A proxy device configured for use with a windowing Internet Protocol (IP) data network according to an embodiment of the invention includes a communication interface configured to intercept a first window of data packets transmitted from a source into the data network, transmit an acknowledgement from the proxy device to the source, and transmit the first window of data packets back into the network. The proxy device further includes a processing system configured to communicate with the communication interface, receive the first window of data packets, and generate the acknowledgement in response to the first window of data packets.