arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0805.2185cs.NIcs.ITmath.IT
收藏

分组交换网络路径分集:性能分析和速率分配

Path Diversity over Packet Switched Networks: Performance Analysis and Rate Allocation

Shervan Fashandi, Shahab Oveis Gharan, Amir K. Khandani

摘要:

路径多样性通过使用网络的拓扑路径冗余在端点之间建立多个并行连接来工作。在本文中,\textit{Forward Error Correction}(FEC)应用于多个独立的路径,以提高端到端的可靠性。网络路径被建模为擦除Gilbert-Elliot信道。已知在任何擦除信道上,\textit{Maximum Distance Separable}(MDS)码在所有相同大小的块码中实现不可恢复丢失的最小概率。基于所采用的模型的错误行为,我们证明了MDS码的不可恢复的损失的概率指数衰减的渐近大量的路径。然后,最优速率分配问题的渐近情况下,路径数是大的解决。此外,它表明,在这样的渐近最优速率分配,每一条路径被分配一个积极的速率\textit{iff}其质量是在一定的阈值以上。路径的质量被定义为它处于不良状态的时间百分比。最后,利用动态规划,提出了一个多项式时间的启发式次优算法,用于有限条路径上的速率分配。当路径数较多时,该算法收敛于渐近最优速率分配。仿真结果表明,该算法近似的最优速率分配(发现穷举搜索)非常接近实际路径数,并提供了显着的性能改善相比,替代方案的速率分配。

英文摘要:

Path diversity works by setting up multiple parallel connections between the end points using the topological path redundancy of the network. In this paper, \textit{Forward Error Correction} (FEC) is applied across multiple independent paths to enhance the end-to-end reliability. Network paths are modeled as erasure Gilbert-Elliot channels. It is known that over any erasure channel, \textit{Maximum Distance Separable} (MDS) codes achieve the minimum probability of irrecoverable loss among all block codes of the same size. Based on the adopted model for the error behavior, we prove that the probability of irrecoverable loss for MDS codes decays exponentially for an asymptotically large number of paths. Then, optimal rate allocation problem is solved for the asymptotic case where the number of paths is large. Moreover, it is shown that in such asymptotically optimal rate allocation, each path is assigned a positive rate \textit{iff} its quality is above a certain threshold. The quality of a path is defined as the percentage of the time it spends in the bad state. Finally, using dynamic programming, a heuristic suboptimal algorithm with polynomial runtime is proposed for rate allocation over a finite number of paths. This algorithm converges to the asymptotically optimal rate allocation when the number of paths is large. The simulation results show that the proposed algorithm approximates the optimal rate allocation (found by exhaustive search) very closely for practical number of paths, and provides significant performance improvement compared to the alternative schemes of rate allocation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑