Software Defined Optical Networks (SDONs): A Comprehensive Survey (1511.04376v3)

Abstract: 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 (QoS). 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.

• The paper demonstrates how integrating SDN with optical networks enhances virtualization, resource management, and overall network agility.
• It employs methodologies such as impairment-aware virtual optical network embedding and hybrid control strategies to optimize performance.
• The survey outlines future research directions including protocol standardization, seamless hybrid operations, and energy-efficient orchestration across multi-domain networks.

Survey on Software Defined Optical Networks (SDONs)

The paper "Software Defined Optical Networks (SDONs): A Comprehensive Survey" by Thyagaturu et al. tackles the intricate field of Software Defined Networking (SDN) as applied to optical networks, encapsulating the trajectory from fundamental principles to the present amalgamation of SDN in the optical domain. Unlike conventional networks, optical networks, with their unique characteristics, present both significant challenges and profound capability enhancement avenues when integrated with SDN paradigms.

The survey comprehensively addresses three pivotal layers of SDN's architecture—namely the infrastructure, control, and application layers—while also considering network virtualization and orchestration of multi-layer and multi-domain networks. It primarily consolidates research efforts directed at adapting and optimizing SDN principles for optical network environments, elucidating the specific challenges arising from the integration of SDN with optical technologies.

The infrastructure layer covered in the survey discusses the adaptation of SDN principles to optical components such as Bandwidth Variable Transponders (BVTs) and Reconfigurable Optical Add-Drop Multiplexers (ROADMs). With significant emphasis on Network Virtualization (NV), the paper studies the impact of embedding virtual optical networks on a given physical infrastructure, highlighting advanced techniques including impairment-aware VON embedding and survivable network design in SDONs. These virtualization strategies provide robust solutions for maximizing resource utilization and ensuring high availability and reliability of services.

Control layer adaptations mark another crucial aspect, requiring OpenFlow protocol enhancements to manage optical-specific parameters and provide support for optical circuit and packet switching behaviors. Advances in PCE protocols and hybrid control strategies combining SDN with GMPLS facilitate optimal path calculations and network resource management across multi-domain SDONs, offering a nuanced look at collaborative approaches between varying network technologies.

On the application layer, SDON's capability to bolster Quality of Service (QoS) and manage networks dynamically is emphasized. Applications like video caching and traffic scheduling in optical networks clearly showcase how SDON drives efficiency and service reliability through centralized, adaptive control regimes. Additionally, energy efficiency emerges as a major theme, where SDN-driven strategies significantly lower power consumption in optical transmission without compromising performance.

The orchestration section discusses both vertical and horizontal multilayer orchestration frameworks, which are engineered to flexibly manage networking resources across multiple technology domains and organizational boundaries. These frameworks facilitate agile adaptations and seamless service integrations, further accentuating SDON's role as a transformative architectural model.

In conclusion, the survey indicates substantial progress in integrating optical networks with SDN principles, yet highlights enduring challenges, including standardization of protocols, seamless hybrid operations with non-SDN elements, and achieving energy-optimized operation. It advocates for further investigation into robust orchestration strategies spanning both multiple technologies and administrative domains, ensuring that SDONs evolve to meet burgeoning demands for high-capacity, reliable, and agile network infrastructures. The presented research directions underscore the necessity for collaborative, innovative efforts to harness the full potential of SDONs and usher in the next evolution in optical networking.