An apparatus and a method for performing data transfer that can ensure QoS of data transmitted and received are provided. IEEE802.1p priority tags as priority identifiers are set under control of a tag managing terminal. A priority tag is set for a data flow to be subjected to priority processing, for example, to be guaranteed QoS so as to prevent duplicate use of a queue in a communication control apparatus such as a switch or the like connected to a network. The tag managing terminal for example converts a queue use state in intra-subnetwork communication into a table, and retains the table. In response to a queue request from each terminal, the tag managing terminal refers to the table and then assigns a tag. The communication control apparatus such as the switch or the like that executes data transfer control prevents duplicate queue generation for data flows to be subjected to priority processing only by processing using the priority table associating tags with queues.