Abstract: A computer system according to the present invention includes a controller, and a switch which carries out a relay operation on a received packet which conforms to a flow entry which is set by the controller, the relay operation being regulated with the flow entry. The switch transmits a received packet which does not conform to the flow entry which is set by the switch to the controller. The controller queries authentication information which is included in the received packet and authenticates the received packet. From among the header information of the received packet which is determined to be valid, the controller sets the switch to the flow entry which regulated the relay operation for the packet which includes information which identifies the transmission source of the received packet. Network access policy control in a computer system of an open flow protocol environment is thus made easy.

Abstract: A computer system according to the present invention includes a controller, and a switch which carries out a relay operation on a received packet which conforms to a flow entry which is set by the controller, the relay operation being regulated with the flow entry. The switch transmits a received packet which does not conform to the flow entry which is set by the switch to the controller. The controller queries authentication information which is included in the received packet and authenticates the received packet. From among the header information of the received packet which is determined to be valid, the controller sets the switch to the flow entry which regulated the relay operation for the packet which includes information which identifies the transmission source of the received packet. Network access policy control in a computer system of an open flow protocol environment is thus made easy.

Abstract: A controller sets, for a first switch, a flow entry whose rule is header information of a delay measurement packet and whose action is forwarding to a second switch, and transmits the delay measurement packet to the first switch. The first switch forwards the delay measurement packet received from the controller to the second switch, in accordance with the flow entry set in the first switch. An analyzing module obtains the delay measurement packet from the second switch and calculates a delay time in a communication section between the first switch and the second switch by using a time stamped on the delay measurement packet.