖ６パケットを生成する。このＩＰｖ６パケットの宛先アドレスは、ブロードキャスト処理サーバ６を指定する。よって、ＩＰアドレスの割当てを要求するコマンドを含むＩＰｖ６パケットは、ユニキャスト通信により、ブロードキャスト処理サーバ６に転送される。 Here, the broadcast processing server 6 operates as a proxy for the plurality of DHCP servers described above. In this case, the DHCP client (for example, the host 3a shown in FIG. 1) outputs an IPv4 packet including a command requesting allocation of an IP address. The destination address of this IPv4 packet is a broadcast address. Then, the communication device 2a encapsulates this IPv4 packet to generate an IPv6 packet. The destination address of this IPv6 packet designates the broadcast processing server 6. Thus, an IPv6 packet including a command requesting allocation of an IP address is transferred to the broadcast processing server 6 by unicast communication.
　＜第２の実施形態＞
　第１の実施形態では、ブロードキャストまたはマルチキャストされるＩＰｖ４パケットが、ＩＰｖ６パケット内にカプセル化され、ユニキャスト通信でブロードキャスト処理サーバ６に転送される。これに対して第２の実施形態では、マルチキャストされるＩＰｖ６パケットが、ユニキャスト通信でブロードキャスト処理サーバ６に転送される。 Second Embodiment
In the first embodiment, IPv4 packets to be broadcasted or multicasted are encapsulated in IPv6 packets and forwarded to the broadcast processing server 6 in unicast communication. On the other hand, in the second embodiment, the IPv6 packet to be multicast is transferred to the broadcast processing server 6 by unicast communication.
　ＩＰｖ６パケットがマルチキャストされるプロトコルの一例は、ＮＤＰである。ＮＤＰは、ＡＲＰと同様に、ＩＰアドレスに対応するＭＡＣアドレスを解決する手順を含む。ＮＤＰにおけるＭＡＣアドレスの解決では、近隣要請（Neighbor Solicitation）メッセージがマルチキャストされる。そして、通信装置２は、近隣要請メッセージを含むマルチキャストＩＰｖ６パケットを受信すると、ユニキャスト通信で、そのＩＰｖ６パケットをブロードキャスト処理サーバ６に転送する。なお、ブロードキャスト処理サーバ６は、プロキシＮＤＰサーバとして動作するものとする。 An example of a protocol in which IPv6 packets are multicast is NDP. NDP, like ARP, includes a procedure to resolve the MAC address corresponding to the IP address. In resolution of a MAC address in NDP, a Neighbor Solicitation message is multicast. When the communication device 2 receives the multicast IPv6 packet including the proximity request message, the communication device 2 transfers the IPv6 packet to the broadcast processing server 6 by unicast communication. The broadcast processing server 6 operates as a proxy NDP server.
　例えば、図１に示す通信システム１００において、ＮＤＰの近隣要請メッセージを含むＩＰｖ６パケットがホスト３ｃから出力される。そうすると、このＩＰｖ６パケットは、ホスト３ｃに接続する通信装置２ｃにより受信される。このとき、このＩＰｖ６パケットの宛先ＩＰアドレスは、マルチキャストアドレスである。なお、ＩＰｖ６パケットのマルチキャストアドレスは、既知である。 For example, in the communication system 100 shown in FIG. 1, an IPv6 packet including an NDP neighbor solicitation message is output from the host 3c. Then, the IPv6 packet is received by the communication device 2c connected to the host 3c. At this time, the destination IP address of this IPv6 packet is a multicast address. The multicast address of the IPv6 packet is known.
　通信装置２ｃは、受信したＩＰｖ６パケットの宛先ＩＰアドレスがマルチキャストアドレスであることを検出する。そうすると、通信装置２ｃは、受信したＩＰｖ６パケットの先頭に、ブロードキャスト処理サーバ６を指定するＩＰｖ６アドレスを含むＩＰｖ６ヘッダを付加する。或いは、通信装置２ｃは、受信したＩＰｖ６パケットのヘッダを、ブロードキャスト処理サーバ６を指定するＩＰｖ６アドレスを含むＩＰｖ６ヘッダに置き換えてもよい。そして、通信装置２ｃは、このＩＰｖ６パケットをネットワーク１に出力する。この結果、ＮＤＰの近隣要請メッセージを含むＩＰｖ６パケットは、ユニキャスト通信でブロードキャスト処理サーバ６に転送される。なお、ブロードキャスト処理サーバ６は、プロキシＮＤＰサーバの処理を実行し、近隣要請メッセージに対応するＭＡＣアドレスをホスト３ｃに返送する。 The communication device 2c detects that the destination IP address of the received IPv6 packet is a multicast address. Then, the communication device 2c adds an IPv6 header including an IPv6 address specifying the broadcast processing server 6 to the beginning of the received IPv6 packet. Alternatively, the communication device 2c may replace the header of the received IPv6 packet with an IPv6 header including an IPv6 address specifying the broadcast processing server 6. Then, the communication device 2 c outputs the IPv6 packet to the network 1. As a result, the IPv6 packet including the NDP neighbor solicitation message is transferred to the broadcast processing server 6 by unicast communication. The broadcast processing server 6 executes the processing of the proxy NDP server, and sends back the MAC address corresponding to the proximity request message to the host 3c.
　このように、第２の実施形態では、ＩＰｖ６パケットの宛先アドレスがマルチキャストアドレスであるときは、通信装置２は、ＩＰｖ６パケットの宛先アドレスとして、ブロードキャスト処理サーバ６を指定するＩＰｖ６アドレスを生成する。よって、ＩＰｖ６マルチキャストパケットは、ＩＰｖ６のユニキャスト通知により、ブロードキャスト処理サーバ６に転送される。この結果、従来技術においてＩＰｖ６マルチキャストを含む手順が、マルチキャストを行うことなく実現され得る。換言すれば、運用が難しいマルチキャストルーティングプロトコルを使用することなく、アドレス解決等が実現される。 Thus, in the second embodiment, when the destination address of the IPv6 packet is a multicast address, the communication device 2 generates an IPv6 address specifying the broadcast processing server 6 as the destination address of the IPv6 packet. Therefore, the IPv6 multicast packet is transferred to the broadcast processing server 6 by the unicast notification of IPv6. As a result, a procedure including IPv6 multicast in the prior art can be realized without performing multicast. In other words, address resolution or the like is realized without using a multicast routing protocol which is difficult to operate.
　なお、通信装置２は、受信パケットの宛先ＩＰアドレスがマルチキャストアドレスかユニキャストアドレスかを判定し、その判定結果に応じてカプセル化を行うか否かを決定してもよい。この場合、受信パケットの宛先ＩＰアドレスがマルチキャストアドレスであれば、通信装置２は、ブロードキャスト処理サーバ６へのユニキャスト送信のためのカプセル化を実行する。一方、受信パケットの宛先ＩＰアドレスがユニキャストアドレスであれば、通信装置２は、そのパケットをカプセル化することなくネットワーク１に出力する。 The communication device 2 may determine whether the destination IP address of the received packet is a multicast address or a unicast address, and may determine whether to perform encapsulation according to the determination result. In this case, if the destination IP address of the received packet is a multicast address, the communication device 2 performs encapsulation for unicast transmission to the broadcast processing server 6. On the other hand, if the destination IP address of the received packet is a unicast address, the communication device 2 outputs the packet to the network 1 without encapsulating it.
　＜第３の実施形態＞
　第３の実施形態では、ブロードキャストアドレスまたはマルチキャストアドレスが設定されたＬ２フレームが、ＩＰｖ６パケット内にカプセル化され、ユニキャスト通信でブロードキャスト処理サーバ６に転送される。Ｌ２フレームは、特に限定されるものではないが、例えば、イーサネットフレームである。 Third Embodiment
In the third embodiment, an L2 frame in which a broadcast address or a multicast address is set is encapsulated in an IPv6 packet and transferred to the broadcast processing server 6 by unicast communication. The L2 frame is not particularly limited, and is, for example, an Ethernet frame.
　図７は、本発明の第３の実施形態に係る通信装置の機能の一例を示す。この例では、通信装置２は、Ｌ２フレームとＩＰｖ６パケットとの間でカプセル化を行う。 FIG. 7 shows an example of the function of the communication apparatus according to the third embodiment of the present invention. In this example, the communication device 2 performs encapsulation between the L2 frame and the IPv6 packet.
　第３の実施形態の通信装置２は、図７に示すように、ブリッジ部３１、カプセル化処理部３２、ＩＰｖ６ルータ部１３を備える。なお、通信装置２は、複数のブリッジ部３１を備えていてもよい。また、ＩＰｖ６ルータ部１３は、図２に示す第１の実施形態および図７に示す第３の実施形態において実質的に同じである。さらに、通信装置２は、図７に示していない他の機能を備えていてもよい。 The communication device 2 according to the third embodiment includes a bridge unit 31, an encapsulation processing unit 32, and an IPv6 router unit 13, as shown in FIG. The communication device 2 may include a plurality of bridge units 31. Also, the IPv6 router unit 13 is substantially the same in the first embodiment shown in FIG. 2 and the third embodiment shown in FIG. Furthermore, the communication device 2 may have other functions not shown in FIG.
　ブリッジ部３１は、ホストまたは他のＬ２ネットワークから受信するＬ２フレームを終端する。また、ブリッジ部３１は、ホストまたは他のＬ２ネットワークにＬ２フレームを送信する。 The bridge unit 31 terminates an L2 frame received from a host or another L2 network. The bridge unit 31 also transmits an L2 frame to the host or another L2 network.
　カプセル化処理部３２は、ブリッジ部３１により終端されたＬ２フレームをカプセル化してＩＰｖ６パケットを生成する。また、カプセル化処理部３２は、ＩＰｖ６ルータ部１３により終端されたＩＰｖ６パケットをデカプセル化してＬ２フレームを再生する。尚、カプセル化処理部３２の構成および動作については、後で詳しく説明する。 The encapsulation processing unit 32 encapsulates the L2 frame terminated by the bridge unit 31 to generate an IPv6 packet. Further, the encapsulation processing unit 32 decapsulates the IPv6 packet terminated by the IPv6 router unit 13 and regenerates the L2 frame. The configuration and operation of the encapsulation processing unit 32 will be described in detail later.
　図７に示す例では、通信装置２ｂは、ホスト３ｂにより生成されるＬ２フレームを終端し、カプセル化処理によりＩＰｖ６パケットを生成する。カプセル化は、例えば、図７に示すように、Ｌ２フレームにＩＰｖ６ヘッダを付加することにより実現される。 In the example illustrated in FIG. 7, the communication device 2b terminates the L2 frame generated by the host 3b, and generates an IPv6 packet by an encapsulation process. The encapsulation is realized, for example, by adding an IPv6 header to the L2 frame as shown in FIG.
　通信装置２ｂにより生成されたＩＰｖ６パケットは、ネットワーク１を介して、宛先装置に接続される通信装置２（ここでは、通信装置２ｆ）に転送される。そうすると、通信装置２ｆは、このＩＰｖ６パケットを終端し、デカプセル化処理によりＬ２フレームを再生する。デカプセル化は、図７に示すように、ＩＰｖ６パケットからＩＰｖ６ヘッダを削除することにより実現される。 The IPv6 packet generated by the communication device 2b is transferred via the network 1 to the communication device 2 (here, the communication device 2f) connected to the destination device. Then, the communication device 2 f terminates the IPv6 packet and reproduces the L2 frame by the decapsulation process. Decapsulation is realized by removing the IPv6 header from the IPv6 packet, as shown in FIG.
　図８は、第３の実施形態におけるカプセル化処理部３２の一例を示す。第３の実施形態では、カプセル化処理部３２は、図８に示すように、ＭＡＣアドレス抽出部４１、ＩＰｖ６アドレス生成部４２、多重化ＩＤ保持部４３、プレフィックステーブル４４、ＩＰｖ６パケット生成部４５、ＩＰｖ６ヘッダ削除部４６を備える。なお、カプセル化処理部３２は、図８に示していない他の機能を備えていてもよい。 FIG. 8 shows an example of the encapsulation processing unit 32 in the third embodiment. In the third embodiment, as shown in FIG. 8, the encapsulation processing unit 32 includes a MAC address extraction unit 41, an IPv6 address generation unit 42, a multiplexing ID holding unit 43, a prefix table 44, an IPv6 packet generation unit 45, An IPv6 header deletion unit 46 is provided. Note that the encapsulation processing unit 32 may have other functions not shown in FIG.
　ＭＡＣアドレス抽出部４１は、ブリッジ部３１により終端されたＬ２フレームのヘッダからＭＡＣアドレスを抽出する。 The MAC address extraction unit 41 extracts the MAC address from the header of the L2 frame terminated by the bridge unit 31.
　ＩＰｖ６アドレス生成部４２は、ＭＡＣアドレス抽出部４１により抽出されたＭＡＣアドレスに基づいて、ＩＰｖ６アドレスを生成する。このとき、Ｌ２フレームの宛先アドレスがブロードキャストアドレスまたはマルチキャストアドレスであったときには、ＩＰｖ６アドレス生成部４２は、ブロードキャスト処理サーバ６またはブロードキャスト処理サーバ６が属するネットワークを指定するＩＰｖ６アドレスを生成する。また、ＩＰｖ６アドレス生成部４２は、プレフィックステーブル４４に格納されているプレフィックスを利用してＩＰｖ６アドレスを生成してもよい。或いは、ＩＰｖ６アドレス生成部４２は、プレフィックステーブル４４に格納されているプレフィックスおよび多重化ＩＤ保持部４３に格納されている多重化ＩＤを利用してＩＰｖ６アドレスを生成してもよい。 The IPv6 address generation unit 42 generates an IPv6 address based on the MAC address extracted by the MAC address extraction unit 41. At this time, when the destination address of the L2 frame is a broadcast address or a multicast address, the IPv6 address generation unit 42 generates an IPv6 address specifying the broadcast processing server 6 or the network to which the broadcast processing server 6 belongs. Also, the IPv6 address generation unit 42 may generate an IPv6 address using the prefix stored in the prefix table 44. Alternatively, the IPv6 address generation unit 42 may generate an IPv6 address using the prefix stored in the prefix table 44 and the multiplexing ID stored in the multiplexing ID storage unit 43.
　多重化ＩＤ保持部４３は、図３に示す多重化ＩＤ保持部２３と実質的に同じである。すなわち、多重化ＩＤ保持部４３は、ネットワーク１上に構築される論理ネットワークを識別する多重化ＩＤを保持する。 The multiplexed ID holder 43 is substantially the same as the multiplexed ID holder 23 shown in FIG. That is, the multiplexing ID holding unit 43 holds the multiplexing ID for identifying the logical network constructed on the network 1.
　プレフィックステーブル４４は、図９に示すように、ＭＡＣアドレスおよび多重化ＩＤの組合せに対応するプレフィックスを格納する。図９に示す実施例では、ＭＡＣアドレス「pqrs」および多重化ＩＤ「01」の組合せに対応するプレフィックスとして「ホストｐｑｒｓが属するネットワークを表す値」が格納されている。また、ＭＡＣアドレス「pqrt」および多重化ＩＤ「01」の組合せに対応するプレフィックスとして「ホストｐｑｒｔが属するネットワークを表す値」が格納されている。さらに、ブロードキャスト（または、マルチキャスト）を指定するＭＡＣアドレスおよび多重化ＩＤ「01」の組合せに対応するプレフィックスとして「ブロードキャスト処理サーバ６が属するネットワークを表す値」が格納されている。 The prefix table 44 stores, as shown in FIG. 9, prefixes corresponding to combinations of MAC addresses and multiplexing IDs. In the embodiment shown in FIG. 9, “a value representing a network to which the host pqrs belongs” is stored as a prefix corresponding to the combination of the MAC address “pqrs” and the multiplexing ID “01”. Also, “a value representing a network to which the host pqrt belongs” is stored as a prefix corresponding to the combination of the MAC address “pqrt” and the multiplexing ID “01”. Furthermore, “a value representing a network to which the broadcast processing server 6 belongs” is stored as a prefix corresponding to the combination of the MAC address specifying broadcast (or multicast) and the multiplexing ID “01”.
　ＩＰｖ６パケット生成部４５は、ＩＰｖ６アドレス生成部４２により生成されるＩＰｖ６アドレスを用いてＩＰｖ６ヘッダを生成する。そして、ＩＰｖ６パケット生成部４５は、ブリッジ部３１により終端されたＬ２フレームに、生成したＩＰｖ６ヘッダを付加することでＩＰｖ６パケットを生成する。このＩＰｖ６パケットは、ＩＰｖ６ルータ部１３によりネットワーク１に出力される。 The IPv6 packet generation unit 45 generates an IPv6 header using the IPv6 address generated by the IPv6 address generation unit 42. Then, the IPv6 packet generation unit 45 generates an IPv6 packet by adding the generated IPv6 header to the L2 frame terminated by the bridge unit 31. The IPv6 packet is output to the network 1 by the IPv6 router unit 13.
　ＩＰｖ６ヘッダ削除部４６は、ＩＰｖ６ルータ部１３がネットワーク１から受信したＩＰｖ６パケットからＩＰｖ６ヘッダを削除する。即ち、ＩＰｖ６ヘッダ削除部４６は、受信ＩＰｖ６パケットに対してデカプセル化処理を実行する。この結果、Ｌ２フレームが再生される。再生されたＬ２フレームは、ブリッジ部３１により、宛先に転送される。 The IPv6 header deletion unit 46 deletes the IPv6 header from the IPv6 packet received by the IPv6 router unit 13 from the network 1. That is, the IPv6 header deleting unit 46 executes a decapsulation process on the received IPv6 packet. As a result, the L2 frame is reproduced. The reproduced L2 frame is transferred by the bridge unit 31 to the destination.
　図１０は、カプセル化処理におけるアドレス生成の一例を示す。この例では、ＩＰｖ６アドレスは、プレフィックス、多重化ＩＤ、ＭＡＣアドレスから構成される。多重化ＩＤは、多重化ＩＤ保持部４３に格納されている。ＭＡＣアドレスは、ＭＡＣアドレス抽出部４１により受信Ｌ２フレームから抽出される。プレフィックスは、多重化ＩＤおよびＭＡＣアドレスの組合せでプレフィックステーブル４４を検索することにより得られる。そして、ＩＰｖ６アドレス生成部４２は、プレフィックス、多重化ＩＤ、ＭＡＣアドレスを結合することでＩＰｖ６アドレスを生成する。 FIG. 10 shows an example of address generation in the encapsulation process. In this example, the IPv6 address is composed of a prefix, a multiplexing ID, and a MAC address. The multiplexing ID is stored in the multiplexing ID holding unit 43. The MAC address is extracted by the MAC address extraction unit 41 from the received L2 frame. The prefix is obtained by searching the prefix table 44 with a combination of multiplexing ID and MAC address. Then, the IPv6 address generation unit 42 generates an IPv6 address by combining the prefix, the multiplexing ID, and the MAC address.
　プレフィックスの長さは、多重化ＩＤのビット数に応じて決定される。例えば、ＩＰｖ６アドレスがプレフィックス、多重化ＩＤ、ＭＡＣアドレスのみから構成され、且つ、多重化ＩＤが８ビットである場合、プレフィックスの長さは、７２（＝１２８－８－４８）ビットである。 The length of the prefix is determined according to the number of bits of the multiplexing ID. For example, if the IPv6 address consists only of a prefix, a multiplexing ID, and a MAC address, and the multiplexing ID is 8 bits, the prefix length is 72 (= 128-8-48) bits.
　ネットワーク１は、第１の実施形態と同様に、ＩＰｖ６アドレスのプレフィックス領域の値に基づいてＩＰｖ６パケットを転送するものとする。ここで、第３の実施形態では、プレフィックスは、ＭＡＣアドレスに基づいて生成される。したがって、通信装置２からネットワーク１に出力されるＩＰｖ６パケットは、ＭＡＣアドレスにより識別される宛先装置が属するネットワークに転送される。 Similar to the first embodiment, the network 1 transfers an IPv6 packet based on the value of the prefix area of the IPv6 address. Here, in the third embodiment, the prefix is generated based on the MAC address. Therefore, the IPv6 packet output from the communication device 2 to the network 1 is transferred to the network to which the destination device identified by the MAC address belongs.
　受信Ｌ２フレームの宛先ＭＡＣアドレスがブロードキャストアドレスまたはマルチキャストアドレスであるときは、ＩＰｖ６アドレス生成部４２は、図９に示すプレフィックステーブル４４から「ブロードキャスト処理サーバ６が属するネットワークを表す値」を取得する。そして、このプレフィックス、多重化ＩＤ保持部４３から取得した多重化ＩＤ、および受信フレームから抽出した宛先ＭＡＣアドレス（即ち、ブロードキャストアドレスまたはマルチキャストアドレス）から宛先ＩＰｖ６アドレスが生成される。したがって、この場合、通信装置２からネットワーク１に出力されるＩＰｖ６パケットは、ブロードキャスト処理サーバ６が属するネットワークに転送される。すなわち、宛先ＭＡＣアドレスがブロードキャストアドレスまたはマルチキャストアドレスであるＬ２フレームが通信装置２に与えられたときは、そのＬ２フレームを含むＩＰｖ６パケットが生成され、そのＩＰｖ６パケットが通信装置２からブロードキャスト処理サーバ６にユニキャスト通信で転送される。 When the destination MAC address of the received L2 frame is a broadcast address or a multicast address, the IPv6 address generation unit 42 acquires “a value representing a network to which the broadcast processing server 6 belongs” from the prefix table 44 shown in FIG. Then, a destination IPv6 address is generated from the prefix, the multiplexing ID acquired from the multiplexing ID storage unit 43, and the destination MAC address (that is, the broadcast address or the multicast address) extracted from the received frame. Therefore, in this case, the IPv6 packet output from the communication device 2 to the network 1 is transferred to the network to which the broadcast processing server 6 belongs. That is, when an L2 frame whose destination MAC address is a broadcast address or a multicast address is given to the communication apparatus 2, an IPv6 packet including the L2 frame is generated, and the IPv6 packet is transmitted from the communication apparatus 2 to the broadcast processing server 6. It is transferred by unicast communication.
　なお、図１０に示す実施例では、ＭＡＣアドレスがＩＰｖ６アドレスの一部として使用されるが、第３の実施形態はこの方式に限定されるものではない。すなわち、ＩＰｖ６アドレス生成部４２により生成されるＩＰｖ６アドレスは、受信Ｌ２フレームのＭＡＣアドレスを含まなくてもよい。ただし、ＩＰｖ６アドレスは、ＭＡＣアドレスに基づいて生成される。この場合、例えば、ブロードキャストまたはマルチキャストを表すＭＡＣアドレスに対して、ブロードキャスト処理サーバ６を指定するＩＰｖ６アドレスが予め通信装置２に登録されていることが好ましい。 Although the MAC address is used as part of the IPv6 address in the example shown in FIG. 10, the third embodiment is not limited to this method. That is, the IPv6 address generated by the IPv6 address generation unit 42 may not include the MAC address of the received L2 frame. However, the IPv6 address is generated based on the MAC address. In this case, for example, an IPv6 address specifying the broadcast processing server 6 is preferably registered in the communication apparatus 2 in advance for the MAC address representing broadcast or multicast.
　また、第３の実施形態においても、ブロードキャスト処理サーバ６は、例えば、プロキシＡＲＰサーバ、プロキシＮＤＰサーバ、プロキシＢＯＯＴＰサーバ、プロキシＤＨＣＰサーバ、プロキシＢＯＯＴＰリレーエージェント、またはプロキシＤＨＣＰリレーエージェントである。 Also in the third embodiment, the broadcast processing server 6 is, for example, a proxy ARP server, a proxy NDP server, a proxy BOOTP server, a proxy DHCP server, a proxy BOOTP relay agent, or a proxy DHCP relay agent.
　＜ハードウェア構成＞
　通信装置２は、プロセッサ、メモリ、フレーム／パケットメモリ、インタフェース回路を備える。プロセッサは、メモリに格納されている通信制御プログラムを実行することにより、カプセル化処理部１２（ＩＰｖ４アドレス抽出部２１、ＩＰｖ６アドレス生成部２２、ＩＰｖ６パケット生成部２５、ＩＰｖ６ヘッダ削除部２６、ＭＡＣアドレス抽出部４１、ＩＰｖ６アドレス生成部４２、ＩＰｖ６パケット生成部４５、ＩＰｖ６ヘッダ削除部４６）の機能を提供する。なお、プロセッサは、ＤＳＰ（Digital Signal Processor）であってもよい。また、カプセル化処理部１２の機能の一部は、ハードウェア回路で実現してもよい。さらに、通信装置２に実装されるプロセッサおよび／またはメモリは、仮想化により実現してもよい。 <Hardware configuration>
The communication device 2 includes a processor, a memory, a frame / packet memory, and an interface circuit. The processor executes the communication control program stored in the memory to execute the encapsulation processing unit 12 (the IPv4 address extracting unit 21, the IPv6 address generating unit 22, the IPv6 packet generating unit 25, the IPv6 header deleting unit 26, the MAC address The functions of the extraction unit 41, the IPv6 address generation unit 42, the IPv6 packet generation unit 45, and the IPv6 header deletion unit 46) are provided. The processor may be a DSP (Digital Signal Processor). In addition, part of the functions of the encapsulation processing unit 12 may be realized by a hardware circuit. Furthermore, the processor and / or memory implemented in the communication device 2 may be realized by virtualization.
　メモリには、上述した通信制御プログラムが格納される。また、多重化ＩＤ保持部２３およびプレフィックステーブル２４（図７～図８に示す例では、多重化ＩＤ保持部４３およびプレフィックステーブル４４）もメモリに格納される。 The memory stores the communication control program described above. Further, the multiplexing ID holding unit 23 and the prefix table 24 (in the examples shown in FIGS. 7 to 8, the multiplexing ID holding unit 43 and the prefix table 44) are also stored in the memory.
　フレーム／パケットメモリは、ネットワークを介して受信したフレーム／パケットを一時的に格納する。また、フレーム／パケットメモリは、通信装置２により生成または再生されたフレーム／パケットを一時的に格納する。インタフェース回路は、ネットワークとのインタフェースを提供する。すなわち、インタフェース回路は、ネットワークを介して受信するフレーム／パケットを終端する。また、インタフェース回路は、フレーム／パケットをネットワークに出力する。 The frame / packet memory temporarily stores frames / packets received via the network. The frame / packet memory also temporarily stores the frame / packet generated or reproduced by the communication device 2. The interface circuit provides an interface with the network. That is, the interface circuit terminates frames / packets received via the network. The interface circuit also outputs frames / packets to the network.
１　ネットワーク
２（２ａ～２ｆ）　通信装置
６　ブロードキャスト処理サーバ
１２、３２　カプセル化処理部
２１　ＩＰｖ４アドレス抽出部
２２、４２　ＩＰｖ６アドレス生成部
２３、４３　多重化ＩＤ保持部
２４、４４　プレフィックステーブル
２５、４５　ＩＰｖ６パケット生成部
２６、４６　ＩＰｖ６ヘッダ削除部
４１　ＭＡＣアドレス抽出部 1 Network 2 (2a to 2f) Communication Device 6 Broadcast Processing Server 12, 32 Encapsulation Processing Unit 21 IPv4 Address Extraction Unit 22, 42 IPv6 Address Generation Unit 23, 43 Multiplexed ID Holding Unit 24, 44 Prefix Table 25, 45 IPv6 Packet generation unit 26, 46 IPv6 header deletion unit 41 MAC address extraction unit

Claims (9)

  1. 　第１のプロトコルに従って生成された第１のフレームから前記第１のフレームの宛先情報を抽出する抽出部と、
    　前記抽出部により抽出された宛先情報がブロードキャストアドレスまたはマルチキャストアドレスであるときに、予め決められた宛先を指定する、第２のプロトコルに従うユニキャストアドレスを、前記宛先情報に基づいて生成するアドレス生成部と、
    　前記アドレス生成部により生成されたユニキャストアドレスを含むヘッダ情報および前記第１のフレームに基づいて、前記第２のプロトコルに従う第２のフレームを生成するフレーム生成部と、
    　前記フレーム生成部により生成された第２のフレームを、前記第２のプロトコルに従うネットワークに出力する出力部と、
    　を備える通信装置。     An extraction unit that extracts destination information of the first frame from a first frame generated according to a first protocol;
    An address generation unit that generates a unicast address according to a second protocol that specifies a predetermined destination when the destination information extracted by the extraction unit is a broadcast address or a multicast address based on the destination information When,
    A frame generation unit that generates a second frame according to the second protocol based on header information including a unicast address generated by the address generation unit and the first frame;
    An output unit that outputs a second frame generated by the frame generation unit to a network according to the second protocol;
    A communication device comprising
  2. 　前記第１のプロトコルは、ＩＰｖ４、ＩＰｖ６、またはＭＡＣアドレスに基づいてフレームを転送するＯＳＩ参照モデルのレイヤ２プロトコルである
    　ことを特徴とする請求項１に記載の通信装置。     The communication apparatus according to claim 1, wherein the first protocol is a layer 2 protocol of an OSI reference model that transfers a frame based on IPv4, IPv6, or a MAC address.
  3. 　前記第２のプロトコルはＩＰｖ６である
    　ことを特徴とする請求項１または２に記載の通信装置。     The communication apparatus according to claim 1, wherein the second protocol is IPv6.
  4. 　前記第２のプロトコルに従うユニキャストアドレスは、前記抽出部により抽出された宛先情報を含む
    　ことを特徴とする請求項１に記載の通信装置。     The communication apparatus according to claim 1, wherein the unicast address according to the second protocol includes the destination information extracted by the extraction unit.
  5. 　前記抽出部により抽出された宛先情報がブロードキャストアドレスまたはマルチキャストアドレスであるときに前記アドレス生成部により生成される前記第２のプロトコルに従うユニキャストアドレスは、前記予め決められた宛先が属するネットワークを指定するプレフィックスおよび前記抽出部により抽出された宛先情報を含む
    　ことを特徴とする請求項１に記載の通信装置。     The unicast address according to the second protocol generated by the address generation unit when the destination information extracted by the extraction unit is a broadcast address or a multicast address designates a network to which the predetermined destination belongs. The communication apparatus according to claim 1, further comprising a prefix and destination information extracted by the extraction unit.
  6. 　前記第１のプロトコルのアドレスおよび前記第１のプロトコルによりサポートされる論理ネットワークを識別する識別子の組合せに対して、前記第２のプロトコルのアドレスのプレフィックスの値を格納するプレフィックス格納部をさらに備え、
    　前記アドレス生成部は、前記抽出部により抽出された宛先情報および前記第１のフレームの送信元が属する論理ネットワークを識別する識別情報の組合せで前記プレフィックス格納部を検索して対応するプレフィックスを取得する
    　ことを特徴とする請求項５に記載の通信装置。     It further comprises a prefix storage unit for storing the value of the prefix of the address of the second protocol with respect to the combination of the address of the first protocol and an identifier identifying a logical network supported by the first protocol,
    The address generation unit searches the prefix storage unit based on a combination of destination information extracted by the extraction unit and identification information identifying a logical network to which the transmission source of the first frame belongs, and acquires a corresponding prefix. The communication device according to claim 5, characterized in that:
  7. 　前記第１のフレームは、ＩＰｖ４アドレスに対応するＭＡＣアドレスの解決を要求するＡＲＰ（Address Resolution Protocol）要求を含むＩＰｖ４ブロードキャストパケットであり、
    　前記予め決められた宛先は、ＡＲＰ要求に応じてＭＡＣアドレスを解決するプロキシＡＲＰサーバである
    　ことを特徴とする請求項１に記載の通信装置。     The first frame is an IPv4 broadcast packet including an Address Resolution Protocol (ARP) request requesting resolution of a MAC address corresponding to an IPv4 address,
    The communication apparatus according to claim 1, wherein the predetermined destination is a proxy ARP server that resolves a MAC address in response to an ARP request.
  8. 　前記予め決められた宛先は、プロキシＡＲＰ（Address Resolution Protocol）サーバ、プロキシＮＤＰ（Neighbor Discovery Protocol）サーバ、プロキシＢＯＯＴＰ（Bootstrap Protocol）サーバ、またはプロキシＤＨＣＰ（Dynamic Host Configuration Protocol）サーバである
    　ことを特徴とする請求項１に記載の通信装置。     The predetermined destination is a proxy ARP (Address Resolution Protocol) server, a proxy NDP (Neighbor Discovery Protocol) server, a proxy BOOTP (Bootstrap Protocol) server, or a proxy DHCP (Dynamic Host Configuration Protocol) server. The communication device according to claim 1.
  9. 　第１のプロトコルに従って生成された第１のフレームから前記第１のフレームの宛先情報を抽出し、
    　前記第１のフレームから抽出された宛先情報がブロードキャストアドレスまたはマルチキャストアドレスであるときに、予め決められた宛先を指定する、第２のプロトコルに従うユニキャストアドレスを、前記宛先情報に基づいて生成し、
    　前記ユニキャストアドレスを含むヘッダ情報および前記第１のフレームに基づいて、前記第２のプロトコルに従う第２のフレームを生成し、
    　前記第２のプロトコルに従うネットワークに前記第２のフレームを出力する
    　ことを特徴とする通信方法。     Extracting destination information of the first frame from a first frame generated according to a first protocol;
    And generating a unicast address conforming to a second protocol, which designates a predetermined destination when the destination information extracted from the first frame is a broadcast address or a multicast address, based on the destination information.
    Generating a second frame according to the second protocol based on header information including the unicast address and the first frame;
    Outputting the second frame to a network according to the second protocol.
PCT/JP2017/046126 2017-12-22 2017-12-22 Communication device and communication method WO2019123630A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001285357A (en) * 2000-04-03 2001-10-12 Hitachi Ltd Communication system of multicast
JP2004260317A (en) * 2003-02-24 2004-09-16 Nippon Telegr & Teleph Corp <Ntt> Mobile ip multicast method, home agent, mobility anchor point, and mobile ip multicast program
JP2013514046A (en) * 2010-05-28 2013-04-22 ホアウェイ・テクノロジーズ・カンパニー・リミテッド Virtual layer 2 and mechanisms for making it scalable
JP2016146566A (en) * 2015-02-09 2016-08-12 日本電信電話株式会社 Network system and data transfer method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001285357A (en) * 2000-04-03 2001-10-12 Hitachi Ltd Communication system of multicast
JP2004260317A (en) * 2003-02-24 2004-09-16 Nippon Telegr & Teleph Corp <Ntt> Mobile ip multicast method, home agent, mobility anchor point, and mobile ip multicast program
JP2013514046A (en) * 2010-05-28 2013-04-22 ホアウェイ・テクノロジーズ・カンパニー・リミテッド Virtual layer 2 and mechanisms for making it scalable
JP2016146566A (en) * 2015-02-09 2016-08-12 日本電信電話株式会社 Network system and data transfer method

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