A TCP-Friendly Congestion Control Scheme Using Hybrid Approach for Reducing Transmission Delay of Real-Time Video Stream

Abstract

Recently, due to the high development of the Internet, the need for multimedia streams such as digital audio and video is increasing more and more. In the case of transmitting multimedia streams using the User Datagram Protocol (UDP), it may cause starvation of TCP traffic on the same transmission path, thus resulting in congestion collapse and an enormous delay because UDP does not perform TCP-like congestion control. Because of this problem, diverse research is being conducted on new transmission schemes and protocols intended to efficiently reduce the transmission delay of real-time multimedia streams and perform congestion control. The TCP-friendly congestion control schemes can be classified into the window-based congestion control, which uses the general congestion window management function, and the rate-based congestion control, which dynamically adjusts transmission rate by using TCP modeling equations. In this paper, we suggest the square-root congestion avoidance algorithm with the hybrid TCP-friendly congestion control scheme in which the window-based and rate-based congestion controls are dealt with in a combined way. We apply the proposed algorithm to the existing TEAR. We simulate the performance of the proposed TEAR by using NS, and the result shows that it gives better improvement in respect to stability needed for providing congestion control than the existing TEAR.