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This paper proposes, designs, and validates a filterless metro network employing bidirectional transmission over a single fiber. Transmission impairments, dominated by cross talk, are specifically estimated leveraging on what we believe to be novel closed-form expressions to determine optical reach, launch power, and number of supported cascaded nodes. Results show that extremely good transmission performance can be achieved and further improved when misalignment in spectrum allocation is configured among the two counter-propagating directions. This confirms that filterless metro networks employing bidirectional transmission over a single fiber represent an extremely attractive solution, particularly in the case of scarce fiber availability and when regulatory aspects impose a rent for any occupied fiber infrastructure. [ABSTRACT FROM AUTHOR]

Telecommunication networks are becoming the central linking institution of the Fourth Industrial Revolution. To cope with the associated capacity and connectivity challenges, transportation networks may explore the -neglected so far- remaining transmission bands in the second and third low attenuation windows of the optical fibre overcoming the C-band barrier. To assess the potential of optical multi-band transmission systems to upgrade a European Operator's network, we have developed a planning tool based on a routing engine that exploits a novel Physical Layer Aware, Routing, Modulation and Spectral Assignment algorithm. We considered unrepeatered transmission exploiting fibre amplifiers tailored to each transmission band. Taking into account the performance of close to commercialization fibre amplifier devices, we estimated the impact for the most detrimental effects in multi-band transmission like ASE accumulation, FWM and SRS. With the aid of this planning tool, we demonstrate the potential of multi-band systems to upgrade network capacity without compromising the connectivity between Core nodes, albeit new physical layer challenges. Nevertheless, it is shown that multi-band systems allow higher operational flexibility that may slow-down the need to deploy additional C-band fibres. Moreover, we have shown that the roll out of these multi-band systems could be planned in phases in order to limit first-day capital expenditure. [ABSTRACT FROM AUTHOR]

Fiber-optic multi-band transmission (MBT) aims at exploiting the low-loss spectral windows of single-mode fibers (SMFs) for data transport, expanding by $\sim\!11\times$ the available bandwidth of C-band line systems and by $\sim\!5\times$ C+L-band line systems’. MBT offers a high potential for cost-efficient throughput upgrades of optical networks, even in absence of available dark-fibers, as it utilizes more efficiently the existing infrastructures. This represents the main advantage compared to approaches such as multi-mode/-core fibers or spatial division multiplexing. Furthermore, the industrial trend is clear: the first commercial C $+$ L-band systems are entering the market and research has moved toward the neighboring S-band. This article discusses the potential and challenges of MBT covering the ITU-T optical bands O  $\rightarrow$  L. MBT performance is assessed by addressing the generalized SNR (GSNR) including both the linear and non-linear fiber propagation effects. Non-linear fiber propagation is taken into account by computing the generated non-linear interference by using the generalized Gaussian-noise (GGN) model, which takes into account the interaction of non-linear fiber propagation with stimulated Raman scattering (SRS), and in general considers wavelength-dependent fiber parameters. For linear effects, we hypothesize typical components’ figures and discussion on components’ limitations, such as transceivers,’ amplifiers’ and filters’ are not part of this work. We focus on assessing the transmission throughput that is realistic to achieve by using feasible multi-band components without specific optimizations and implementation discussion. So, results are meant to address the potential throughput scaling by turning-on excess fiber transmission bands. As transmission fiber, we focus exclusively on the ITU-T G.652.D, since it is the most widely deployed fiber type worldwide and the mostly suitable to multi-band transmission, thanks to its ultra-wide low-loss single-mode high-dispersion spectral region. Similar analyses could be carried out for other single-mode fiber types. We estimate a total single-fiber throughput of 450 Tb/s over a distance of 50 km and 220 Tb/s over regional distances of 600 km: $\sim\!10\times$ and 8× more than C-band transmission respectively and $\sim\!2.5\times$ more than full C+L. [ABSTRACT FROM AUTHOR]

The migration of DataCenters into Metropolitan Area Networks creates new challenges which include the need for rapid service provisioning and recovery and new, cost-effective, connectivity schemes. Here we propose and demonstrate a truly dynamic transportation platform tailored for a metro network. The novelty of the proposed architecture is that the dynamic data-plane exploits available commercial PON technology while the dynamic control-plane is SDN-enabled using OpenFlow/Netconf. The dynamic operation of the platform in several interesting scenarios is demonstrated on an experimental test-bed. [ABSTRACT FROM AUTHOR]

Simplified, closed-form, mathematical expressions for four wave mixing (FWM) in coherent optical systems are derived. FWM is an important limitation in both coherent OFDM (CO-OFDM) and Nyquist-WDM systems. The effect is also important in networks deploying dispersion shifted fiber and/or based on very narrow channel spacing. In this work, 1) we improve the accuracy of the formalism in CO-OFDM systems by taking into account not only the contribution due to the power of the central carrier but also the contribution due to the spectral flanks as well as the guard band between channels and 2) we extend the formalism to work for flexgrid systems. The derived expressions can be used for a quick estimation of system performance and/or can be incorporated in routing algorithms that account for physical layer effects. The formalism for flexgrid systems is estimating the power of FWM with improved accuracy compared to existing models in the literature so it can be a key asset in dynamic resource allocation operations. Finally, the derived expressions are valid for both, uncompensated and dispersion managed systems. [ABSTRACT FROM PUBLISHER]

The switchless elastic rate node (SERANO) is an elastic optical network block architecture facilitating reduction in network cost and blocking due to spectral fragmentation while extending the capacity-reach product in translucent optical networks. We present an analytical mathematical method for minimizing the number of transceivers that are solely used to construct this block, albeit a finite blocking probability. Moreover, based on a realistic traffic matrix and making use of a networking planning tool, we deduce a SERANO's block dimension for BT's national backbone network. Finally, we estimate the conditions under which the cost of a SERANO block is lower to the corresponding electronic switch for providing important networking functions like 3R regeneration, defragmentation, and network reoptimization. [ABSTRACT FROM PUBLISHER]

Many telecom operators are deploying their own cloud infrastructure with the two-fold objective of providing cloud services to their customers and enabling network function virtualization. In this article we present an architecture we call SHINE, which focuses on orchestrating cloud with heterogeneous access and core networks. In this architecture intra and inter DC connectivity is dynamically controlled, maximizing the overall performance in terms of throughput and latency while minimizing total costs. The main building blocks are: a future-proof network architecture that can scale to offer potentially unlimited bandwidth based on an active remote node (ARN) to interface end-users and the core network; an innovative distributed DC architecture consisting of micro-DCs placed in selected core locations to accelerate content delivery, reducing core network traffic, and ensuring very low latency; and dynamic orchestration of the distributed DC and access and core network segments. SHINE will provide unprecedented quality of experience, greatly reducing costs by coordinating network and cloud and facilitating service chaining by virtualizing network functions. [ABSTRACT FROM PUBLISHER]

As traffic demands become more uncertain and newer services continuously arise, novel network elements are needed to provide more flexibility, scalability, resilience and adaptability to today's optical networks. Considering these requirements, within the European project IDEALIST the investigation of elastic optical networks is undertaken with special focus on next generation optical node architectures. As an evolution of existent ROADMs and OXCs, these optical nodes will establish a new paradigm in which the network requirements will be efficiently addressed considering various emerging dimensions. In this article, we describe the drivers, architectures, and technologies that will enable these novel optical nodes. In addition, multivendor traffic interoperability, optical defragmentation, and node cascadability are also described as considerations in the node design. [ABSTRACT FROM PUBLISHER]

In this work we detail the strategies adopted in the European research project IDEALIST to overcome the predicted data plane capacity crunch in optical networks. In order for core and metropolitan telecommunication systems to be able to catch up with Internet traffic, which keeps growing exponentially, we exploit the elastic optical networks paradigm for its astounding characteristics: flexible bandwidth allocation and reach tailoring through adaptive line rate, modulation formats, and spectral efficiency. We emphasize the novelties stemming from the flex-grid concept and report on the corresponding proposed target network scenarios. Fundamental building blocks, like the bandwidth-variable transponder and complementary node architectures ushering those systems, are detailed focusing on physical layer, monitoring aspects, and node architecture design. [ABSTRACT FROM PUBLISHER]

This paper proposes HYbriD long-Reach fiber Access network (HYDRA), a novel network architecture that overcomes many limitations of the current WDM/TDMPON approaches leading to significantly improved cost and power consumption figures. The key concept is the introduction of an active remote node that interfaces to end-users by means of the lowest cost/power consumption technology (short-range xPON, wireless, etc.) while on the core network side it employs adaptive ultra-long reach links to bypass the metropolitan area network. The scheme leads to a higher degree of node consolidation and access-core integration. We demonstrate that HYDRA can achieve very high performance based on mature component technologies ensuring very low cost end-user terminals, reduced complexity, and high scalability. [ABSTRACT FROM AUTHOR]

In this article, we present an algorithm for clustering a mesh network implementing the Clustering Architecture of Nodes in Optical Networks (CANON). In order to evaluate the impact of the resulting clustering solutions on actual network efficiency, specific cost criteria are used. [ABSTRACT FROM PUBLISHER]

The explosion of current demand has brought the contemporary multidomain core network paradigm to its limit. In the quest for new approaches that exploit recent developments in optical technology, a novel network architecture that obviates most of the expensive and loss-prone centralized all-optical switches is described in this work. It is based on clustered architecture for nodes in optical networks and features a reconciliation between dynamic resource allocation and guaranteed end-to-end network performance in a multidomain network. This article enhances the distributed, collision-free slot aggregation inside domains of clustered core nodes with dynamic switching of slots/frames between the domains. Thus, it can support dynamic sub-wavelength allocations between network domains, using standard burst-switching techniques. This extends the high efficiency and multiplexing gain into the inter-domain network even under highly bursty traffic. It features both low-cost optical add/drop edge nodes exploiting WDM transmission and agile and modular centralized electro-optical switches that are presented in conjunction with the overall network architecture. Its performance exhibits very low burst loss probability traded for a higher but tolerable and bounded delay. [ABSTRACT FROM AUTHOR]

The manner and exact timing of the evolution of the widely used DWDM infrastructure to a transparent optical network will be judged on economic circumstances and network performance. In this context this article elaborates on a methodology developed within the Project 1ST NOBEL,¹ for integrating cost functions and other design constraints into the planning of a DWDM network while considering this evolution perspective to a transparent optical network. This systematic approach builds upon the experience of static network design and is sub- stantiated by specific examples in this article. [ABSTRACT FROM AUTHOR]

This article presents information on several articles published in the November 1, 2005 issue of the "IEEE Communications Magazine." The first article by Nageswara S.V. Rao is titled "UltraScienceNet: Network Testbed for Large-Scale Science Applications." This article presents the key aspects of the U.S. Department of Energy's experimental testbed for developing networking technologies for next-generation large-scale scientific applications. The second article by Ilia Baldine is titled "JumpStart Deployments in Ultra High Performance Optical Networking Testbeds." This work details developments in the JumpStart concept for architectures and protocols for use in various ultra-high-performance optical testbeds. The third article, "In-Field Evaluation of a Managed IP/MPLS over WDM Provisioning Solution" by Fotis Karayannis, addresses various aspects of multilayer networking and associated challenges in achieving on-demand bandwidth provisioning and resource/restoration management. The fourth article is titled "Global Seamless Network Demonstrator: A Comprehensive ASON/GMPLS Testbed," by Hans-Martin Foisel. This work details Deutsche Telekom AG's activities in setting up various comprehensive ASON/GMPLS network demonstrators.

Presents an introduction to the articles published in the August 2005 issue of the journal "IEEE Optical Communications."