An Explicit Congestion Control Protocol Based on Bandwidth Estimation

Jianxin Wang, Jie Chen, Shigeng Zhang, Weiping Wang

Abstract: Explicit feedback based congestion control schemes can capture network congestion status more accurately than pure end-to-end schemes. However, some of such schemes require modifying IP header in order to achieve near optimal performance, which incurs complicated computation in routers as well as makes them difficult to deploy in real networks. In contrast, the VCP protocol achieves good performance by using the two existing ECN bits in the IP header for feedback, but its convergence speed is relatively low due to insufficient congestion feedback. In this paper, we propose VCP-BE, a protocol based on VCP and uses end-to-end bandwidth estimation to obtain high resolution congestion estimation. With the estimated available bandwidth and ECN feedback, VCP-BE adjusts the congestion window more precisely than VCP thus converges much faster. Simulation results show that VCP-BE outperforms VCP and MLCP, achieving high efficiency and reasonable fairness.