Patent ID: 7363405

Claim:
A communication control apparatus which functions as an initiator and communicates with an external device functioning as a target in the IEEE 1394.3, comprising: a storage unit, configured to store information expressing a plurality of functions that the communication control apparatus is capable of providing and storing a plurality of unit directories each of which corresponds to respective functions; a communication unit, configured to communicate data located in an address designated by the external device with the external device; a receiving unit, configured to receive from the external device data including a directory ID which specifies a unit directory to which the target tries to connect; and a determining unit, configured to determine whether a unit directory corresponding to the directory ID exists in the initiator, wherein said communication unit communicates with the external device in accordance with a method standardized in IEEE 1394.3 in a case where said determining unit determines that the unit directory corresponding to the directory ID exist in the initiator, and wherein said communication unit does not communicate with the external device in accordance with a method standardized in IEEE 1394.3 in a case where said determining unit determines that the unit directory corresponding to the directory ID does not exist in the initiator.