基于可用带宽测量的分层组播拥塞控制机制

Multicast Congestion Control Mechanism Based on Available Bandwidth Measurement

针对现有的组播拥塞控制机制对接收端可用带宽估计精度较低的问题,提出了一种基于可用带宽测量的分层组播拥塞控制机制ABM-LMCC。在分析了现有可用带宽估计方法不足的基础上,提出一种适用于组播的可用带宽测量算法,并设计了分层组播拥塞控制机制的具体操作规程。通过调节组播数据包的发送间隔,使其呈现降速率的指数分布,从而实现各接收端对可用带宽的准确测量,并根据其测量值迅速调节期望速率,从而达到组播拥塞控制的目的。仿真表明,ABM-LMCC能够有效避免拥塞,提高链路利用率,显著降低丢包率,具有良好的响应性、稳定性。

Most existing multicast congestion control mechanisms have the problem of low accuracy in available bandwidth estimation,so a layered multicast congestion control mechanism based on available bandwidth measurement （ABM-LMCC） is proposed.An available bandwidth measurement method for multicast is introduced after analysis on the existing available bandwidth estimation methods.The specific operating procedures of the layered multicast congestion control mechanism are designed.By adjusting the transmission interval of the multicast packet,so that it presents to the exponential distribution of the drop rate and each receiver measure the available bandwidth accurately.And the expected rate is quickly adjusted based on the measurement values,so as to achieve the multicast congestion control.Simulations show that the ABM-LMCC is able to avoid congestion effectively,improve link utilization and significantly reduce packet loss rate,and has good response as well as stability.