IP网络坐标抖动感知与慢启动抑制

IP-Based Network Coordinate Oscillation Awareness and Slow-Start Mitigation

为了抑制Vivaldi网络坐标系统抖动现象并提高距离预测准确性,将Vivaldi归结为一类非线性方程组的迭代求解算法,并基于方程组的矛盾性提出了迭代因子的自适应估计问题。据此,定义单位化误差作为新的度量参数,通过对该参数的周期性测量实现坐标抖动的感知。进而对迭代过程进行逻辑分层,提出了一种基于慢启动策略的抖动抑制算法。实验证明,算法不依赖于迭代因子的人工选取,能够在不损失定位精度和收敛速度的前提下,将节点坐标抖动程度降低83.5%以上,并能与Vivaldi协议混合部署,实现坐标系统的平滑演进。

To mitigate oscillation phenomenon in Vivaldi Network Coordinate System （NCS） and improve the accuracy of Intemet distance prediction, Vivaldi is categorized as a kind of iterative method to solve non-linear equations and thus the adaptive estimation of iterative factor in Vivaldi is raised based on equations＇ contradictory. By defining a new metric unitization error and measuring it periodically, the awareness of network coordinate oscillation degree can be achieved in real time. Then we separate the iterative process of Vivaldi into 2 logical layers and propose a simple slow-start adaptive algorithm to estimate iterative factor automatically in order to mitigate network coordinate oscillation. The experiments and simulations show this algorithm can reduce the coordinate oscillation by no less than 83.5% without losing any velocity and accuracy, no matter what the initial value of iterative factor is. Furthermore, this algorithm can also be deployed in a hybrid environment together with raw Vivaldi to make the update of NCS smoothly.