The elastic optical network is one of the emerging technologies in the optical network paradigm, and it has been highlighted by many researchers in the past few years. So far, a comprehensive study has been conducted on routing and spectrum assignment in elastic optical networks. However, only a few works considered the problem of failure, protection, and recovery to enable seamless data transportation through the elastic optical networks. In this paper, we classify and review some different techniques to protect the traffic demands from failure and propose a p-cycle based protection approach for multicast traffic demands. A grooming technique is adopted and incorporated into the protection based techniques, to enhance the spectrum utilization efficiency by the traffic demands. We compare the proposed algorithm with some state-of-the-art protection based approaches. It is evident from the results that the proposed p-cycle based approach outperforms the other approaches concerning resources utilization ratio and execution time and grooming helps to reduce the spectrum resources required along with primary and backup resources. Finally, we discuss some of the important research areas, their scope, and challenges which are relevant to protection and recovery based studies in elastic optical network paradigm.

弹性光网络是光网络范式中的新兴技术之一，并且在过去几年中被许多研究人员所强调。到目前为止，已经对弹性光网络中的路由和频谱分配进行了全面的研究。但是，只有少数工作考虑了故障，保护和恢复的问题，以实现通过弹性光网络的无缝数据传输。在本文中，我们对几种不同的技术进行分类和审查，以保护流量需求免受故障的侵害，并针对多播流量需求提出了一种基于p周期的保护方法。采用疏导技术并将其并入基于保护的技术中，以根据业务需求提高频谱利用效率。我们将提出的算法与一些基于最新保护的方法进行了比较。从结果中可以明显看出，所提出的基于p周期的方法在资源利用率和执行时间方面优于其他方法，整理有助于减少频谱资源以及主要和备用资源。最后，我们讨论了一些重要的研究领域，其范围和与弹性光网络范例中基于保护和恢复的研究相关的挑战。