异构网络下TCP拥塞控制疏导方法的研究与仿真

Under the Heterogeneous Network TCP Congestion Control Research and Simulation of Persuation Method

异构网络是由逻辑网构建而成,精确的TCP拥塞控制机制可以有效保障异构网络的稳定性,但采用传统算法进行异构网络的拥塞控制疏导时,难以辨别网络拥塞状态,存在异构网络拥塞控制疏导误差大的问题。为此,提出一种基于三重判决算法的异构网络下TCP拥塞控制疏导方法。首先定义异构网络传输时的丢包率(p LR)和RTT均值抖动积两个参数,利用模糊综合评价方法获取异构网络不同状态下的传输性能指标,计算出在异构网络不同状态下两个参数的隶属度函数,并利用三重判决算法对当前的异构网络状态进行判断,给定合理使用带宽且又不发生拥塞的当前缓存报文比特数取值范围,并设置慢启动门限对异构网络拥塞状态进行控制疏导。仿真结果表明,基于三重判决算法的异构网络下TCP拥塞控制疏导方法能够有效的保证异构网络的健壮性与稳定性。

Heterogeneous network is constructed by the logic network. Accurate TCP congestion control mechanism can effectively guarantee the stability of the heterogeneous network. But the traditional algorithm for congestion control dredging in heterogeneous network, it is difficult to distinguish network congestion state, leading to big error problem of congestion control dredging in heterogeneous network. Therefore, based on trebling decision algorithm, a TCP congestion control dredging method for heterogeneous network is proposed. Firstly, the two parameters of packet loss rate （PLR） and the RTI＂ mean jitter product in heterogeneous network transmission are defined. Using fuzzy comprehensive evaluation method, the transfer performance index of heterogeneous network under different conditions are gotten, and the membership functions of two parameters in the heterogeneous network under different conditions are calculated. On this basis, the use of trebling decision algorithm judges the current state of the heterogeneous network, to give the data range of current cache message bit number which can rationally use bandwidth and does not generate congestion, and set slow start threshold, making controlling and dredging for the congestion state in heterogeneous network. Simulation results show that the proposed method can effectively guarantee the robustness and stability of heterogeneous network.