https://www.cba.upc.edu/downloads/category/11-articles?download=355:[ARTICLE]A_survey_on_physical_layer_impairments_aware_routing_and_wavelength_assignment_algorithms_in_optical_networks.pdf

A survey on physical layer impairments aware routing and wavelength assignment algorithms in optical networks

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.

Software Defined Optical Networks (SDONs): A Comprehensive Survey

In WDM optical networks, the physical layer impairments (PLIs) and their significance depend on network type-opaque, translucent, or transparent; the reach-access, metro, or core/long-haul; the number and type of network elements-fiber, wavelengths, amplifiers, switching elements, etc.; and the type of applications-real-time, non-real time, missioncritical, etc. In transparent optical networks, PLIs incurred by non-ideal optical transmission media accumulate along an optical path, and the overall effect determines the feasibility of the lightpaths. If the received signal quality is not within the receiver sensitivity threshold, the receiver may not be able to correctly detect the optical signal and this may result in high bit-error rates. Hence, it is important to understand various PLIs and their effect on optical feasibility, analytical models, and monitoring and mitigation techniques. Introducing optical transparency in the physical layer on one hand leads to a dynamic, flexible optical layer with the possibility of adding intelligence such as optical performance monitoring, fault management, etc. On the other hand, transparency reduces the possibility of client layer interaction with the optical layer at intermediate nodes along the path. This has an impact on network design, planning, control, and management. Hence, it is important to understand the techniques that provide PLI information to the control plane protocols and that use this information efficiently to compute feasible routes and wavelengths. The purpose of this article is to provide a comprehensive survey of various PLIs, their effects, and the available modeling and mitigation techniques. We then present a comprehensive survey of various PLI-aware network design techniques, regenerator placement algorithms, routing and wavelength assignment algorithms, and PLI-aware failure recovery algorithms. Furthermore, we identify several important research issues that need to be addressed to realize dynamically reconfigurable next-generation optical networks. We also argue the need for PLI-aware control plane protocol extensions and present several interesting issues that need to be considered in order for these extensions to be deployed in real-world networks.

Physical layer impairment aware routing (PLIAR) in WDM optical networks: issues and challenges

We demonstrate the use of impairment constraint routing for performance engineering of transparent metropolitan area optical networks. Our results show the relationship between blocking probability and different network characteristics such as span length, amplifier noise figure, and bit rate, and provide information on the system specifications required to achieve acceptable network performance.

Performance engineering of metropolitan area optical networks through impairment constraint routing

This paper presents solutions towards an efficient and intelligent network infrastructure for Grid services, taking advantage of recent developments in optical-networking technologies. Two lambda-Grid network architectures based on extensions to existing wavelength-switched network infrastructure are discussed. These network solutions aim to provide a user-centric Grid environment, specifically for data-intensive and e-science applications. Furthermore, a novel solution towards an intelligent and ubiquitous photonic-Grid network based on optical burst switching (OBS) is proposed. The proposed solution utilizes active optical burst-switched routers and advanced protocols in order to provide a programmable photonic-Grid network infrastructure for evolving data-intensive and emerging Grid applications.

Dynamic optical-network architectures and technologies for existing and emerging grid services

WDM optical communication systems are evolving from simple point-to-point links to complex network architectures. In wavelength routed networks switching is performed through optical add/drop multiplexer (OADM) and optical cross-connect (OXC) nodes. These nodes provide provisioning capabilities as well as protection and restoration at the optical layer. Routing and management of the traffic demands are applied through the generalised multiprotocol label switching (GMPLS) a control plane offering intelligence at the optical layer. A central subject of debate has been the comparison of optical and electrical switching technologies, however transparent solutions offer attractive features associated with reduced unnecessary optoelectronic conversions supporting transparent networks with reduced capital and operational cost. A number of different OADM and OXC architectures based on various technologies have been proposed to date. A detailed discussion on the different architecture and technology choices supporting a variety of features are given and specific design and implementation examples are analysed. The impact of impairments introduced by transparent elements present in the network, such as OADM and/or optical switches, is discussed and optimised solutions introducing low penalties proposed. In addition, the use of novel modulation formats improving the concatenation performance of such elements is covered.

http://ieeexplore.ieee.org/iel5/8924/28282/01264574.pdf

Optical add/drop multiplexers and optical cross-connects for wavelength routed networks

This article has focused on optical networks using WDM to provide broadband network solutions with increased functionality, capacity, and reach. The building blocks in this type of networks, i.e., OADMs and OXCs, have been discussed in detail. The different architectures and technology options used in these types of nodes have been investigated. A comparison between WS and BS OADM architectures has been given, while OXCs have been classified into opaque and transparent. The WS and B&S transparent OXC architectures have been discussed in detail, and the various technology options in terms of optical switching have been covered. The system performance of OADMs and OXCs including their cascadability has been analyzed in terms of OSNR, crosstalk, amplifier transients, and filter concatenation effects.

Broadband building blocks [optical networks]

We report on a wavelength converter based on dual pump wave mixing in an 1-mm-long bulk semiconductor optical amplifier. Very high conversion efficiency (more than 0 dB) and signal-to-background-noise ratio (SBR) (16 dB), for large down- or up-wavelength shifts (30 mn) has been achieved using parallel polarized pumps with low optical power (-13 dBm). Orthogonal polarized pumps result in worse performance, having the advantage of polarization insensitivity for small wavelength spacing between them. The converter operates in a fixed input-tunable output or a tunable input-fixed output mode of operation. In each mode, the measured SBR is almost independent of the wavelength shift for either up- or down-conversion.

Performance of a reconfigurable wavelength converter based on dual-pump-wave mixing in a semiconductor optical amplifier

A comprehensive analysis and survey of the optical performance monitoring (OPM) is provided towards the deployment of translucent/transparent optical networks. OPM applications and technologies are reviewed for the different stages of the optical network life cycle: planning and provisioning, impairment mitigations, maintenance and failure location. Recommendations for the most relevant OPMs required to be integrated in translucent/transparent optical networks are provided.

I. Zacharopoulos

Papers

Performance engineering of metropolitan area optical networks through impairment constraint routing

Optical add/drop multiplexers and optical cross-connects for wavelength routed networks

Broadband building blocks [optical networks]

Performance of a reconfigurable wavelength converter based on dual-pump-wave mixing in a semiconductor optical amplifier

Optical performance monitoring for translucent/transparent optical networks