PACKET TRANSFER SYSTEM, PACKET TRANSFER METHOD, COMMUNICATION APPARATUS AND PACKET TRANSFER PROGRAM

PROBLEM TO BE SOLVED: To transmit an encryption packet while reducing a header size of the packet rather than a conventional generic routing encapsulation (GRE)-over-IPsec communication system, and to perform packet transmission while reducing tunnel setup steps. SOLUTION: In a packet transfer system, a transfer packet is encapsulated according to a predetermined key exchange protocol and transferred between a first communication apparatus and a second communication apparatus which is opposed to the first communication apparatus. The first communication apparatus has a mode notifying means for notifying the second communication apparatus of an encapsulation system that the first communication apparatus requests, in the case of negotiation with the second communication apparatus according to the key exchange protocol. The second communication apparatus has a mode recognizing means for recognizing the encapsulation system that the first communication apparatus requests. The first communication apparatus and the second communication apparatus have tunnel setting means for setting a tunnel according to the encapsulation system using the key exchange protocol. COPYRIGHT: (C)2011,JPO&INPIT