确保服务中一种基于动态阈值的数据包标记算法

确保转发过程中带宽享用的公平性问题一直是区分服务网络研究的热点，影响这种公平性的因素包括回路响应时间RTT、数据包大小、目标速率及聚流中包含的单流数量等．确保服务的实现依赖于在边界路由器执行的数据包标记策略和在核心路由器执行的队列管理策略，基于动态阈值的数据包标记策略DTBM的目的就是处理异质的TCP流之间带宽享用的公平性问题。DTBM通过测量局部吞吐量来调整标记算法中的阈值，以改变不同颜色的标记概率从而达到公平带宽享用的目的。DTBM的主要优点在于其实现简单、对参数不是很敏感并且对端结点主机是“透明”的，仿真实验表明，和其他几种标记算法相比，DTBM能有效地消除上述因素的影响，具有更好的公平性。

Dynamic Threshold Based Packet Marking for Assured Services

Issues related to fair sharing of bandwidth in assured forwarding based differentiated services networks have been discussed in many research papers. Some of the factors that can bias fair sharing of bandwidth are round trip time (RTT), packet size, the number of flows in aggregate and target rate etc. The assured services architecture relies on packet marking mechanism at the edge router, and on queue management mechanism at the core router. The purpose of DTBM is to achieve proportional fair sharing of bandwidth among heterogeneous TCP flows. By measuring local throughput to adjust the threshold, DTBM can change the marking probability to achieve fairness. The major benefits of DTBM are its simplicity, least sensitivity to parameters, and transparency to the end hosts. The simulation results indicate that compared to TSW2CM, CATC, TokenBucket, and srTCM for different network scenarios, DTBM performs better in providing fairness among heterogeneous TCP flows.