Apparatus and method for reestablishing a security association used for communication between communication devices

A communication apparatus comprising:

• a processor coupled to a memory, the processor being configured:
• to monitor a communication situation of a communication performed using each of a plurality of security associations established between the communication apparatus and a counterpart apparatus, and store information indicating the communication situation in the memory,
• to, when a first security association in the plurality of security associations is disconnected, determine whether the counterpart apparatus uses the disconnected first security association, based on the information, and
• to, when the counterpart apparatus uses the first security association, reestablishing, reestablish a second security association which supersedes the first security association;
• and
• the memory configured to store the information indicating the communication situation.

A system comprising:

• a communication apparatus;
• and
• a counterpart apparatus configured to communicate with the communication apparatus by using a security association, wherein
• the communication apparatus is configured:
• to monitor a communication situation of a communication performed using each of a plurality of security associations established between the communication apparatus and a counterpart apparatus, and store information indicating the communication situation,
• to, when a first security association in the plurality of security associations is disconnected, determine whether the counterpart apparatus uses the disconnected first security association, based on the information, and
• to, when the counterpart apparatus uses the first security association, reestablishing, reestablish a second security association which supersedes the first security association.