Switch cost and packet delay tradeoff in data center networks with switch reconfiguration overhead
Switch cost and packet delay tradeoff in data center networks with switch reconfiguration overhead
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DOI：
10.1016/j.comnet.2015.05.010
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发表时间：
2015-07
期刊：
影响因子：
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通讯作者：
Shu Fu;Bin Wu;Xiaohong Jiang;A. Pattavina;H. Wen;Hongfang Yu
中科院分区：
文献类型：
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作者：
Shu Fu;Bin Wu;Xiaohong Jiang;A. Pattavina;H. Wen;Hongfang Yu
成本最小化是数据中心网络（DCN）中的主要关注点。现有的DCN一般采用带有交叉开关中间交换机的Clos网络来实现服务器之间的无阻塞数据交换，中间交换机的数量与汇聚交换机的端口数量成固定比例。此外，交换机的重配置开销通常被忽略，这可能与工程实践相矛盾。在本文中，我们考虑批调度的数据包交换在DCN的重配置开销在每个中间开关，这不可避免地导致数据包延迟。利用现有的最先进的流量矩阵分解算法，我们可以生成一组排列，其中每个排列代表中间交换机的配置。通过重新配置每个中间交换机，以满足多个配置与其他并行，我们揭示了一个折衷存在于数据包延迟和交换机成本（由中间交换机的数量表示）之间，而性能保证交换有界的数据包延迟可以实现没有任何数据包丢失。基于权衡，我们可以最大限度地减少中间交换机的数量（在给定的数据包延迟范围内）和整体成本度量（通过将延迟转换为可比的成本因素），以及制定标准选择一个合适的矩阵分解算法。这提供了一种灵活的方式来通过稍微扩大分组延迟界限来减少中间交换机的数量。
Cost minimization is a major concern in data center networks (DCNs). Existing DCNs generally adopt Clos network with crossbar middle switches to achieve non-blocking data switching among the servers, and the number of middle switches is proportional to the number of ports of the aggregation switches in a fixed manner. Besides, reconfiguration overhead of the switches is generally ignored, which may contradict the engineering practice. In this paper, we consider batch scheduling based packet switching in DCNs with reconfiguration overhead at each middle switch, which inevitably leads to packet delay. With existing state-of-the-art traffic matrix decomposition algorithms, we can generate a set of permutations, each of which stands for the configuration of a middle switch. By reconfiguring each middle switch to fulfill multiple configurations in parallel with others, we reveal that a tradeoff exists between packet delay and switch cost (denoted by the number of middle switches), while performance guaranteed switching with bounded packet delay can be achieved without any packet loss. Based on the tradeoff, we can minimize the number of middle switches (under a given packet delay bound) and an overall cost metric (by translating delay into a comparable cost factor), as well as formulating criteria for choosing a proper matrix decomposition algorithm. This provides a flexible way to reduce the number of middle switches by slightly enlarging the packet delay bound.