Abstract: For the virtual network embedding in Software Defined Network (SDN), the existing researchers mainly consider the acceptance rate, but ignore the problem of the underlying resource failure in SDN. Aiming at the problem of Survivable Virtual Network Embedding (SVNE) in SDN, a virtual network embedding guarantee mechanism was proposed combining priori protection and posteriori recovery. Firstly, the regional resources of SDN physical network were perceived before a virtual request was accepted. Secondly, the backup physical resources for the virtual network elements with relatively reduced remaining resources in the mapping domain were reserved by the priori protection mechanism, and the extended virtual network was embedded into the physical network by the D-ViNE (Deterministic Virtual Network Embedding) algorithm. Finally, when a network element without reserved backup resources was out of order, the fault was recovered by the posterior recovery algorithm, which means the node and the link were recovered by remapping and rerouting respectively. Experimental results show that compared with the SDN-Survivability Virtual Network Embedding algorithm (SDN-SVNE), the proposed mechanism has the virtual request acceptance rate increased by 21.9%. And this protection mechanism has advantages in terms such as virtual level fault recovery rate and physical level fault recovery rate.

Key words: Software Defined Network (SDN), network virtualization, Virtual Network Embedding (VNE), reliability, remapping

摘要： 在软件定义网络（SDN）虚拟网络映射中，现有研究者主要考虑请求接受率方面，而忽视了SDN中底层资源失效的问题。为此，针对SDN中可靠性虚拟网络映射（SVNE）问题，提出了一种联合先验式保护和后验式恢复的虚拟网络映射保障机制。首先，在虚拟请求接受之前，对SDN物理网络区域性资源进行感知；然后，采用先验式保护机制为映射域内相对剩余资源变小的虚拟网络元素预留备份物理资源，并将此扩展虚拟网络通过D-ViNE算法映射至物理网络中；最后，在未备份虚拟网络元素发生故障时，采用后验式恢复算法完成故障的恢复，对节点和链路分别采用重映射和重路由的方法完成恢复。实验结果表明，与基于SDN的生存性虚拟网络映射算法（SDN-SVNE）相比，在虚拟请求接受率方面提高了21.9%。另外，该保护机制在虚拟级别故障恢复率、物理级别故障恢复率等方面也具有优势。

关键词: 软件定义网络, 网络虚拟化, 虚拟网络映射, 可靠性, 重映射