Communication system, switch, control apparatus, packet processing method, and program

1. A communication system, comprising:

a control apparatus that transmits, to a switch, 2 or more flow entries having an identical match condition but different processing content to be applied, and a condition for changing an application priority among said 2 or more flow entries; and

the switch that holds said 2 or more flow entries and switches application priority in accordance with a condition specified by said control apparatus, to process received packet(s),

wherein the condition specified by said control apparatus includes a threshold regarding a value whose changing amount is not predicted in advance and which is obtained from an object existing in the switch.

2. The communication system according to claim 1 , wherein said control apparatus prescribes, as said condition, content to change said application priority each time a counter value set in each flow entry exceeds a prescribed threshold, for said switch.

3. The communication system according to claim 2 , wherein said control apparatus prescribes, as said condition, content to change said application priority each prescribed time period, for said switch.

4. The communication system according to claim 2 , wherein said control apparatus determines a switch to transmit said 2 or more flow entries and said condition, based on a counter value for each flow entry collected from said switch.

5. The communication system according to claim 2 , wherein said control apparatus:

collects values of statistical information of packets dropped, without being transmitted with regard to respective ports, from said switch;

creates, with respect to a flow entry for which output from a port with many of said packets dropped is prescribed, a flow entry to prescribe output from another port having the identical match condition; and

transmits said created flow entry and a condition to change application priority among said 2 or more flow entries.

6. The communication system according to claim 1 , wherein said control apparatus prescribes, as said condition, content to change said application priority each prescribed time period, for said switch.

7. The communication system according to claim 6 , wherein said control apparatus determines a switch to transmit said 2 or more flow entries and said condition, based on a counter value for each flow entry collected from said switch.

8. The communication system according to claim 6 , wherein said control apparatus:

collects values of statistical information of packets dropped, without being transmitted with regard to respective ports, from said switch;

creates, with respect to a flow entry for which output from a port with many of said packets dropped is prescribed, a flow entry to prescribe output from another port having the identical match condition; and

transmits said created flow entry and a condition to change application priority among said 2 or more flow entries.

9. The communication system according to claim 1 , wherein said control apparatus determines a switch to transmit said two or more flow entries and said condition, based on a counter value for each flow entry collected from said switch.

10. The communication system according to claim 9 , wherein said control apparatus:

collects values of statistical information of packets dropped, without being transmitted with regard to respective ports, from said switch;

creates, with respect to a flow entry for which output from a port with many of said packets dropped is prescribed, a flow entry to prescribe output from another port having the identical match condition; and

transmits said created flow entry and a condition to change application priority among said 2 or more flow entries.

11. The communication system according to claim 1 , wherein said control apparatus:

collects values of statistical information of packets dropped, without being transmitted with regard to respective ports, from said switch;

creates, with respect to a flow entry for which output from a port with many of said packets dropped is prescribed, a flow entry to prescribe output from another port having the identical match condition; and

transmits said created flow entry and a condition to change application priority among said 2 or more flow entries.

12. The communication system according to claim/wherein said switch transmits statistical information of packets dropped without being transmitted for each port of said switch, in port units or collectively for each switch, to said control apparatus.

13. The communication system according to claim 1 , wherein the switch includes a queue information transmitter transmitting queue information indicating a counted number of packets dropped.

14. The communication system according to claim 1 , wherein said control apparatus collects values of statistical information of packets dropped, without being transmitted with regard to respective ports, from said switch.

15. The communication system according to claim 14 , wherein said control apparatus creates, with respect to a flow entry for which output from a port with a number of said packets dropped is prescribed, a flow entry to prescribe output from another port having the identical match condition.

16. The communication system according to claim 1 , wherein said control apparatus creates, with respect to a flow entry for which output from a port with a number of packets dropped is prescribed, a flow entry to prescribe output from another port having the identical match condition.

17. A switch, connected to a control apparatus that transmits to the switch 2 or more flow entries having an identical match condition but different processing content to be applied, and a condition for changing application priority among said 2 or more flow entries,

the switch holding said 2 or more flow entries, and switching an application priority in accordance with a condition prescribed by said control apparatus, to process received packet(s),

wherein the condition prescribed by said control apparatus includes a threshold regarding a value whose changing amount is not predicted in advance and which is obtained from an object existing in the switch.

18. A control apparatus that transmits to a switch which holds 2 or more flow entries having an identical match condition but different processing content to be applied, and switches an application priority among said 2 or more flow entries in accordance with a specified condition, to process received packet(s),

the control apparatus transmitting to a switch said 2 or more flow entries and said condition for changing said application priority among said 2 or more flow entries,

wherein the specified condition by said control apparatus includes a threshold regarding a value whose changing amount is not predicted in advance and which is obtained from an object existing in the switch.

19. A packet processing method, comprising:

receiving, from a control apparatus, 2 or more flow entries having an identical match condition but different processing content to be applied, and a condition for changing an application priority among said 2 or more flow entries; and

holding, by a switch, said 2 or more flow entries and switching application priority in accordance with a condition specified by said control apparatus, to process received packet(s),

wherein the condition specified by said control apparatus includes a threshold regarding a value whose changing amount is not predicted in advance and which is obtained from an object existing in the switch.

20. A non-transitory computer-readable recording medium storing thereon a program to execute on a computer that controls a switch that holds 2 or more flow entries having an identical match condition but different processing content to be applied, and switches an application priority among said 2 or more flow entries in accordance with a specified condition, to process received packet(s), said program executing

a process of creating said 2 or more flow entries and a condition for changing the application priority among said 2 or more flow entries; and

a process of transmitting said 2 or more flow entries and said condition to said switch,

wherein the specified condition includes a threshold regarding a value whose changing amount is not predicted in advance and which is obtained from an object existing in the switch.