Showing papers on "10G-PON published in 2013"

Software-defined optical networks technology and infrastructure: Enabling software-defined optical network operations [invited]

Abstract: Software-defined networking (SDN) enables programmable SDN control and management functions at a number of layers, allowing applications to control network resources or information across different technology domains, e.g., Ethernet, wireless, and optical. Current cloud-based services are pushing networks to new boundaries by deploying cutting edge optical technologies to provide scalable and flexible services. SDN combined with the latest optical transport technologies, such as elastic optical networks, enables network operators and cloud service providers to customize their infrastructure dynamically to user/application requirements and therefore minimize the extra capital and operational costs required for hosting new services. In this paper a unified control plane architecture based on OpenFlow for optical SDN tailored to cloud services is introduced. Requirements for its implementation are discussed considering emerging optical transport technologies. Implementations of the architecture are proposed and demonstrated across heterogeneous state-of-the-art optical, packet, and IT resource integrated cloud infrastructure. Finally, its performance is evaluated using cloud use cases and its results are discussed.

Optical interconnection networks in data centers: recent trends and future challenges

Abstract: Warehouse-scale data center operators need much-higher-bandwidth intra-data center networks (DCNs) to sustain the increase of network traffic due to cloud computing and other emerging web applications. Current DCNs based on commodity switches require excessive amounts of power to face this traffic increase. Optical intra-DCN interconnection networks have recently emerged as a promising solution that can provide higher throughput while consuming less power. This article provides an update on recent developments in the field of ultra-highcapacity optical interconnects for intra-DCN communication. Several recently proposed architectures and technologies are examined and compared, while future trends and research challenges are outlined.

Software defined optical networks technology and infrastructure: Enabling software-defined optical network operations

Abstract: A control plane architecture based on OpenFlow for optical SDN is introduced. Requirements for its implementation are discussed considering emerging optical transport technologies. Two implementations of the architecture and results on their performance are reported.

Radio-Over-Fiber Access Architecture for Integrated Broadband Wireless Services

Abstract: This paper introduces two radio-over-fiber (RoF) architectures for the future broadband optical-wireless access network-all-band RoF and band-mapped 60-GHz RoF that can be integrated in ultra-dense wavelength division multiplexing passive optical network (UDWDM-PON). Legacy wireless services and multi-gigabit millimeter-wave (mm-wave) applications are integrated and delivered simultaneously under one shared infrastructure. With centralized system control and signal processing, the proposed systems provide cost-effective and protocol-transparent solutions for the next-generation multi-service bundle in heterogeneous networks (HetNets). In the all-band RoF network where wireless services are kept at their original carrier frequencies, Wi-Fi, WiMAX, and 60-GHz high-speed mm-wave services are transmitted based on subcarrier multiplexing (SCM) and dual-wavelength heterodyne beating techniques in avoidance of optical filters and large-bandwidth optoelectronic components. In the indoor environment, the band-mapped mm-wave RoF design is illustrated with real-time analog television signal, Wi-Fi, and high-speed digital baseband data-all of which are transmitted over unified optical and air links. By mapping various wireless signals into 60-GHz sub-bands, the novel architecture achieves higher spectral efficiency and lower power consumption.

Advanced wireless and optical technologies for small-cell mobile backhaul with dynamic software-defined management

Abstract: This article discusses novel wireless and optical technologies to address the radical new challenges of small cell mobile backhaul (MBH). Specifically, we examine 60 GHz and 70-80 GHz millimeter-wave technologies for high-capacity last mile and pre-aggregation backhaul, and orthogonal frequency-division multiple access passive optical networks as the optical technology complement for enabling flexible cost-efficient hybrid backhaul coverage. Flexible high-capacity hybrid millimeter wave/optical MBH network operation is next verified via network simulations in the context of a demanding, urban small-cell backhaul application. Finally, a novel software defined networking tool called the backhaul resource manager is introduced for automated dynamic resource provisioning and capacity-aware path computation that improves fairness, network utilization and end-to-end user quality of experience. The introduction of the novel wireless, optical, and software-defined technologies thus has the potential to truly revolutionize the future MBH network.

Power Saving Techniques and Mechanisms for Optical Access Networks Systems

Abstract: This tutorial paper provides an overview of studies and works to address the power saving issue in the optical access network (OAN), which typically comprises passive optical networks (PONs) and Ethernet aggregators (EAs). First, it describes techniques to reduce the power consumption of the optical network unit in each subscriber's home. It outlines methods standardized in ITU-T such as “dozing” and “cyclic sleep,” as well as elucidating other techniques. Next, power saving at the optical line terminal (OLT)/EA side is focused. The energy-aware operation of link aggregation and its application to OAN are described to decrease power consumed by the EAs used with time-division multiaccess (TDMA) PONs. Finally, a selective OLT sleep technique is introduced for the next-generation wavelength division multiplexing (WDM)-TDMA PON with wavelength routing technologies.

The prospect of inter-data-center optical networks

Abstract: Mega data centers and their interconnection networks have drawn great attention in recent years because of the rapid public adoption of cloud-based services. The unprecedented amount of data that needs to be communicated between data centers imposes new requirements and challenges to inter-data-center optical networks. In this article, we discuss the traffic growth trends and capacity demands of Google?s inter-data-center network, and how they drive the network architectures and technologies to scale capacities and operational ease on existing fiber plants. We extensively review recent research findings and emerging technologies, such as digital coherent detection and the flexgrid dense wavelength-division multiplexed channel plan, and propose practical implementations, such as C+L-band transmission, packet and optical layer integration, and a software-defined networking enabled network architecture for both capacity and operational scaling. In addition, we point out a few critical areas that require more attention and research to improve efficiency and flexibility of an inter-data-center optical network: optical regeneration, data rate mismatch between Ethernet and optical transport, and real-time optical performance monitoring.

Design and optimization of fiber optic small-cell backhaul based on an existing fiber-to-the-node residential access network

Abstract: As the number of wireless users and per-user bandwidth demands continue to increase, both the vendor and carrier communities agree that wireless networks must evolve toward more dense deployments. So-called heterogeneous networks are a commonly proposed evolution, whereby existing macrocellular networks are supplemented with an underlay of small cells. The placement of new small-cell sites is typically determined based on various location-dependent factors such as radio propagation calculations, user densities, and measurements of congestion and demand. The backhaul network, which can account for a significant portion of the total cost of the deployment, is then designed in reaction to the placement of small cells. In contrast, we describe a design method that first considers the locations of existing fibered and powered facilities that might be leveraged to provide inexpensive backhaul. Naturally, such a method is only feasible if the carrier has a legacy local fiber network. This article describes an efficient fiber backhaul strategy for a small-cell network, which leverages facilities associated with an existing FTTN residential access network. Once potential small-cell sites are determined from among all FTTN remote terminals, optimization techniques are used to choose the most efficient subset of sites for maximum coverage, and to design the fiber backhaul architecture.

Virtual topology mapping in elastic optical networks

Abstract: Virtualization improves the efficiency of networks by allowing multiple virtual networks to share a single physical network's resources. Next-generation optical transport networks are expected to support virtualization by accommodating multiple virtual networks with different topologies and bit rate requirements. Meanwhile, Optical Orthogonal Frequency-Division Multiplexing (OOFDM) is emerging as a viable technique for efficiently using the optical fiber's bandwidth in an elastic manner. OOFDM partitions the fiber's bandwidth into hundreds or even thousands of OFDM subcarriers that may be allocated to services. In this paper, we consider an OOFDM-based optical network and formulate a virtual network mapping problem for both static and dynamic traffic. This problem has several natural applications, such as e-Science, Grid, and cloud computing. The objective for static traffic is to maximize the subcarrier utilization, while minimizing the blocking ratio is the aim for dynamic traffic. Two heuristics are proposed and compared. Simulation results are presented to demonstrate the effectiveness of the proposed approaches.

DSP-based optical access approaches for enhancing NG-PON2 systems

Abstract: Motivated by recent progress in next-generation PON2, or NG-PON2, standardization, this article reviews digital signal processing technologies to further enhance NG-PON2 systems by realizing flexible and cost-effective optical access network deployments. First, flexible speed upgrades by DSP-enabled advanced modulation and multiplexing approaches are described, followed by a consideration of cost-performance trade-offs. Next, reach extension using DSP-based digital coherent reception and impairment compensation is overviewed. Finally, as a future goal, access network virtualization with reconfigurable optical line terminals and optical network units is discussed.

Virtualization in optical networks from network level to hardware level [invited]

Abstract: Elastic optical networking is attracting much attention as a promising solution to achieve spectrum-efficient transport of higher data rates at 100 Gbits/s and beyond. If we draw an analogy to virtualization in cloud computing, it can be seen as network level resource virtualization of optical networks where spectrum resources in optical links are segmented as shareable resources and adaptively aggregated to create a wide variety of optical channels (OChs). In this paper, we discuss the benefits of introducing virtualization into the optical domain from the viewpoints of the network level and the hardware level. In elastic optical networks, a frequency slot through which an OCh is transported and the OCh itself are explicitly decoupled. While the adaptability in the frequency slot is brought about by bandwidth variable wavelength-selective switches, the adaptability in an OCh is yielded by digital coherent technology that is employed in transponders and regenerators. It is emphasized that in order to achieve transponders and regenerators that accommodate heterogeneous traffic demands in an economical manner, simply being adaptive is not enough, and being shareable is essential. We refer to this concept as hardware level virtualization. As examples, we describe a multiflow transponder and an elastic regenerator with results that show proof of concept. Based on the hardware virtualization concept, we propose an elastic optical transport system (EOTS) architecture that enables cost- and energy-efficient IP traffic offloading to the optical domain and improves programmability and automation of optical networks.

Fault-tolerant virtual network mapping to provide Content Connectivity in optical networks

Abstract: We define Content Connectivity as the reachability of every content from any point of an optical network. We propose a scheme for virtual network mapping and content placement to ensure content connectivity after failures.

Exploiting PONs for mobile backhaul

Abstract: The growing popularity of mobile data services necessitates a rapid rise in network capacity not only on the air interface to the end user, but also in the backhaul network. The latter is quite important for the mobile operator business model, affecting capital investment, operational expenses, service deployment, and customer experience. Fiber infrastructure is inevitably the only long-term solution, and the deployment of passive optical networks presents an opportunity for a cost-effective, scalable, and future-proof solution. In this article we investigate the use of PONs for mobile backhaul and propose a resource allocation framework building on the efficiency of PONs to share resources, dynamically allocate bandwidth in real time, and enhance efficiency by improved statistical multiplexing. The main objective of this work is to exploit existing standardized technologies, and provide design and deployment guidelines regarding PON MAC operation, enabling a gradual and future-safe infrastructure upgrade of mobile backhaul systems.

Hybrid Optical Wireless Access Networks

Abstract: This paper describes a dynamic reconfiguration algorithm for a hybrid fiber wireless network, which takes advantage of dynamic reconfiguration in WDM based optical networks to provide bandwidth on the fly. The WDM technique for optical networks allows network operators to extend the existing capacity of passive optical networks manifolds. However presently, WDM networks were used mostly in long haul backbone networks and recently have been put to use in metropolitan networks (MAN). But till now not much work has been done on use of WDM networks in MAN. We use wireless technology to solve the Last mile problem of WDM networks. Wireless networks on the other hand are always constrained by need of bandwidth and we use WDM based optical networks to provide that. So both network technologies complement each other. Our proposed approach allows providing bandwidth on demand. It also allows for service differentiation by service providers, and sharing of infrastructure by several service providers.

Elastic optical networks: The global evolution to software configurable optical networks

Abstract: Worldwide operator deployment of high-speed 100G coherent optical networks is currently underway. To ensure a competitive solution offering significant performance improvements to cope with the ever-increasing traffic demand, a novel network concept has been proposed for improved resource utilization based on “elasticity”; specifically, the ability to make a number of previously fixed transmission parameters tunable, for example optical data rate or channel spacing. The benefits are numerous, including increased network capacity, lower cost per bit, and improved energy efficiency and scalability. In this paper, we review the work carried out within the Cooperation for a Sustained European Leadership in Telecommunications (CELTIC) Elastic-Optical NETwork (EO-Net) project towards advancing the state of software-configurable optical networking. We identify the key building blocks for enabling elastic optical networks to provide desired performance improvements over static optical networks. We examine the design of elastic transponders capable of data rate adaptation, interfaces between client packet devices and transponders supporting flexible traffic aggregation, and associated algorithms for traffic grooming and routing. We also perform network cost/energy analyses. Finally, we review the experimental demonstration of such elastic functionalities.

Role of optical network virtualization in cloud computing [invited]

Abstract: New and emerging Internet applications are increasingly becoming high-performance and network-based, relying on optical network and cloud computing services. Due to the accelerated evolution of these applications, the flexibility and efficiency of the underlying optical network infrastructure as well as the cloud computing infrastructure [i.e., data centers (DCs)] become more and more crucial. In order to achieve the required flexibility and efficiency, coordinated provisioning of DCs and optical network interconnecting DCs is essential. In this paper, we address the role of high-performance dynamic optical networks in cloud computing environments. A DC as a service architecture for future cloud computing is proposed. Central to the proposed architecture is the coordinated virtualization of optical network and IT resources of distributed DCs, enabling the composition of virtual infrastructures (VIs). During the composition process of the multiple coexisting but isolated VIs, the unique characteristics of optical networks (e.g., optical layer constraints and impairments) are addressed and taken into account. The proposed VI composition algorithms are evaluated over various network topologies and scenarios. The results provide a set of guidelines for the optical network and DC infrastructure providers to be able to effectively and optimally provision VI services to users and satisfy their requirements.

Towards networks of the future: SDN paradigm introduction to PON networking for business applications

Abstract: The paper is devoted to consideration of an innovative access network dedicated to B2B (Business To Business) applications. We present a network design based on passive optical LAN architecture utilizing proven GPON technology. The major advantage of the solution is an introduction of SDN paradigm to PON networking. Thanks to such approach network configuration can be easily adapted to business customers' demands and needs that can change dynamically. The proposed solution provides a high level of service flexibility and supports sophisticated methods allowing user traffic forwarding in effective way within the considered architecture.

A Hybrid Scalable Peer-to-Peer IP-Based Multimedia Services Architecture in Ethernet Passive Optical Networks

Abstract: Peer-to-peer (P2P) applications such as P2P video streaming and internet video calling have gained tremendous popularity and are expected to be vastly increasing in the next few years. However, low-cost large-scale video services have remained an intangible goal. The ethernet passive optical network (EPON) is being regarded as one of the promising for next-generation optical access solutions in the access networks attempt to tackle this problem but facing a major challenge to offer scalable large-scale video services. Therefore, in this paper, we propose an architecture which combines the advantages of EPON and P2P architecture to provide scalable Internet Protocol delivery multimedia services and improve quality-of-services. In the proposed architecture, we design new optical network unit (ONU) mechanisms, which support traffic redirection communication among ONUs in combination with caching. Thus, it can reduce the resource consumption and add extra downstream bandwidth at the optical line terminal since the intra-PON traffic is not necessary to be buffered and scheduled in the downstream direction. Finally, we propose a “Redirect” dynamic bandwidth allocation scheme, which can support intra-PON traffic redirection and intertraffic bandwidth allocation. Simulation results have shown that our proposed architecture can improve the overall QoS in terms of end-to-end delay, jitter, system throughput, fairness, and packet dropping rate.

Cognitive dynamic optical networks

Abstract: Cognitive networks are a promising solution for the control of heterogeneous optical networks. We review their fundamentals as well as a number of applications developed in the framework of the EU FP7 CHRON project.

Design of cost-optimal passive optical networks for small cell backhaul using installed fibers [invited]

Abstract: With the recent popularity of mobile data devices, the demand for mobile data traffic has grown rapidly as never before. Hence, service providers are trying to come up with cost-effective solutions to battle this ever increasing demand for bandwidth in their cellular networks. Deployment of a denser heterogeneous network, with a large number of small cells, has been identified as an effective strategy not only to satisfy this unabated growth in mobile data traffic but also to facilitate ubiquitous wireless access. While the cost associated with on-site small cell equipment is low in comparison with a typical macro cell, deployment of small cells opens a new set of challenges, especially in relation to expenditures and capacity requirements associated with the backhaul. In this paper we discuss an efficient small cell backhauling strategy that leverages existing fiber resourcesin a cost-optimal manner. In particular, we formulate an optimization framework for planning a cost-minimized backhaul for a small cell network, which is based on the deployment of passive optical networks on top of the existing infrastructure. We demonstrate the effectiveness of our method by using our optimization framework to design a cost-optimal backhaul for a small portion of a realistic backhaul network. Our results show that in comparison to the typical point-to-point fiber backhauling approach, our technique can halve the costs associated with small cell backhaul deployment.

Architecture and applications of a versatile small-cell, multi-service cloud radio access network using radio-over-fiber technologies

Abstract: Small-cell systems based on cloud radio access network (cloud-RAN) architecture have been proposed as promising solutions to meet the ever-increasing capacity demand of the next-generation wireless access networks. By centralizing the processing power to reduce the complexity of conventional cell sites, the cloud-RAN architecture is ideal for large-scale small-cell system at reduced capital and operational expenses. However, high-speed, flexible, and scalable backhaul links between the centralized baseband processing unit (BBU) and the remote antenna units (RAUs) are required to support the high throughput of the small-cell cloud-RANs, and the conventional approaches are based on digital baseband signal transmission in the backhaul links. In this paper, we propose a novel multi-service small-cell wireless access architecture based on radio-over-fiber (RoF) technologies. By utilizing analog radio frequency (RF) signal transmission in the optical backhaul links, the design of RAUs can be further simplified. In addition, by combing RoF with optical wavelength division multiplexing (WDM) techniques, multiple bands, multiple services and multiple operators can coexist in a shared optical infrastructure without interference. To demonstrate the proposed system, two-operator coexistence in a shared small-cell cloud-RoF access network is implemented in an in-building testbed by using off-the-shelf optoelectronic components and commercialized WiMAX base stations and clients. In addition, the feasibility of delivering both conventional wireless services and future-proof high-RF-band services (millimeter-wave band) is also demonstrated in the proposed multi-service small-cell cloud-RoF access systems.

An XG-PON module for the NS-3 network simulator

Abstract: 10-Gigabit-capable Passive Optical Network (XG-PON), one of the latest standards of optical access networks, is regarded as one of the key technologies for future Internet access networks. In this paper, we propose and discuss the design and implementation of an XG-PON module for the NS-3 network simulator. The aim is to provide a standards-compliant, configurable, and extensible module that can simulate XG-PON with reasonable speed and can support a wide range of research topics. These include analysing and improving the performance of XG-PON, studying the interactions between XG-PON and the upper-layer protocols, and investigating its integration with various wireless networks.

First OpenFlow-based software-defined λ-flow architecture for flex-grid OFDMA mobile backhaul over passive optical networks with filterless direct detection ONUs

Abstract: We demonstrate the first software-defined OpenFlow1.0-based flex-grid λ-flow architecture enabling 150Mb/s per-cell OFDMA MBH overlays onto bidirectional 10Gb/s PON, without any ONU-side optical filtering, amplification, or coherent detection over 20km SSMF and 1:64 passive split.

Design of cellular backhaul topology using the FSO technology

Abstract: The increasing number of mobile devices and high-speed services accelerate the growth of traffic in cellular backhaul networks. The traditional technologies used in the backhaul, copper, radio links and optical fibers, either cannot offer high data-rate, or are expensive. In this paper, we propose mixed integer programming models to facilitate upgrading the cellular backhaul using the free space optical (FSO) technology, a cost-effective and high-bandwidth solution. Since the optical signal is transmitted along line-of-sight and FSO links are sensitive to weather conditions, we incorporate mirrors in the models to provide alternative paths for pairs of FSO nodes without line-of-sight, and increase the path diversity to enhance the resilience. Optical fibers existing in the backhaul are considered in the models and reused to decrease the upgrading cost and improve reliability. The presented models can deliver topologies for various requirements on cost and resilience. They can also be used to develop topology planning and optimization tools.

Evolution of ethernet standards in the IEEE 802.3 working group

Abstract: Ethernet is constantly evolving, adapting to the needs of the networking world, addressing the requirements of both operators and end users, while making sure that the resulting technology is cost-efficient, reliable, and operates in a plug-and-play manner. The IEEE 802.3 Working Group has been working for the last 30+ years, pushing the boundaries on the speed and capacity of wireline Ethernet links, migrating from shared medium CSMA/CD systems to switched point-to-point Ethernet and then introducing multilane technology and point-to-point emulation over shared media of passive optical networks. In this article, we look at the latest projects adding new features and capabilities to the family of wired Ethernet standards, enabling the exponential growth of the Ethernet ecosystem, driven by technical maturity, cost effectiveness, and broad market support.

Benefits and requirements of flexible-grid ROADMs and networks [invited]

Abstract: Due to claims of enhanced spectral efficiency and the ability to accommodate future modulation formats, flexible-grid networks in which the center wavelength and passband width of the optical channels can be set on the fly have attracted wide attention. A flexible-grid reconfigurable optical add/drop multiplexer (ROADM) requires more than a flexible-grid wavelength-selective switch, and a flexible-grid network requires far more than flexible-grid ROADMs. We discuss the technologies required to enable flexible-grid networks. We examine the potential benefits of using flexible-grid ROADMs and compare this approach with alternative strategies.

SDN and OpenFlow for converged access/aggregation networks

Abstract: This paper discusses necessary steps for the migration from today's residential network model to a converged access/aggregation platform based on software defined networks (SDN).

Energy-efficient optical access networks: issues and technologies

Abstract: This article discusses and clarifies the issues and technologies for the next-generation energy efficient optical access network from the viewpoints of its mid-term upgrade and long-term evolution. For reducing the total power consumption in the mid-term upgrade to 10-gigabit access, it is necessary to optimize the network configuration as well as the usage of various technologies while avoiding any service degradation in the next-generation broadband services. In the long-term evolution, wavelength routing will play a key role by drastically decreasing the total power consumption of the access network.

Software-defined optical access networks for multiple broadband access solutions

Abstract: The principles of software-defined networking as applied to multi-service broadband optical access systems are discussed, with an emphasis on centralized software-reconfigurable resource management, digital signal processing (DSP)-enhanced transceivers and multi-service support via software-reconfigurable network “apps”.