Communication system, communication apparatus, control apparatus, communication apparatus control method and program

A communication system, comprising:

• a plurality of communication apparatuses that process a received packet(s) based on externally-set communication control information;
• and
• a plurality of control apparatuses that set the communication control information in the plurality of communication apparatuses,
• wherein, when a first control apparatus that sets the communication control information in a first communication apparatus is replaced by a second control apparatus, a control information notification unit in the first communication apparatus notifies the second control apparatus of the communication control information that was set in the first communication apparatus by the first control apparatus, and
• the second control apparatus thereafter takes over control of the first communication apparatus by using the notified communication control information received from the first communication apparatus,
• wherein the plurality of control apparatuses further comprise a communication control information validity determination unit that determines whether the notified communication control information is consistent with communication control information that has already been set in the plurality of communication a apparatuses, and
• the determination is made based on whether non-arrival of a packet is caused by reference to the notified communication control information that is set in a packet forwarding apparatus under the control.

A communication apparatus, connected to a plurality of control apparatuses setting communication control information in the communication apparatus, the communication apparatus comprising:

• a packet processing unit that processes a received packet(s) based on communication control information set by at least one of the plurality of control apparatuses;
• and
• a control information notification unit that notifies, when the at least one control apparatus, which sets the communication control information in the communication apparatus, is replaced by another control apparatus, the another control apparatus as replaced of the communication control information set in the communication apparatus,
• wherein the plurality of control apparatuses further comprise a communication control information validity determination unit that determines whether the notified communication control information is consistent with communication control information that has already been set in the plurality of communication apparatuses, and
• the determination is made based on whether a loop of a packet is caused by using the notified communication control information in setting of a packet forwarding apparatus under the control of the communication control information validity determination unit by reference to topology information constituted by packet forwarding apparatus(es) under the control.

A control apparatus, comprising:

• at least one data port so that the control apparatus can be configured to be connected to a plurality of communication apparatuses processing a received packet(s) based on externally-set communication control information;
• and
• a communication apparatus control unit, as implemented by a processor on the control apparatus, so that the control apparatus can be configured to take over control of a communication apparatus by using communication control information that had been previously set in the communication apparatus by another control apparatus and that is notified to the control apparatus by the communication apparatus,
• wherein the plurality of control apparatuses further comprise a communication control information validity determination unit that determines whether the notified communication control information is consistent with communication control information that has already been set in the plurality of communication apparatuses, and
• the determination is made based on whether a loop of a packet is caused by using the notified communication control information in setting of a packet forwarding apparatus under the control of the communication control information validity determination unit by reference to topology information constituted by packet forwarding apparatus(es) under the control.

A method for controlling a communication apparatus processing received packets based on externally-set communication control information, the method comprising:

• by a first control apparatus, setting the communication control information in the communication apparatus;
• by the communication apparatus, when the first control apparatus setting the communication control information in the communication apparatus is replaced by a second control apparatus, notifying the second control apparatus of the communication control information set in the communication apparatus by the first control apparatus;
• and
• by the second control apparatus, starting control of the communication apparatus by using the notified communication control information,
• wherein the first and second control apparatuses further comprise a communication control information validity determination unit that determines whether the notified communication control information is consistent with communication control information that has already been set in the first and second communication apparatuses, and
• the determination is made based on whether a loop of a packet is caused by using the notified communication control information in setting of a packet forwarding apparatus under the control of the communication control information validity determination unit by reference to topology information constituted by packet forwarding apparatus(es) under the control.

A non-transitory computer-readable recording medium storing a program that causes a computer on a communication apparatus that is connected to a plurality of control apparatuses, each control apparatus configured for potentially setting communication control information in the communication apparatus, the communication apparatus processing received packets based on communication control information set by at least one of the plurality of control apparatuses, to execute:

• detecting whether the at least one control apparatus which sets the communication control information in the communication apparatus is replaced;
• and
• notifying, when the at least one control apparatus which sets the communication control information in the communication apparatus is replaced by another control apparatus, the another control apparatus of the communication control information set in the communication apparatus by the at least one control apparatus,
• wherein the plurality of control apparatuses further comprise a communication control information validity determination unit that determines whether the notified communication control information is consistent with communication control information that has already been set in the plurality of communication apparatuses, and
• the determination is made based on whether a loop of a packet is caused by using the notified communication control information in setting of a packet forwarding apparatus under the control of the communication control information validity determination unit by reference to topology information constituted by packet forwarding apparatus(es) under the control.

A non-transitory computer-readable recording medium, storing a program, that causes a computer, which is mounted on a control apparatus connected to a plurality of communication apparatuses processing a received packet(s) based on externally-set communication control information, to execute:

• receiving communication control information from a communication apparatus controlled by another control apparatus;
• and
• starting control of the communication apparatus by using the communication control information,
• wherein the control apparatus further comprises a communication control information validity determination unit that determines whether the notified communication control information is consistent with communication control information that has already been set in the communication apparatus, and
• the determination is made based on whether a loop of a packet is caused by using the notified communication control information in setting of a packet forwarding apparatus under the control of the communication control information validity determination unit by reference to topology information constituted by packet forwarding apparatus(es) under the control.

A non-transitory computer-readable recording medium storing a program that causes a computer on a control apparatus connected to a communication apparatus processing received packets based on externally-set communication control information to execute:

• receiving communication control information from the communication apparatus;
• and
• updating a state of communication control information that is stored in the control apparatus and that is set for the communication apparatus based on the received communication control information from the communication apparatus,
• wherein the control apparatus further comprise a communication control information validity determination unit that determines whether the notified communication control information is consistent with communication control information that has already been set in the communication apparatus, and
• the determination is made based on whether a loop of a packet is caused by using the notified communication control information in setting of a packet forwarding apparatus under the control of the communication control information validity determination unit by reference to topology information constituted by packet forwarding apparatus(es) under the control.