Patent ID: 7082467

Claim:
A device for use in a system comprising said device, a first apparatus, and a second apparatus, said device comprising: a selective spoofing unit that (a) obtains, from a transport level connection between the first apparatus and the second apparatus, a transport level packet sent by the first apparatus to the second apparatus, (b) determines, in accordance with a value in a field of the transport level packet, what application is using the transport level connection, (c) decides whether or not to perform transport level spoofing on the transport level connection, in accordance with the determination of what application is using the transport level connection, (d) selectively performs transport level spoofing on the transport level connection in accordance with the decision of whether or not to perform transport level spoofing, wherein the transport level spoofing comprises (i) locally acknowledging, to the first apparatus, receipt of the transport level packet and (ii) taking on, from the first apparatus, the responsibility of retransmitting the transport level packet if necessary, (e) decides, in a case that said selective spoofing unit has decided to perform transport level spoofing on the transport level connection, whether or not to modify the transport level packet, in accordance with the determination of what application is using the transport level connection, (f) selectively modifies the transport level racket in accordance with the decision of whether or not to modify the transport level packet, and (g) sends the transport level packet, having been modified if such is decided, to the second apparatus, wherein at least one of the following conditions is satisfied: (1) the selective modification comprises varying the following field of the transport level packet: a TCP Option, TCP Maximum Segment Size; (2) the selective modification comprises varying the following field of the transport level packet: a three-way handshake parameter field, and (3) the selective modification comprises varying the following field of the transport level packet: a connection priority field.