Router assisted schemes for performance improvement in the Internet

Congestion handling in the TCP protocol is through implicit feedback about the network conditions to the traffic source. If the feedback can be obtained sooner at the source, the congestion handling can be more effective. The goal of this work is to expedite the feedback process and enhance the performance of the Internet under congestion. We motivate the need for the proposed schemes with the help of a simplified analytical model which evaluates the time to detect a packet loss through duplicate acknowledgements. We show that this time can be significant when the number of flows going through a router is large. We then present two schemes, Triple Packet Buffering on Congestion, and Triple Truncated Packets, that enables congestion information to be fed back to the source faster. This results in a faster response to congestion conditions, and a faster retransmission of discarded packets. With the help of simulation results, we show that the proposed schemes perform better than the standard implementation in a variety of network scenarios and achieve higher throughput and lower mean delay. This scheme also does not require any changes in the standard TCP protocols, but a simple (optional) modification at the routers.