基于时空二维资源分配的跨域虚拟网嵌入理论与方法研究

虚拟网嵌入是实现网络虚拟化的重要过程，是当前的热点研究。但现有研究成果多集中在面向单个物理网络域而缺乏考虑跨多个物理网络域的嵌入问题；且往往仅考虑虚拟网构建的空间维度特性需求，忽视了对时间特性需求的考虑。为此，本课题拟从网络资源互斥访问机制及带宽与时间两个资源维度入手，深入分析跨域虚拟网嵌入问题的特点，从以下四个方面寻求对现有虚拟网嵌入理论的突破和创新：1）研究基于令牌环的分布式协同策略，以解决多个虚拟网跨域并发嵌入产生的资源访问冲突问题；2）提出"二维负载均衡"的概念并采用离散加权法研究其度量问题；3）提出"资源碎片"的概念并采用元碎片方法和粗糙集理论研究其度量问题；进而基于路径集拓展多商品流问题模型并采用多目标规划方法，对跨域虚拟网嵌入问题进行建模、求解；4）采取局部重嵌入策略，研究受损虚拟网的快速愈合方法。最终形成一套网络资源优化利用的跨域虚拟网嵌入理论与方法。

As one of the key process for realizing network virtualization, VN (virtual network) embedding has become an increasingly important research area. However, previous work only focused on the embedding problem in a single infrastructure network domain scenario, while VNs may be provisioned across a set of heterogeneous administrated domains in reality. In addition, the existing works ignore the temporal properties of VNs, which only concerns the spatial properties of VN. Based on the deep analysis on the characteristic of cross-domain VN embedding problem, this project will study the mutual exclusion mechanism for accessing network resources and spatial-temporal characteristic of resources to acquire breakthroughs and innovations on VN embedding theory as follows: 1) a token ring-based distributed collaborative strategy is proposed, in order to address the access conflict of network resource caused by multiple VN embedding concurrently; 2) an indicator of two-dimensional load balance is introduced, and a discrete weighted method is proposed to measure it; 3) a concept of resource fragmentation is suggested, and a meta fragmentation method and rough set theory are used to measure its size; then, the cross-domain VN embedding problem is formulated based on extended multi-commodity flow model based on path set and multi-objective mathematical programming; 4) a strategy of rapidly healing damaged VN caused by link fails is proposed with the use of local re-embedding method. In conclusion, a set of cross-domain VN embedding theories and methods is formed to optimize the utilization of network resources.