**5. Conclusions**

Network virtualization has emerged as an enabling technology for cloud computing services. Such services would push even further the limits on bandwidth utilization, where flexible‐ grid optical networks will be the key to increase the network capacity of actually deployed optical networks. As a result, a new area of research focused on network virtualization over flexible‐grid networks has emerged.

On such area, the research efforts focus on three main lines: design of flexible and virtualized devices, definition of network architectures and virtual network allocation algorithms.

In this chapter, a survey on the virtual network allocation algorithms over flexible‐grid net‐ works has been presented along with a classification of all possible proposals of algorithms by means of taxonomy. Such classification allowed the identification of several aspects that must be further investigated in the area:


## **Acknowledgements**

Financial support from CONICYT through the Fondecyt Project 1130388 and 11140386 and the PhD Scholarship,CONICYT‐PCHA/Doctorado Nacional/2015‐21150525 is gratefully acknowledged.
