Communication system including a switching section for switching a network route, controlling method and storage medium

A control method in a communication system which includes a client unit, a first node configured to perform processing in response to a request from said client unit, a second node configured to perform the processing in place of said first node when a fault has occurred in said first node, and communication units configured to configure network routes among said client unit, said first node and said second node, said control method comprising:

• determining whether a signal which is transmitted from said first node to said second node through a first network route of said network routes has been disconnected, onto the first network route;
• and
• switching a second network route of said network routes used when said client unit and said first node perform data communication to a third network route of said network routes used when said client unit and said second node perform data communication based on the determination result,
• wherein a communication unit of the communication units comprises a communication control section which includes a determining section for performing the determining of whether the signal has been disconnected, and a switching section for performing the switching of the second network route,
• wherein the communication unit further comprises a plurality of communication ports, and a flow table which is accessible by the communication control section and includes information for controlling a flow of data from the communication unit to a data transfer destination,
• wherein the information in the flow table includes:
• flow information which specifies identification information of the flow of data;
• output port information which specifies a communication port from which the data should be outputted;
• and
• operation information at disconnection which shows an operation to be performed when the flow of data has been disconnected,
• wherein the signal transmitted from the first node to the second node comprises a heartbeat signal which is transmitted from the first node to the second node via the communication unit,
• wherein if the heartbeat signal is not received by the communication unit for a predetermined period, then the communication unit determines that the flow has been disconnected, and refers to the flow table and performs an operation based on the operation information at disconnection corresponding to the flow, and
• wherein the communication units comprise an other communication unit which is not on a route for the heartbeat signal being transmitted from the first node to the second node, and a flow from the other communication unit is switched by the communication unit to the second node.

A computer-readable non-transitory storage medium which stores a computer-executable program code for attaining a control method in a communication system which includes a client unit, a first node configured to perform processing in response to a request from said client unit, a second node configured to perform the processing in place of said first node when a fault has occurred in said first node, communication units which configure network routes among said client unit, said first node and said second node, and a control unit provided onto a first network route of said network routes, said control method comprising:

• determining that a signal which is transmitted from said first node to said second node through said first network has been disconnected;
• outputting control signals from said control unit to said communication units;
• and
• performing a switching operation between a second network route of said network routes used when said client unit and said first node perform data communication and a third network route of said network routes used when said client unit and said second node perform data communication, by said communication units in response to said control signals,
• wherein a communication unit of the communication units comprises a communication control section which includes a determining section for performing the determining of whether the signal has been disconnected, and a switching section for performing the switching between the second and third network routes,
• wherein the communication unit further comprises a plurality of communication ports, and a flow table which is accessible by the communication control section and includes information for controlling a flow of data from the communication unit to a data transfer destination,
• wherein the information in the flow table includes:
• flow information which specifies identification information of the flow of data;
• output port information which specifies a communication port from which the data should be outputted;
• and
• operation information at disconnection which shows an operation to be performed when the flow of data has been disconnected,
• wherein the signal transmitted from the first node to the second node comprises a heartbeat signal which is transmitted from the first node to the second node via the communication unit,
• wherein if the heartbeat signal is not received by the communication unit for a predetermined period, then the communication unit determines that the flow has been disconnected, and refers to the flow table and performs an operation based on the operation information at disconnection corresponding to the flow, and
• wherein the communication units comprise an other communication unit which is not on a route for the heartbeat signal being transmitted from the first node to the second node, and a flow from the other communication unit is switched by the communication unit to the second node.