Communication system, control device, processing rule setting method, packet transmission method, and program

Abstract

A communication system comprises control devices, and forwarding nodes each includes packet processing unit that performs processing of a received packet based on a processing rule set in advance or received from control device associated with the node. First control device among the control devices, in response to a predetermined trigger, refers to correspondence between forwarding nodes and control devices, and transmits, among forwarding path information, at least forwarding path information that includes a forwarding node associated with the first control device, to second control device associated with a forwarding node that is not associated with first control device, among forwarding nodes on a forwarding path of the received packet. Second control device generates and sends the processing rule to a forwarding node on the forwarding path, among forwarding nodes associated with the second control device, based on the forwarding path information.

1 . A communication system, comprising a plurality of forwarding nodes and a plurality of control devices, wherein
 each of the plurality of forwarding nodes comprises a packet processing unit that performs processing of a received packet based on a processing rule set in advance or received from a control device associated with an own forwarding node, and   the plurality of control devices includes a first control device that comprises:   a correspondence management unit that stores correspondence between each of the plurality of forwarding nodes and each of the plurality of control devices; and   a path transmission unit that, in response to a predetermined trigger, refers to the correspondence between each of the plurality of forwarding nodes and each of the plurality of control devices, and transmits, among forwarding path information, forwarding path information that includes at least a forwarding node associated with the own first control device, to an other second control device associated with a forwarding node that is not associated with the own first control device, among forwarding nodes on a forwarding path of a received packet.   
     
     
         2 . The communication system according to  claim 1 , wherein each of the plurality of control devices further comprises:
 a database that stores a network topology describing connection among forwarding nodes including at least a forwarding node associated with the own control device;   a processing rule generation unit that, based on forwarding path information received from the path transmission unit, refers to the network topology and generates the processing rule for a forwarding node in a forwarding path of a received packet among forwarding nodes associated with the own control device; and   a transmission unit that transmits the generated processing rule to the forwarding node on the forwarding path of the received packet, among forwarding nodes associated with the own control device.   
     
     
         3 . The communication system according to  claim 1 , wherein the first control device comprising the path transmission unit further comprises:
 a database that stores a network topology describing connection among forwarding nodes including at least a forwarding node associated with the own first control device; and   a path calculation unit that, when receiving from a forwarding node connected to the own first control device a request to transmit a processing rule concerning a new packet, refers to the network topology and calculates a forwarding path.   
     
     
         4 . The communication system according to  claim 3 , wherein,
 with the first control device comprising the path calculation unit as a start point, a control device associated with a forwarding node(s) on the forwarding path forwards the new packet independently of transmission processing of a processing rule, and   a control device associated with a forwarding node at an end of the forwarding path transmits the new packet to the forwarding node at the end, and instructs the forwarding node at the end to output the new packet from a specified port.   
     
     
         5 . The communication system according to  claim 1 , wherein
 the forwarding path information includes a processing rule for transmission to a forwarding node that is not associated with the own first control device, and   a second control device that receives the forwarding path information transmits a processing rule included in the forwarding path information to a forwarding node associated with the own second control device, among forwarding nodes on a forwarding path of a received packet.   
     
     
         6 . The communication system according to  claim 1 , wherein the forwarding path is comprises a forwarding path calculated in advance for a combination of a start point node and an end point node that are arbitrarily selected. 
     
     
         7 . The communication system according to  claim 3 , wherein the forwarding path is cached for a predetermined time period, and calculation of a forwarding path is omitted when a combination of an identical start point node and end point node is cached. 
     
     
         8 . The communication system according to  claim 2 , wherein
 each of the plurality of control devices comprises: the path transmission unit and a path calculation unit that, when receiving from a forwarding node connected to the own control device a request to transmit a processing rule concerning a new packet, refers to the network topology and calculates a forwarding path;   the path transmission unit of a first control device transmits, to a second control device associated with a forwarding node that received a packet from a forwarding node on the forwarding path, connected to the own first control device the new packet and a start point for calculating a forwarding path for a forwarding node associated with the second control device, instead of the forwarding path information; and   the second control device that received the start point and the new packet recalculates a forwarding path based on the start point and the new packet, and generates and transmits a processing rule.   
     
     
         9 . The communication system according to  claim 1 , wherein
 the first control device comprises a data synchronization unit that obtains information of a plurality of forwarding nodes connected to the own first control device, and based on the obtained data updates   at least one of connection relationship of each of the plurality of forwarding nodes, and correspondence between each of the plurality of forwarding nodes and each of the plurality of control devices.   
     
     
         10 . A communication system, comprising a plurality of forwarding nodes and a plurality of control devices, wherein
 each of the plurality of forwarding nodes comprises a packet processing unit that performs processing of a received packet based on a processing rule set in advance or received from a control device associated with an own forwarding node;   each of the plurality of control devices comprises a correspondence management unit that stores correspondence between each of the plurality of forwarding nodes and each of the plurality of control devices;   when a received packet is forwarded from a certain forwarding node, a control device associated with any forwarding node(s) on a forwarding path refers to the correspondence between each of the plurality of forwarding nodes and each of the plurality of control devices, to transmit the received packet in turn; and   a control device associated with a forwarding node at an end of the forwarding path transmits the received packet to the forwarding node at the end, and instructs the forwarding node at the end to output the received packet from a specified port.   
     
     
         11 . A first control device, which is connected to a plurality of forwarding nodes,
 each of the plurality of the forwarding nodes comprising a packet processing unit that performs processing of a received packet based on a processing rule set in advance or received from a control device associated with a forwarding node(s), wherein   the first control device comprises:   a correspondence management unit that stores correspondence between each of a forwarding nodes group including the plurality of forwarding nodes and each of a plurality of control devices; and   a path transmission unit that, in response to a predetermined trigger, refers to the correspondence between each of the forwarding nodes and each of the plurality of control devices, and transmits, among forwarding path information, forwarding path information that includes at least a forwarding node associated with an own first control device, to an other second control device associated with a forwarding node that is not associated with the own first control device, among forwarding nodes on a forwarding path of a received packet.   
     
     
         12 . A processing rule setting method in a communication system comprising a plurality of control devices and a plurality of forwarding nodes each comprising a packet processing unit that performs processing of a received packet based on a processing rule set in advance or received from a control device associated with an own forwarding node, the processing rule setting method, comprising:
 by a first control device among the plurality of control devices, in response to a predetermined trigger, referring to correspondence between each of the plurality of forwarding nodes and each of the plurality of control devices, and transmitting, among forwarding path information, at least forwarding path information that includes a forwarding node associated with the own first control device, to a second control device associated with a forwarding node that is not associated with the first control device, among forwarding nodes on a forwarding path of the received packet; and   by the second control device that receives the forwarding path information, generating a processing rule by referring to network topology describing connection among forwarding nodes including at least a forwarding node associated with the second control device and transmitting the processing rule to a forwarding node on a forwarding path of a received packet, among forwarding nodes associated with the own second control device.   
     
     
         13 . A communication method being a method of transmitting a packet in a communication system comprising a plurality of control devices, and a plurality of forwarding nodes each comprising a packet processing unit that performs processing of a received packet based on a processing rule set in advance or received from a control device associated with an own forwarding node, the communication method comprising:
 by a control device associated with a forwarding node on a forwarding path, when a received packet is forwarded from a certain forwarding node, referring to a correspondence between each of the plurality of forwarding nodes and each of the plurality of control devices to transmit the received packet in turn, and   by a control device associated with a forwarding node at an end of the forwarding path, transmitting the received packet to the forwarding node at the end, and instructing the forwarding node at the end to output the received packet from a specified port.   
     
     
         14 . A computer-readable medium recorded thereon a program causing a computer making up a first control device, connected to a plurality of forwarding nodes each comprising a packet processing unit that performs processing of a received packet based on a processing rule set in advance or received from a control device associated with the own forwarding node, and which comprises a correspondence management unit that stores a correspondence between each of a forwarding nodes group including the plurality of forwarding nodes and each of a plurality of control devices, the program causing the computer to execute:
 in response to a predetermined trigger, generating and transmitting a processing rule to a forwarding node on a forwarding path of a received packet, among forwarding nodes associated with an own first control device; and   referring to a correspondence between each of the plurality of forwarding nodes and each of the plurality of control devices, and transmitting, among forwarding path information, forwarding path information that includes at least a forwarding node associated with the own first control device, to an other second control device associated with a forwarding node that is not associated with the own first control device, among forwarding nodes on the forwarding path of the received packet.