Software Defined Optical Networks (SDONs): A Comprehensive Survey

The emerging software defined networking (SDN) paradigm separates the data plane from the control plane and centralizes network control in an SDN controller. Applications interact with controllers to implement network services, such as network transport with quality of service. SDN facilitates the virtualization of network functions so that multiple virtual networks can operate over a given installed physical network infrastructure. Due to the specific characteristics of optical (photonic) communication components and the high optical transmission capacities, SDN-based optical networking poses particular challenges, but holds also great potential. In this article, we comprehensively survey studies that examine the SDN paradigm in optical networks; in brief, we survey the area of software defined optical networks (SDONs). We mainly organize the SDON studies into studies focused on the infrastructure layer, the control layer, and the application layer. Moreover, we cover SDON studies focused on network virtualization, as well as SDON studies focused on the orchestration of multilayer and multidomain networking. Based on the survey, we identify open challenges for SDONs and outline future directions.

I. Introduction

At least a decade ago [1] it was recognized that new network abstraction layers for network control functions needed to be developed to both simplify and automate network management. Software Defined Networking (SDN) [2]–[4] is the design principle that emerged to structure the development of those new abstraction layers. Fundamentally, SDN is defined by three architectural principles [5], [6]: the separation of control plane functions and data plane functions, the logical centralization of control, and programmability of network functions. The first two architectural principles are related in that they combine to allow for network control functions to have a wider perspective on the network. The idea is that networks can be made easier to manage (i.e., control and monitor) with a move away from significantly distributed control. A tradeoff is then considered that balances ease of management arising from control centralization and scalability issues that naturally arise from that centralization.