Elastic optical networks (EON) have been proposed to meet the network capacity and dynamicity challenges. Hardware and software resource optimization and re-configurability are key enablers for EONs. Recently, innovative multi-carrier transmission techniques have been extensively investigated to realize high capacity (Tb/s) flexible transceivers. In addition to standard telecommunication lasers, optical carrier generators based on optical frequency combs (OFC) have also been considered with expectations of reduced cost and inventory, improved spectral efficiency, and flexibility. A wide range of OFC generation techniques have been proposed in the literature over the past few years. It is imperative to summarize the state of the art, compare and assess these diverse techniques from a practical perspective. In this survey, we identify salient features of optical multicarrier generators, review and compare these techniques both from a physical and network layer perspective. OFC demultiplexing/filtering techniques have also been reviewed. In addition to transmission performance, the impact of such sources on the network performance and real-world deployment strategies with reference to cost, power consumption, and level of flexibility have also been discussed. Field trials, integrated solutions, and flexibility demonstrations are also reported. Finally, open issues and possible future directions that can lead to real network deployment are highlighted.

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A Survey of Optical Carrier Generation Techniques for Terabit Capacity Elastic Optical Networks

Low-latency orchestration for workflow-oriented service function chain in edge computing

A Survey of Reconfigurable Optical Networks

This paper proposes and investigates a reconfiguration policy of cloud and bandwidth resources in network function virtualization environments in which the network function virtualization infrastructure-point of presences are interconnected by an elastic optical network. The proposed policy is applied in dynamic traffic scenarios, it is based on virtual network function instances migrations and reconfiguration of optical circuits. The policy aims at minimizing the sum of three cost components: the cloud resource cost, the bandwidth cost, and the reconfiguration cost. The reconfiguration costs are characterized by the revenue loss of a network operator due to the bit loss occurring when the optical circuits are reconfigured. We formulate the optimization problem and because of its complexity we propose and investigate an effective heuristic. The achieved results show how the proposed heuristic allows, in typical traffic and network scenario, for a consistent cost reduction with respect to the solutions proposed in literature in which only the sum of cloud and bandwidth resource costs are considered and reconfiguration costs are not take into account.

Proposal and Investigation of a Reconfiguration Cost Aware Policy for Resource Allocation in Multi-Provider NFV Infrastructures Interconnected by Elastic Optical Networks

An important challenge in network virtualization is the process of assigning physical resources to virtual network requests, where virtual node resources represent the demands of IT capacities while virtual links are connected between pairs of virtual nodes. Due to their special characteristics, physical optical network infrastructures requires specific strategies to solve this problem, called virtual optical network embedding (VONE). This paper presents a survey on most relevant VONE schemes found in the literature. A discussion of important algorithmic aspects of this problem is presented, such as optical-layer restrictions, global performance metrics, and possible research directions. In addition, we propose a new taxonomy of VONE approaches, considering the type of optical networks, dynamic or static scenarios, and the optimization method.

A Survey on Algorithmic Aspects of Virtual Optical Network Embedding for Cloud Networks

The recent decade has witnessed an evolution toward virtualization of everything for the IT industry. Resources, from utility resources to networking components and functions, are abstracted as logical or virtual services. Virtualization results in elastic, agile, and automated resource provision, and facilitates the resource pricing in a pay-as-you-go model. Among this wave, the optical community has made parallel efforts in virtualizing resources in optical networks including both optical node and link resources. A virtualized optical network can not only seamlessly support automated resource provision, but also supply high-bandwidth any-to-any connectivity for network virtualization. In this paper, we overview the motivations and architecture for optical-based network virtualization. Among candidate optical networking paradigms, we argue that spectrum-sliced elastic optical path (SLICE) networks can be considered as a promising substrate choice, and study the key enabling problem, namely optical virtual network embedding over SLICE networks (OVNE-SLICE). We prove the NP-completeness of the OVNE-SLICE problem, and propose two mathematical models for this problem based on a concept named path-channel . The models are evaluated in our simulation, and compared with alternative models proposed in the literature.

Network Virtualization in Spectrum Sliced Elastic Optical Path Networks

Previously we looked at how a generalization of the Welch–Berlekamp could be used to efficiently list decode Reed-Solomon codes up to the Johnson bound of 1 − √ R fraction of errors. However, this still falls short of the list decoding capacity of 1 − R we hope to achieve. The main problem with Reed-Solomon codes is that because we have a large block length, we have to be able to handle a large number of different error patterns. To circumvent this we introduced Folded Reed-Solomon codes (FRS) which pack together the codewords into blocks. This decreases the block length, reducing the number of error patterns to handle, at the cost of increasing the alphabet size.

Zachary McNulty

Papers

Network Virtualization in Spectrum Sliced Elastic Optical Path Networks

CS294-226: Advances in Error-Correcting Codes