Proxy transport service for TCP-based active network applications

TCP performance degrades with increasing round trip time (rtt ). TCP uses the arrival rate of acknowledgments to determine its sending rate. Therefore large rtt, results in longer slow start periods and slower rate of increase of the congestion window. PTS (proxy transport service) is an active networks based service, deployed inside the network to improve the end-to-end performance of TCP connections with larger rtt's. PTS also helps to decrease the response time of TCP to congestion and can be used by other active services. A PTS session consists of two separate TCP connections, one between the sending host and a designated intermediate node (called the PTS node), and another between the PTS node and the receiving host. PTS node acknowledges all the TCP segments sent by the sending host immediately. PTS node inturn forwards this segment to the receiving host and stores a copy of it until an acknowledgment is received from the receiving host. Using simulation we have compared the performance of PTS and standard TCP. Also we have studied the effect of PTS node location, buffer size and service time on the performance of PTS. We have shown that a single proxy location cannot give the same performance to all the users. We are proposing PTS as a distributed service which provides the user the ability to choose a proxy based on its location.