Abstract: A resegmentation entity implements a TCP resegmentation technique wherein a receiving host receives packets that appear as if it they have been transmitted specifically for the receiving host's MTU. The receiving host does not require the buffering and CPU utilization necessary for IP reassembly. Thus, the receiving host has a lower latency when receiving IP datagrams that contain resegmented TCP segments than it would if it needed to re-assemble an IP datagram from fragments before it could process the TCP segment. Further, the sending host transmits TCP segments at its largest MTU, without regard to the receiving station's MTU, knowing that the intermediate routing entity insures that TCP resegmentation occurs. In the event that an IP datagram containing a resegmented TCP segment is lost, the sending host only has to retransmit the actual TCP data that was lost, and not the complete TCP segment.

Abstract: A mechanism, referred to as MSS spoofing, intercepts and modifies the MSS value specified in a TCP SYN packet containing a TCP MSS option. As a result, the local TCP protocol stack is “spoofed” (i.e. made to believe) such that it appears to the local stack that the remote station has an MSS value that is different from its actual MSS value. MSS spoofing allows the local TCP protocol stack to use an MSS value that is derived solely from its own MTU. The interface changes the received MSS value to a value that is at least as large as the local MTU before passing the packet up the protocol stack. This forces the TCP protocol stack to use a larger MSS value than it would otherwise use. In this way, the TCP protocol stack always uses a TCP segment size that is based on the MTU of the local interface.