Gateway apparatus and method of controlling gateway apparatus

The present invention enables a packet, in which packet information is set, to be transmitted between a plurality of apparatuses using protocols in different layers. This gateway apparatus is installed in a core network of a mobile wireless communication system and is connected as a gateway to another network other than the core network, the gateway apparatus having: an extracting means for extracting first information set in a first packet received from a relay apparatus for relaying a packet between the gateway apparatus and a wireless terminal or from a node installed in the other network; a setting means for setting second information on the basis of the first information with respect to a second packet of a protocol in a layer different from that of the protocol of the first packet; and a transmission means for transmitting the second packet in which the second information is set to the node or the relay apparatus.