JP2014212398A - Communication system, communication node, packet processing method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve superiority in terms of a processing speed for specific processing, equipment costs, and load of a control device in a centralized control network.SOLUTION: A communication system includes a first communication node not having a prescribed packet processing function, a second communication node having the prescribed packet processing function, and a control device which instructs at least the first communication node to process a packet using the prescribed packet processing function. The first communication node has information for the second communication node having the prescribed packet processing function. When it receives an instruction to process the packet using the prescribed packet processing function from the control device, the first communication node requests the second communication node to process the packet using the prescribed packet processing function.

Description

  The present invention relates to a communication system, a communication node, a packet processing method, and a program, and more particularly, to a communication system, a communication node, a packet processing method, and a program in which a control device that controls the behavior of the communication node is arranged.

  Along with the development of IT (Information Technology) technology and the improvement of computer processing capability, the broadband and high performance of communication networks that serve as a data transmission / reception platform between computer resources are being promoted rapidly.

  As a data transmission / reception means in this communication network, a packet switching model has become the mainstream from the circuit switching model in the past. In the packet switching model, the network device reads the header part of the received packet and determines switching and routing information based on the rules specified in advance for the device and information exchanged between the transfer devices using a standardized protocol. In the mainstream, packet forwarding and header information rewriting are implemented.

  Under such circumstances, as a new trend, a method (centralized control type network) that implements packet transfer conditions and rewrite / transfer rules according to a centralized instruction from a separately installed central control device is proposed instead of the previous method. Has been. In this method, network traffic control is centrally managed by a central control unit. This facilitates dynamic change, monitoring and management of traffic control by the central control side software, and when developing software that performs advanced network control by performing traffic control by the central software. However, it has the merit that it becomes easy.

  As a typical example of the centralized control network, there is a network using the open flow described in Non-Patent Documents 1 and 2.

  In Patent Document 1, when a packet including a processing rule sequence configured by arranging processing rules (flow entries) sent from the central control device of the centralized control network is received, A communication node having a function of extracting a processing rule and setting it in its own device and then sending it to the next communication node is disclosed. In Patent Document 1, when a packet including a processing rule sequence configured by arranging processing rules (flow entries) sent from the central control device is received, the processing rule of the own device is extracted from the processing rule sequence. A communication node having a function of sending to the next communication node after setting to the self-device is disclosed.

  In Patent Document 2, in an environment where a first node such as a switching hub and a second node controlled by the central control device of the centralized control network are mixed, by rewriting the address information of the packet header, A configuration is disclosed in which a packet is made to reach from the second node on the entrance side to the second node on the exit side.

  Patent Document 3 discloses a packet transfer control that allows a user to provide a service that does not depend on the processing capability of a terminal while realizing processing in units of flows, and can perform flexible routing control based on a service control request. A method is disclosed.

International Publication No. 2011/115168 International Publication No. 2012/023604 JP 2005-57356 A

Nick McKeown and 7 others, “OpenFlow: Enabling Innovation in Campus Networks”, [online], [March 25, 2013 search], Internet <URL: http://www.openflow.org/documents/ openflow-wp-latest.pdf> “OpenFlow Switch Specification” Version 1.0.0. (Wire Protocol 0x01), [online], [March 25, 2013 search], Internet <URL: https://www.opennetworking.org/images/stories/downloads/specification/openflow-spec- v1.0.0.pdf>

  The following analysis is given by the present invention. Many network devices such as the OpenFlow switches of Non-Patent Documents 1 and 2 above execute rewrite processing for the MAC (Media Access Control) address described in the data link layer by using a mounted hardware chip. It is possible. On the other hand, in these devices, rewriting of network layer and transport layer addresses and port information constituting higher layers is handled by software processing. Software processing is generally slower in processing speed than hardware processing. Therefore, when rewriting of network layer and transport layer addresses and port information is required, it is necessary to suppress a decrease in processing speed in the entire network system.

  Of course, there are devices and chips that allow hardware rewriting of such high-level data, but they are relatively expensive. There may be a model in which a dedicated device capable of hardware rewriting processing of these higher layers is placed in a part of the network system, and only traffic that requires such rewriting is transmitted via the dedicated device. However, in this case, the control device determines whether it is necessary to rewrite the address and port information of the network layer and the transport layer for each flow, and performs control so that the corresponding packet passes through these dedicated devices. This will increase the load on the control device.

  In the centralized control type network, the present invention is from the viewpoint of processing speed, equipment cost and control device load for dealing with specific processing represented by rewriting of network layer and transport layer addresses and port information. It is an object of the present invention to provide a communication system, a communication node, a packet processing method, and a program that improve the superiority of the above.

  According to a first aspect, the first communication node that does not have a predetermined packet processing function, the second communication node that has the predetermined packet processing function, and at least the first communication node A control device for instructing packet processing using the packet processing function of the first communication node, wherein the first communication node has information on a second communication node having the predetermined packet processing function, and from the control device When a packet processing instruction using the predetermined packet processing function is received, a communication system is provided that requests the second communication node to perform packet processing using the predetermined packet processing function.

  According to a second aspect, the first communication node having no predetermined packet processing function, the second communication node having the predetermined packet processing function, and at least the first communication node And a control device for instructing packet processing using the packet processing function of the second communication node having information on a second communication node having the predetermined packet processing function. When a packet processing instruction using the packet processing function is received, a communication node is provided that requests the second communication node to perform packet processing using the predetermined packet processing function.

  According to a third aspect, for the first communication node that does not have a predetermined packet processing function, the second communication node that has the predetermined packet processing function, and at least the first communication node, the predetermined communication And a control device that instructs packet processing using the packet processing function of the first communication node of the communication system including the packet processing function, receiving a packet processing instruction using the predetermined packet processing function from the control device And requesting packet processing using the predetermined packet processing function to the second communication node based on information of the second communication node having the predetermined packet processing function. A method is provided. The method is associated with a specific machine, a communication node that operates according to instructions from the control device.

  According to a fourth aspect, for the first communication node not having a predetermined packet processing function, the second communication node having the predetermined packet processing function, and at least the first communication node, the predetermined communication And a control device for instructing packet processing using the packet processing function of the first communication node of the communication system including the packet processing function using the predetermined packet processing function from the control device. And a process of requesting the second communication node to perform packet processing using the predetermined packet processing function based on information of the second communication node having the predetermined packet processing function. Are provided. This program can be recorded on a computer-readable (non-transient) storage medium. That is, the present invention can be embodied as a computer program product.

  According to the present invention, in the centralized control type network, the processing speed, equipment cost, and control device load for dealing with specific processing represented by rewriting of network layer and transport layer addresses and port information are reduced. It is possible to improve the superiority from the viewpoint.

It is a figure which shows the structure of one Embodiment of this invention. It is a figure for demonstrating operation | movement of one Embodiment of this invention. It is a figure for demonstrating operation | movement of one Embodiment of this invention. It is a figure for demonstrating operation | movement of one Embodiment of this invention. It is a figure which shows the structure of the communication system of the 1st Embodiment of this invention. It is a block diagram which shows the detailed structure of the control apparatus and transfer apparatus of the 1st Embodiment of this invention. It is a block diagram which shows the detailed structure of the transfer apparatus with a header rewriting function of the 1st Embodiment of this invention. It is a figure which shows the capability information of the transfer apparatus of the 1st Embodiment of this invention, and a transfer apparatus with a header rewriting function. It is a figure which shows an example of the header rewriting content hold | maintained at the control policy memory | storage part of the control apparatus of the 1st Embodiment of this invention. It is a figure which shows the packet transfer path | route calculated by the control apparatus of the 1st Embodiment of this invention. It is an example of the flow entry which the control apparatus of the 1st Embodiment of this invention transmits to the transfer apparatus on a path | route. It is an example of the flow entry which the transfer apparatus 100 on the path | route of the 1st Embodiment of this invention hold | maintains, and the flow entry transferred to the transfer apparatus 150. It is a figure which shows the packet transfer path | route implement | achieved by the flow entry of FIG. It is an example of the flow entry which the transfer apparatus 100 on the path | route of the 2nd Embodiment of this invention hold | maintains, and the flow entry transferred to the transfer apparatus 150. It is a figure which shows the packet transmission path | route implement | achieved by the 2nd Embodiment of this invention. It is a block diagram which shows the detailed structure of the control apparatus and transfer apparatus of the 3rd Embodiment of this invention. It is a block diagram which shows the detailed structure of the control apparatus and transfer apparatus of the 4th Embodiment of this invention. It is a figure which shows the example of the packet transfer path | route when the transfer apparatus of the 4th Embodiment of this invention requests header rewriting to another transfer apparatus with a header rewriting function. It is a figure which shows the structure of the communication system of the 5th Embodiment of this invention.

  First, an outline of an embodiment of the present invention will be described with reference to the drawings. Note that the reference numerals of the drawings attached to this summary are attached to the respective elements for convenience as an example for facilitating understanding, and are not intended to limit the present invention to the illustrated embodiment.

  In one embodiment of the present invention, as shown in FIG. 1, the first communication node 100A having no predetermined packet processing function, the second communication node 150A having the predetermined packet processing function, and at least This can be realized by a configuration including a control device 300A that instructs the first communication node 100A to perform packet processing using the predetermined packet processing function.

  More specifically, the first communication node 100A has information of the second communication node 150A having the predetermined packet processing function, and a packet using the predetermined packet processing function is received from the control device 300A. When a processing instruction is received (see FIG. 2), the second communication node 150A is requested to perform packet processing using the predetermined packet processing function (see FIG. 3).

  For example, as shown in FIG. 2, it is assumed that the control device 300A transfers a packet addressed to the terminal B from the terminal A and instructs to rewrite the header. Upon receiving the instruction, the communication node 100A requests the second communication node 150A to rewrite the header of the packet addressed to the terminal B from the terminal A, as shown in FIG.

  By doing so, the communication node 100A can rewrite the header of the packet addressed to the terminal B from the terminal A and transfer it to the terminal B as shown in FIG. In performing the instruction, the control device 300A does not need to check whether the communication node 100A has a header rewriting function or to calculate a route through the communication node having the header rewriting function. . For this reason, it is possible to reduce the load on the control device 300A.

[First Embodiment]
Next, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 5 is a diagram showing a configuration of the communication system according to the first exemplary embodiment of the present invention. Referring to FIG. 5, a network 10 including transfer devices 100 to 120 arranged between terminals A and B 400 and transfer devices 150 and 160 with header rewriting function connected to the transfer devices 100 to 120, respectively, A configuration including a control device 300 that controls the above is shown. Note that the symbol “Pn” in the vicinity of the link end point between the transfer apparatuses 100 to 120 and the transfer apparatuses 150 and 160 with the header rewriting function in FIG. 5 represents the port numbers of these apparatuses.

  The transfer devices 100 to 120 process the received packet according to the control information transmitted from the control device 300. In this embodiment, it is assumed that the transfer apparatuses 100 to 120 are switches that can operate as the open flow switches of Non-Patent Documents 1 and 2. The transfer apparatuses 100 to 120 have a function of changing a MAC (Media Access Control) address in a packet header, but an IP (Internet Protocol) address, a TCP / UDP (Transmission Control Protocol / User Datagram Protocol) port, and the like. It is assumed that no change function is provided. Therefore, the transfer apparatuses 100 to 120 correspond to the first communication node that does not have the predetermined packet processing function.

  On the other hand, the transfer devices with header rewriting function 150 and 160 have a function of changing the MAC address, IP address, TCP / UDP port, and the like in the packet header, and a packet transfer function. Accordingly, the transfer devices with header rewriting function 150 and 160 correspond to the second communication node having the predetermined packet processing function described above. The transfer devices 150 and 160 with the header rewriting function may be switches that can operate as the open flow switches of Non-Patent Documents 1 and 2.

  The control apparatus 300 transmits to the transfer apparatuses 100 to 120 control information that defines a matching condition that is matched with the received packet and a processing content that is applied to a packet that matches the match condition. Control ~ 120. When the transfer devices 150 and 160 with the header rewriting function are switches that can operate as the open flow switches of Non-Patent Documents 1 and 2, the control device 300 controls the transfer devices 150 and 160 with the header rewriting function. Control information may be transmitted.

  FIG. 6 is a block diagram showing a detailed configuration of the control device 300 and the transfer devices 100 to 120. Referring to FIG. 6, the control device 300 includes a control policy storage unit 301, a flow entry generation unit 302, and a control message transmission / reception unit 303.

  The control policy storage unit 301 stores a control policy for determining a packet transfer route and header rewriting content. The control policy is input from a management terminal (not shown) by a network administrator or the like.

  The flow entry generation unit 302 calculates the packet transfer path on the network by referring to the control policy when receiving a packet from the transfer apparatuses 100 to 120, changing the topology of the network 10, and the like. The flow entry (control information) to be set in the transfer apparatuses 100 to 120 is generated.

  The control message transmission / reception unit 303 transmits a control message to the transfer apparatuses 100 to 120 and sets the flow entry generated by the flow entry generation unit 302. Further, the control message transmission / reception unit 303 notifies the transfer devices 100 to 120 that a control message (corresponding to the Packet-In message in Non-Patent Document 2) or the change of topology has occurred, notifying the occurrence of new communication. An operation of receiving the message and notifying the flow entry generation unit 302 is performed.

  As the control device 300 as described above, the open flow controllers of Non-Patent Documents 1 and 2 can be used.

  Subsequently, the transfer apparatuses 100 to 120 according to the present embodiment will be described. Referring to FIG. 6, the transfer devices 100 to 120 include a control message transmission / reception unit 101, a packet reception unit 102, a packet processing unit 103, a packet transmission unit 104, a flow entry modification unit 105, and a device selection unit 106. The flow entry storage unit 107 and the capability information exchange unit 108 are provided.

  When the control message transmission / reception unit 101 receives a control message instructing setting of a flow entry from the control device 300, the control message transmission / reception unit 101 sends the received flow entry to the flow entry modification unit 105. Further, when receiving a transmission request for notification of occurrence of new communication (corresponding to the Packet-In message in Non-Patent Document 2) from the packet processing unit 103, the control message transmission / reception unit 101 sends a new communication to the control device 300. A control message for notifying the occurrence (corresponding to the Packet-In message of Non-Patent Document 2) is transmitted.

  The packet receiving unit 102 transfers a packet received from the terminal 400 or another transfer device to the packet processing unit 103.

  The packet processing unit 103 searches the flow entry (control information) stored in the flow entry storage unit 107 for a flow entry (control information) having a matching condition that matches the packet received from the terminal 400 or another transfer device. Then, the processing content defined in the flow entry (control information) is applied to the received packet.

  The packet transmission unit 104 transmits a packet or a flow entry from a designated port according to an instruction from the packet processing unit 103 or the device selection unit 106.

  The flow entry modification unit 105 checks whether or not the processing content defined in the flow entry (control information) received from the control message transmission / reception unit 101 is content that cannot be performed by the own device. As a result of the confirmation, when the processing contents defined in the flow entry (control information) can be performed by the own device, the flow entry modification unit 105 stores the flow entry (control information) received from the control message transmission / reception unit 101 in the flow entry storage. Stored in the unit 107. On the other hand, when the processing content defined in the flow entry (control information) is content that cannot be executed by the own device, the flow entry correction unit 105 changes the processing content defined in the flow entry to content that can be executed by the own device. At the same time, the flow selection (control information) specifying the target packet and requested processing content is sent to the device selection unit 106, and the transfer devices with header rewriting function 150 and 160 requesting the processing content that cannot be performed by the own device. Request selection. When the flow entry modification unit 105 receives the selection result of the transfer devices with header rewriting function 150 and 160 from the device selection unit 106, the flow entry modification unit 105 sets the packet output destination of the modified flow entry as the transfer device with header rewriting function 150, Rewrite to 160.

  When the device selection unit 106 receives a selection request from the flow entry modification unit 105 for the transfer devices 150 and 160 with header rewriting function that requests processing contents that cannot be performed by the own device, the device selection unit 106 holds the request. With reference to the capability information table, the transfer devices with header rewriting function 150 and 160 that request processing contents that cannot be performed by the own device are selected and the flow entry correction unit 105 is answered. Further, the device selection unit 106 requests the packet transmission unit 104 to transmit a request for processing contents to the selected transfer devices with header rewriting function 150 and 160. In the present embodiment, a request for processing content to the selected transfer devices with header rewriting function 150 and 160 is made by transmitting the flow entry received from the flow entry modification unit 105.

  The flow entry storage unit 107 holds the flow entry received from the control device 300. The flow entry held in the flow entry storage unit 107 is updated by the flow entry correction unit 105 as necessary.

  The capability information exchanging unit 108 receives and stores capability information (see FIG. 8) from other transfer devices including the transfer devices with header rewriting function 150 and 160. The capability information exchanging unit 108 informs other transfer devices that the own device does not have a function of changing the IP address, TCP / UDP port, etc., so that the capability information of the own device is transferred to another transfer device or a header rewriting function. Send to attached transfer device. As a mechanism for exchanging capability information, an existing protocol such as LLDP (Link Layer Discovery Protocol) can be extended and used.

  The transfer devices 100 to 120 as described above are based on the OpenFlow switches of Non-Patent Documents 1 and 2, and by adding functions corresponding to the flow entry correction unit 105, the device selection unit 106, and the capability information exchange unit 108. Can be configured.

  Next, the configuration of the transfer devices with header rewriting function 150 and 160 according to this embodiment will be described. FIG. 7 is a block diagram showing a detailed configuration of the transfer device with a header rewriting function of the present embodiment. Referring to FIG. 7, transfer devices 150 to 160 with a header rewriting function include a control message transmission / reception unit 111, a packet reception unit 102, a packet processing unit 109, a packet transmission unit 104, a flow entry storage unit 107, and a capability. And an information exchange unit 108.

  Further, when receiving a control message instructing setting of a flow entry from the control device 300 or the control devices 100 to 120, the control message transmission / reception unit 111 stores the received flow entry in the flow entry storage unit 107.

  The other processing units are the same as those of the transfer devices 100 to 120 except that the packet processing unit 109 has a function of changing the IP address, TCP / UDP port, and the like.

  The transfer devices 150 and 160 with the header rewriting function as described above are sent from the transfer devices 100 to 120 to the OpenFlow switches of Non-Patent Documents 1 and 2 having the function of changing the IP address and the TCP / UDP port. It can be configured by adding a function that responds to a request for processing contents or a function that accepts a flow entry.

  Each unit (processing means) of the control device, transfer device, and transfer device with header rewriting function 150 and 160 shown in FIG. 6 and FIG. 7 uses the hardware of the computer that constitutes these devices. It can also be realized by a computer program that executes each process.

  Next, the operation of this embodiment will be described in detail with reference to the drawings. In the following description, among the headers of packets input to and output from the network 10, a header for storing a transmission / reception MAC address is a first header 601, a second header 602 for storing a transmission / reception IP address, and TCP port information is stored. This is referred to as a third header 603.

  In the following description, as illustrated in FIG. 8, the transfer devices 100 to 120 have a rewrite function of the first header 601, and the transfer devices with header rewrite function 150 and 160 have the first to third functions. Assume that the headers 601 to 603 have a rewriting function. The capability information table shown in FIG. 8 is exchanged in advance by the capability information exchanging unit 108 of the transfer devices 100 to 120 and the transfer devices with header rewriting function 150 and 160.

  In the following description, it is assumed that the control policy storage unit 301 of the control device 300 stores a control policy for rewriting the header of a packet flowing in the network as shown in FIG. In the example of FIG. 9, among the packets that have flowed into the network 10, the packet having the first header 601 of “30001”, the second header 602 of “32001”, and the third header 603 of “34001” A control policy is defined in which the first to third headers 601 to 603 are rewritten to “40001”, “42001”, and “44001”, respectively. Note that “30001” to “34001” and “40001” to “44001” are specific values stored in each header (for example, the MAC address, IP address, and TCP port of terminal A and terminal B in FIGS. 5 and 10). The number is an abstract representation of the number.

  By performing header rewriting as shown in FIG. 9, it becomes possible to transfer a packet in which an individual specific address is set through a preset route (for example, between the transfer device 100 and the transfer device 110). (There is an advantage that the setting of the flow entry (control information) to the other transfer devices arranged in the network can be omitted.) Of course, the header restoration processing may be performed by the transfer device on the exit side as necessary.

  Here, for example, when the notification of occurrence of new communication is received from the transfer apparatus 100 (corresponding to the Packet-In message in Non-Patent Document 2) or the topology change is detected, the control apparatus 300 as shown in FIG. Suppose that a route for transferring a packet addressed to terminal B from terminal A to terminal B via transfer apparatus 100 and transfer apparatus 110 is calculated.

  The control device 300 generates flow entries (control information) to be set in the transfer device 100 and the transfer device 110 based on the control policy shown in FIG. 9 and the route shown in FIG. Send. FIG. 11 is an example of a flow entry (control information) generated based on the control policy of FIG. 9 and the route of FIG.

  The flow entry (control information) in the upper part of FIG. 11 indicates a flow entry (control information) set in the transfer apparatus 100. The flow entry (control information) is input from the port P1, and the first to third headers 601 to 603 are “ When the packets of “30001”, “32001”, and “34001” are received, the first to third headers 601 to 603 are rewritten to “40001”, “42001”, and “44001”, respectively, and then the port P3 It is instructed to output from. By setting such a flow entry (control information), the control device 300 rewrites the header to the transfer device 100 and transfers the packet addressed from the terminal A to the terminal B along the designated route. Instruct.

  The flow entry (control information) in the lower part of FIG. 11 indicates a flow entry (control information) set in the transfer apparatus 110. The flow entry (control information) is input from the port P3, and the first to third headers 601 to 603 are “ When a packet of “40001”, “42001”, and “44001” is received, it is instructed to be output from the port P1. By setting such a flow entry (control information), the control device 300 instructs the transfer device 110 to transfer the packet addressed from the terminal A to the terminal B along the designated route.

  Next, operations of the transfer apparatuses 100 and 110 that have received the flow entry (control information) as described above will be described.

  As described above, the transfer apparatus 100 has a rewriting function for the first header 601 but does not have a rewriting function for the second header 602 and the third header 603 (see FIG. 8). Therefore, the flow entry modification unit 105 of the transfer apparatus 100 rewrites the flow entry (control information) in the upper part of FIG. 11 to the flow entry (control information) shown in the upper part of FIG. The first flow entry in the upper part of FIG. 12 is changed to one that does not rewrite the second header 602 and the third header 603 in the processing contents of the upper flow entry (control information) in FIG. Yes. Further, based on the selection result of the transfer device with the header rewriting function by the device selection unit 106 of the transfer device 100, the packet output destination is not the port P3 connected to the transfer device 110, but the transfer device 150 with the header rewriting function ( When the transfer device with header rewriting function 150 is selected), the port P5 is rewritten. The second flow entry in the upper part of FIG. 12 is the original packet instructed by the control device 300 for the packet in which the second header 602 and the third header 603 are rewritten by the transfer device 150 with the header rewriting function. This is a flow entry for transferring to the transfer device 110 that is the transfer destination.

  In addition, the transfer apparatus 100 requests the processing contents that cannot be performed by itself by transmitting the flow entry (control information) shown in the lower part of FIG. 12 to the selected transfer apparatus 150 with the header rewriting function. . In the example of the flow entry (control information) shown in the lower part of FIG. 12, the second header 602 and the third header 603 of the packet in which the first header 601 is rewritten by the transfer device 100 are rewritten, and then the transfer device 100 A flow entry (control information) instructing to return is sent. The transfer apparatus with header rewriting function 150 stores the flow entry (control information) shown in the lower part of FIG. 12 in the flow entry storage unit 107 (note that the output port P2 of the flow entry (control information) shown in the lower part of FIG. May be set on the transfer device 100 side, but may be set on the transfer device 150 side with the header rewriting function). For this reason, when the transfer apparatus 150 with the header rewriting function receives a packet addressed from the terminal A to the terminal B from the transfer apparatus 100, the transfer apparatus 150 rewrites the second header 602 and the third header 603 of the packet, and then transfers the packet. The operation of returning to the apparatus 100 is performed.

  On the other hand, the transfer apparatus 110 that has received the flow entry (control information) shown in the lower part of FIG. 11 has contents that can be executed by the own apparatus (no header rewriting). Control information) is stored in the flow entry storage unit 107. Therefore, when the transfer device 110 receives a packet addressed from the terminal A to the terminal B from the transfer device 100, the transfer device 110 performs an operation of transferring the packet from the port P1 to which the terminal B is connected.

  As described above, the processing content instructed by the flow entry (control information) from the control device 300 is rewritten according to the capability of the transfer device, and if necessary, the transfer device 150 with a header rewriting function, 160 is assigned. As a result, the packet addressed from the terminal A to the terminal B is sent along the route shown in FIG. 13, and necessary header rewriting is performed in the transfer device 150 with a header rewriting function. Strictly speaking, the header rewriting of the content instructed by the control device 300 is not performed in the transfer device 100, but the header rewriting of the content instructed by the control device 300 is faithfully executed as a whole. It will be.

  As described above, according to the present embodiment, the control device 300 can create a flow entry (control information) according to the control policy without considering the capability of each transfer device. Can be reduced. Further, since it is possible to perform necessary processing without providing all the transfer apparatuses with the header rewriting function of the upper layer, the introduction cost of the entire network can be reduced.

  The first embodiment can be suitably applied particularly to a large-scale NAT (Network Address Translation) processing system for converting a local IP address and a network IP address, which is found in Internet service providers and the like. When performing large-scale NAT processing in a centralized control network such as OpenFlow, there is a concern that the load on the control device (controller) may increase due to rewriting of the IP address or TCP / UDP port number. By adopting the configuration as in the first embodiment, the load can be reduced.

[Second Embodiment]
Subsequently, the transfer device with header rewriting function 150 requested to process the packet from the transfer device 100 sends the packet after the header rewrite to the transfer device 110 on the path instead of the transfer device 100 of the request source. The embodiment will be described. Since the present embodiment can be realized with a configuration substantially similar to that of the first embodiment, the following description will focus on the differences.

  14 shows the flow entry (control information) to be rewritten when the flow entry modification unit 105 of the transfer apparatus 100 of the present embodiment receives the upper flow entry (control information) in FIG. It is an example of the flow entry (control information) which shows the packet processing content transmitted to the transferred apparatus 150 with a header rewriting function.

  As shown in FIG. 14, the flow entry modification unit 105 of the present embodiment rewrites the second header 602 and the third header 603 in the processing contents of the upper flow entry (control information) in FIG. And the output destination is corrected to a flow entry (control information) with the header rewriting function-added transfer device 150 (when the header rewriting function-added transfer device 150 is selected) stored in the flow entry storage unit 107. .

  Further, the transfer apparatus 100 transmits the flow entry (control information) shown in the lower part of FIG. 14 to the selected transfer apparatus 150 with the header rewriting function, so that the process and the transfer destination that cannot be performed by the own apparatus are transferred. Request transfer of. In the example of the flow entry (control information) shown in the lower part of FIG. 14, the transfer apparatus 100 requests to rewrite the second header 602 and the third header 603 of the packet in which the first header 601 is rewritten. At the same time as the request, the transfer device 100 sends the switch ID (DatapathID) of the transfer device 110 that is the transfer destination to the transfer device 150 with the header rewriting function and the flow entry (control information) received from the control device 300 shown in the upper part of FIG. )

  The transfer device 150 with the header rewriting function analyzes the switch ID (DatapathID) of the transfer device 110 of the transfer destination designated by the transfer device 100 and the flow entry (control information) received from the control device 300 shown in the upper part of FIG. As a result, the port P3 that is the transfer destination of the packet after the header rewriting is set in the flow entry (control information). Of course, when the requesting transfer apparatus 100 knows which port of the transfer apparatus 150 with the header rewriting function is connected to the transfer apparatus 110, the output port P3 of the packet after rewriting on the transfer apparatus 100 side. May be set.

  According to the second embodiment as described above, as shown by the dotted line in FIG. 15, the transfer device on the path designated by the control device 300 without returning the packet after the header rewriting to the requesting transfer device 100. 110 can be directly transmitted.

[Third Embodiment]
Next, a description will be given of a third embodiment in which the control device 300 mediates the exchange of capability information between the transfer devices 100 to 120 and the transfer devices 150 and 160 with the header rewriting function. Since the present embodiment can be realized with a configuration substantially similar to that of the first embodiment, the following description will focus on the differences.

  FIG. 16 is a block diagram illustrating a detailed configuration of the control device and the transfer device according to the third embodiment of this invention. 6 is different from the configuration of the first embodiment shown in FIG. 6 in that the control device 300B includes a capability information relay unit 304, transfer devices 100B to 120B, and a transfer device with a header rewriting function (illustrated). The omitted capability information exchanging unit 108B exchanges capability information with the capability information relay unit 304 of the control device 300B via the control message transmitting / receiving unit.

  According to the present embodiment having the above-described configuration, the capability information exchange between the transfer apparatuses 100B to 120B and the transfer apparatus with a header rewriting function is facilitated. For example, by notifying the address of the transfer device with a header rewriting function together with the capability information of the control device 300B, it becomes possible to request packet processing to a transfer device with a header rewriting function that is distantly located.

[Fourth Embodiment]
Next, a description will be given of a fourth embodiment in which not only capability information but also load information of each device is exchanged between the transfer devices 100 to 120 and the transfer devices with header rewriting function 150 and 160. Since the present embodiment can be realized with a configuration substantially similar to that of the first embodiment, the following description will focus on the differences.

  FIG. 17 is a block diagram illustrating detailed configurations of a control device and a transfer device according to the fourth embodiment of this invention. 6 differs from the configuration of the first embodiment shown in FIG. 6 in that a capability information and load information exchanging unit 118 is provided instead of the capability information exchanging units of the transfer devices 100C to 120C. And the point that the device selection unit 116 selects a device that requests packet processing by referring to the additional information in addition to the capability information.

  For example, when selecting a transfer device with a header rewriting function that requests a certain packet process, the device selection unit 116 according to the present embodiment not only can perform the processing, but also the load of the transfer device with the header rewriting function to be selected. A transfer device with a header rewriting function is selected to check whether or not the value representing the state exceeds a predetermined value.

  According to the present embodiment having the above-described configuration, selection is performed in consideration of the load state of the transfer device with a header rewriting function, so that a situation where processing is concentrated on a specific transfer device with a header rewriting function is avoided. It becomes possible.

  For example, as shown in FIG. 18, when there are two transfer devices with a header rewriting function capable of executing a certain header rewriting process, the transfer device with a header rewriting function with a less concentrated load (for example, the header of FIG. 18). By selecting the transfer device with rewrite function 160), it becomes possible to distribute the load among the transfer devices with header rewrite function.

[Fifth Embodiment]
Next, a description will be given of a fifth embodiment in which processing contents requested by the transfer apparatuses 100 to 120 to the transfer apparatuses with header rewriting function 150 and 160 are changed. Since the present embodiment can be realized with a configuration substantially similar to that of the first embodiment, the following description will focus on the differences.

  In the first to fourth embodiments described above, the transfer apparatuses 100 to 120 have been described with an example in which the transfer apparatuses with the header rewriting function 150 and 160 request the packet header to be rewritten. The processing content requested to other devices is not limited to header rewriting. As shown in FIG. 19, in this embodiment, control message transmission devices 151 and 161 are arranged instead of the transfer devices 150 and 160 with header rewriting function. According to this configuration, the transfer apparatuses 100 to 120 can request the control apparatus 300 to notify the transfer apparatuses 150 and 160 with the header rewriting function that a new packet has arrived on the network.

  For example, when a packet that does not match any of the flow entries held in its own flow entry storage unit 107 arrives, the transfer apparatus 100 encapsulates the packet and sends it to the control apparatus 300 as shown in FIG. Send. Then, based on the encapsulated packet, the control device 300 calculates a packet transfer route and generates a flow entry, and sets it in each transfer device. Since a general OpenFlow switch consumes CPU resources and transmits a control message to the control device 300, as in the present embodiment, a device specialized for encapsulation processing (control message transmission devices 151 and 161). It is possible to reduce the load on the transfer apparatuses 100 to 120 and the control apparatus 300.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and further modifications, substitutions, and adjustments are possible without departing from the basic technical idea of the present invention. Can be added. For example, the network configuration and the configuration of elements shown in the drawings are examples for helping understanding of the present invention, and are not limited to the configurations shown in these drawings.

  For example, in the above-described embodiment, an example has been given in which the transfer devices 100 to 120 request other devices to rewrite the header. However, for example, a configuration in which other devices are requested to read and rewrite information in the payload portion is also employed. Is possible.

Finally, a preferred form of the invention is summarized.
[First embodiment]
(Refer to the communication system according to the first viewpoint)
[Second form]
In the communication system of the first form,
The control device sets, in the first communication node, control information that defines a matching condition that is matched with a received packet and a processing content that is applied to a packet that matches the matching condition. Instruct the packet processing using the processing function,
A communication system in which the first communication node requests the second communication node to perform packet processing using the predetermined packet processing function among the processing contents defined in the control information.
[Third embodiment]
In the communication system of the second form,
The first communication node transmits, to the second communication node, control information that defines a matching condition that is matched with a received packet and a processing content that is applied to a packet that matches the matching condition. A communication system that requests packet processing using the predetermined packet processing function by transmitting a packet to be processed to a second communication node.
[Fourth form]
In the communication system according to any one of the first to third aspects,
A plurality of the second communication nodes are arranged;
The first communication node and the second communication node exchange capability information regarding their packet processing functions,
The communication system wherein the first communication node selects a second communication node that requests packet processing using the predetermined packet processing function based on the exchanged capability information.
[Fifth embodiment]
In the communication system according to any one of the first to fourth aspects,
A communication system for exchanging the capability information via the control device.
[Sixth embodiment]
In the communication system according to any one of the first to fifth aspects,
A plurality of the second communication nodes are arranged;
Further, the first communication node and the second communication node exchange load information,
The communication system in which the first communication node selects a second communication node that requests packet processing using the predetermined packet processing function based on the exchanged load information.
[Seventh form]
In the communication system according to any one of the first to sixth aspects,
The communication system in which the packet processing using the predetermined packet processing function is a header rewriting or a payload rewriting process.
[Eighth form]
In the communication system according to any one of the first to seventh aspects,
The communication system, wherein the packet processing using the predetermined packet processing function is processing for transferring a received packet to the control device.
[Ninth Embodiment]
(Refer to the communication node from the second viewpoint)
[Tenth embodiment]
(Refer to the packet processing method from the third viewpoint)
[Eleventh form]
(Refer to the program from the fourth viewpoint above.)
Note that the ninth to eleventh forms can be expanded to the second to eighth forms as in the first form.

  Each disclosure of the above-mentioned patent document and non-patent document is incorporated herein by reference. Within the scope of the entire disclosure (including claims) of the present invention, the embodiments and examples can be changed and adjusted based on the basic technical concept. Further, various combinations or selections of various disclosed elements (including each element of each claim, each element of each embodiment or example, each element of each drawing, etc.) within the scope of the claims of the present invention. Is possible. That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the technical idea. In particular, with respect to the numerical ranges described in this document, any numerical value or small range included in the range should be construed as being specifically described even if there is no specific description.

DESCRIPTION OF SYMBOLS 10 Network 100-120, 100B-120B, 100C-120C Transfer apparatus 100A 1st communication node 101, 111 Control message transmission / reception part 102 Packet reception part 103, 109 Packet processing part 104 Packet transmission part 105 Flow entry correction part
106, 116 Device selection unit 107 Flow entry storage unit 108, 108B Capability information exchange unit 118 Capability information and load information exchange unit 150, 160 Transfer device with header rewriting function 151, 161 Control message transmission device 150A Second communication node 300, 300A, 300B Control device 301 Control policy storage unit 302 Flow entry generation unit 304 Capability information relay unit 303 Control message transmission / reception unit 400 Terminal

Claims (10)

A first communication node having no predetermined packet processing function; a second communication node having the predetermined packet processing function;
A control device that instructs packet processing using the predetermined packet processing function to at least the first communication node,
The first communication node has information of a second communication node having the predetermined packet processing function, and receives a packet processing instruction using the predetermined packet processing function from the control device, Requesting the second communication node to perform packet processing using the predetermined packet processing function;
A communication system characterized by the above. The control device sets, in the first communication node, control information that defines a matching condition that is matched with a received packet and a processing content that is applied to a packet that matches the matching condition. Instruct the packet processing using the processing function,
The communication system according to claim 1, wherein the first communication node requests the second communication node to perform packet processing using the predetermined packet processing function among the processing contents defined in the control information.   The first communication node transmits, to the second communication node, control information that defines a matching condition that is matched with a received packet and a processing content that is applied to a packet that matches the matching condition. The communication system according to claim 2, wherein a packet processing using the predetermined packet processing function is requested by transmitting a packet to be processed to a second communication node. A plurality of the second communication nodes are arranged;
The first communication node and the second communication node exchange capability information regarding their packet processing functions,
The communication system according to any one of claims 1 to 3, wherein the first communication node selects a second communication node that requests packet processing using the predetermined packet processing function based on the exchanged capability information. .   The communication system according to any one of claims 1 to 4, wherein the capability information is exchanged via the control device. A plurality of the second communication nodes are arranged;
Further, the first communication node and the second communication node exchange load information,
The communication system according to any one of claims 1 to 5, wherein the first communication node selects a second communication node that requests packet processing using the predetermined packet processing function based on the exchanged load information. .   The communication system according to any one of claims 1 to 6, wherein the packet processing using the predetermined packet processing function is rewriting of a header or rewriting of a payload portion.   The communication system according to any one of claims 1 to 7, wherein the packet processing using the predetermined packet processing function is a process of transferring a received packet to the control device. A first communication node not having a predetermined packet processing function, a second communication node having the predetermined packet processing function, and a packet using the predetermined packet processing function at least for the first communication node Connected to a communication system including a control device for instructing processing,
The second communication node having information on the second communication node having the predetermined packet processing function, and receiving a packet processing instruction using the predetermined packet processing function from the control device; A communication node that requests packet processing using the predetermined packet processing function. A first communication node having no predetermined packet processing function; a second communication node having the predetermined packet processing function;
The first communication node of the communication system including a control device that instructs packet processing using the predetermined packet processing function to at least the first communication node;
Receiving a packet processing instruction from the control device using the predetermined packet processing function;
Requesting packet processing using the predetermined packet processing function to the second communication node based on information of the second communication node having the predetermined packet processing function.

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