Patent ID: 7562130

Claim:
A gateway for use in a system wherein a first apparatus, said gateway, and a second apparatus are in a TCP/IP network, wherein the first apparatus, said gateway, and the second apparatus have different IP addresses, said gateway comprising: a memory; a packet receiving unit that is configured to receive a packet addressed at the IP level from the first apparatus to the second apparatus; and a service plan determining unit that is configured to determine a level of service subscribed to by a user of the first apparatus; a throttling unit that is configured to throttle the user of the first apparatus by (a) modifying the value of the TCP window size field of the packet so as to change the value from a value present in that field in the packet received by said packet receiving unit in accordance with (1) the level of service subscribed to by the user of the first apparatus and (2) bandwidth usage associated with the user of the first apparatus, and (b) sending the so modified packet to the second apparatus so that the second apparatus receives the so modified packet that has, in its TCP window size field, a value different from the value present in that field in the packet received by said packet receiving unit, wherein the packet received by said packet receiving unit has, as its source IP address, the IP address of the first apparatus, and has, as its destination IP address, the IP address of the second apparatus, wherein the modified packet sent to the second apparatus by said throttling unit has, as its source IP address, the IP address of the first apparatus, and has, as its destination IP address, the IP address of the second apparatus, and wherein a memory is included in said gateway.