Partial Reliable TCP

Abstract

Some new information services over IPbased networks such as video streaming and VoIP (Voice over IP) can tolerate some packets lost in transmission without too much damage to their quality. The content carried in the packets of these services is not equally important in their replay processes. Unfortunately, the two most popular transport protocols, UDP and TCP, treat all packets equally without any discrimination. This paper proposes a new TCP protocol, named Partial- Reliable TCP (PR-TCP), which applies selective retransmission strategy to provide delivery guarantee to the selected packets designated by the application programs. In this way, we can save bandwidth consumption and reduce average delivery time without significant quality degradation. Two versions are proposed: Basic PR-TCP and Single-Side PR-TCP. Basic PR-TCP requires both ends of a connection to adopt PRTCP while Single-Side PR-TCP only requires the sender end to adopt it. We use NS-2 network simulator to evaluate PR-TCP against TCP Reno, TFRC and UDP. Two video stream samples are used for video sources. The simulation shows that PR-TCP can have better performance under various conditions.