A communication apparatus includes: a capability-information generating section which generates a first capability information including a first receivable-period information in relation to a first receivable period; a first transmission section which transmits the first capability information to the communication-destination device via the IP network; a first receiving section which receives a first data transmitted from the communication-destination device via the IP network during the first receivable period; a storage section in which a second data to be transmitted to the communication-destination device is stored; a second receiving section which receives a second capability information including a second receivable-period information in relation to a second receivable period; and a second transmission section which transmits a second data stored in the storage section to the communication-destination device during the second receivable period based on the second capability information.