Optical Network Infrastructure Research Articles

Advanced radio over fiber network technologies

The evolution of wireless communication networks supporting emerging broadband services and applications offers new opportunities for realizing integrated optical and wireless network infrastructures. We report on some of our recent activities investigating advanced technologies for next generation converged optical wireless networks. Developments in Active Antenna Systems, mobile fronthaul architectures, and 60 GHz fiber distributed wireless networks are described. We also discuss the potential for analog radio over fiber distribution links as a viable solution for meeting the capacity requirements of new network architectures.

Role of Optical Network Virtualization in Cloud Computing [Invited

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.

Decomposed Radio Access Network Over Deployed Passive Optical Networks Using Coherent Optical OFDM Transceivers

In this paper, it is proposed to take advantage of the deployed passive optical network (PON) infrastructure by overlaying a decomposed radio access network (RAN) using a very dense WDM. Coherent optical orthogonal frequency-division multiplexing technology is investigated for achieving the desired narrow channel spacings while minimizing the impact on the performance of legacy equipment. A practical implementation is evaluated using simulations. Within the analyzed configurations, a trade-off is found between time-division multiplexed (TDM)-PON and RAN performance. The optimum balance is found for additional losses in the TDM-PON path of less than 1 dB, ensuring simultaneous service to a maximum of 145 metro cells together with the PON customers and within a reach of 24 km.

Secure Optical Networks Based on Quantum Key Distribution and Weakly Trusted Repeaters

In this paper we explore how recent technologies can improve the security of optical networks. In particular, we study how to use quantum key distribution (QKD) in common optical network infrastructures and propose a method to overcome its distance limitations. QKD is the first technology offering information theoretic secret-key distribution that relies only on the fundamental principles of quantum physics. Point-to-point QKD devices have reached a mature industrial state; however, these devices are severely limited in distance, since signals at the quantum level (e.g. single photons) are highly affected by the losses in the communication channel and intermediate devices. To overcome this limitation, intermediate nodes (i.e. repeaters) are used. Both, quantum-regime and trusted, classical, repeaters have been proposed in the QKD literature, but only the latter can be implemented in practice. As a novelty, we propose here a new QKD network model based on the use of not fully trusted intermediate nodes, referred as weakly trusted repeaters. This approach forces the attacker to simultaneously break several paths to get access to the exchanged key, thus improving significantly the security of the network. We formalize the model using network codes and provide real scenarios that allow users to exchange secure keys over metropolitan optical networks using only passive components. Moreover, the theoretical framework allows to extend these scenarios not only to accommodate more complex trust constraints, but also to consider robustness and resiliency constraints on the network.

Distribution of Broadband Services Over 1-mm Core Diameter Plastic Optical Fiber for Point-to-Multipoint In-Home Networks

This paper presents a point-to-multipoint (P2MP) in-home optical network infrastructure based on 1-mm core diameter plastic optical fiber (POF). By employing passive POF splitters, converged broadband wired and wireless service transmission over a P2MP POF infrastructure is demonstrated. A gross 2.2 Gb/s fractional discrete multitone (DMT) and a 528-MHz ultra wideband (UWB) wireless signal distribution simultaneously to four end-users are successfully achieved with BER <; 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> and EVM <; 15.5% , respectively. Up to 50 m transmission distance is achieved using off-the-shelf optical components. This feasibility study on all-optical P2MP infrastructures presents a promising low-cost solution for high-speed in-home broadband communication.

Increasing energy efficiency in OCDMA network via distributed power control

In this work, we investigate the utilization of transmission power control as mechanism to increase the energy efficiency in optical code division multiplexing access (OCDMA) networks. We have modeled the energy efficiency considering the optical fiber transmission and network infrastructure as encoders, decoders and star coupler. In the analyzed scenario, this model confirms that the energy consumption of the network infrastructure is larger than the energy consumption of the transmission infrastructure; On the other hand, we have proposed a scheme to define the energy efficiency according to the BER level accomplished with the quality of service (QoS) requirements. The main results showed that it is possible to save 70% of the transmitted energy per bit with the penalty of one order of magnitude of BER.

Dynamic Provisioning of Self-Organized Consumer Grid Services Over Integrated OBS/WSON Networks

Significant technical progress in the computer science and networking, as well as the rapid increase in users' requirements for computational resources and diverse services, is leading to the gradual opening of Grid computing, which is mainly a scientific- or business-oriented application, to the consumer market. Such a scenario, often referred to as the consumer Grid, is a major challenge because of the potentially large number of dynamic resources and users (perhaps millions), high frequency of job requests, and considerable heterogeneity in resource types in the consumer market. These features will lead to several potential issues when consumer Grid services are deployed with existing techniques. In this paper, we analyze the limitations of current network infrastructures, resource discovery and management schemes and end-to-end transmission control protocols (TCP) that prevent the wide deployment of consumer Grid services. Then, in order to address these issues, we propose an integrated optical burst switching (OBS)/wavelength switched optical network (WSON) infrastructure assisted by a self-organized resource discovery and management scheme to support the consumer Grid. In addition, we review several alternative TCP protocols and compare their performance in term of throughput and fairness to select the most suitable TCP protocol for end-to-end Grid data transmission. To the best of our knowledge, this is the first time that these solutions have been proposed and investigated for the consumer Grid, and more importantly, all the proposed methodologies are demonstrated and evaluated on an actual OBS/WSON testbed with both control and data planes, allowing the verification of their feasibility and effectiveness, and obtaining valuable insights for deploying the proposed solutions into real consumer Grid networks.

Evolutionary optimization for energy efficient service provisioning in IT and optical network infrastructures

This paper focuses on energy efficient service provisioning in integrated IT and optical network infrastructures. A novel evolutionary distributed approach is proposed and compared with ILP based centralized approaches and modeling results quantify similar performance.

Mixed Placement of 1R/2R/3R Regenerators in Translucent Optical Networks to Achieve Green and Cost-Effective Design

We develop a theoretical model to estimate the BER evolutions in optical translucent networks in a more accurate way. The model calculates the BER increment at each regeneration site with considerations of reshaping nonlinearity and jitter effect for 40 Gb/s signals. Based on the model, we propose a novel translucent optical network infrastructure that includes all-optical 2R regenerators and uses mixed operation of 1R/2R/3R regenerators for cost and power consumption savings. Simulation results show that our proposed infrastructure reduces the number of O/E/O 3R regenerators to less than 50% and achieves effective power saving.

Architectures, protocols and design for highly dynamic optical networks

In order for dynamic optical networks to be commercially viable, it will be essential to have signaling protocols that can establish connections quickly and minimize the use of transponders for wavelength conversion and regeneration. Rough estimates indicate that in dynamic optical networks, transponders will comprise a significant component (e.g., 60%–70%) of the cost of the optical networking infrastructure. A key performance metric in dynamic networks is the connection blocking probability, and therefore a dynamic optical network infrastructure must be designed to meet stringent blocking requirements (e.g., <10−3 blocking probability). A key element in achieving that blocking objective is the ability to design the network to support shared transponder pools at selected network nodes, and have the capability to efficiently size those transponder pools to meet the required blocking probabilities. This paper addresses how to size shared transponder pools once the nodes that support those pools have been determined. The methodology can efficiently design for very small transponder-related blocking probability (e.g., <10−4) by using simple, straightforward simulation and analysis techniques. We also describe a 3-Way-Handshake (3WHS) signaling protocol that can quickly set up connections (e.g., in <100 ms) and identify available resources (available wavelengths, transponders) so the connection setup process minimizes the use of transponders.

High-performance network virtualisation for multilayer GMPLS networks

The recent trends in emerging network applications require more flexible network infrastructures. For this purpose, we consider the architecture and enabling technologies of high-performance network virtualisation using multilayer GMPLS networking technologies. The network virtualisation enables virtual network to utilise high-capacity bandwidth of optical network infrastructures without the provision of physical infrastructures. Furthermore, to improve robustness against network environmental changes such as failures and sudden traffic demand fluctuations, the network infrastructure provides virtual networks resource optimisation and on-demand resource distribution functions. One possible problem regarding virtualisation technologies lies in resource contention among multiple virtual networks sharing limited resources on the infrastructure. We thus propose a resource management model for efficient contention resolutions. We also present the design of a network virtualisation platform and the specification of interfaces to virtual network agents. We also developed prototype systems based on our system design and demonstrated the proposed high-performance lower-layer network virtualisation technologies in conjunction with commercially available routers and OXCs that support GMPLS protocols in our experimental network.

Enabling multi-user interaction in large high-resolution distributed environments

As the amount and the resolution of collected scientific data increase, scientists are realizing the potential benefits that large high-resolution displays can have in assimilating this incoming data. Often this data has to be processed on powerful remote computing and storage resources, converted to high-resolution digital media and yet visualized on a local tiled-display. This is the basic premise behind the OptIPuter model. While the streaming middleware to enable this kind of work exists and the optical networking infrastructure is becoming more widely available, enabling multi-user interaction in such environments is still a challenge. In this paper, we present an interaction system we developed to support collaborative work on large high-resolution displays using multiple interaction devices and scalable, distributed user interface widgets. This system allows multiple users to simultaneously interact with local or remote data, media and applications, through a variety of physical interaction devices on large high-resolution displays. Finally, we present our experiences with using the system over the past two years. Most importantly, having an actual working system based on the OptIPuter model allows us to focus our research efforts to better understand how to make such high-resolution environments more user-friendly and usable in true real-world collaborative scenarios as opposed to constrained laboratory settings.

GMPLS-based Multidomain Restoration: Analysis, Strategies, Policies and Experimental Assessment

A connection spanning, for example, several countries crosses multiple optical backbone networks, each one controlled by different administrators or operators. In this context, the interworking of these networks is thus necessary to set up end-to-end optical connections. A key issue when delivering such optical services is the use of efficient and fast restoration strategies to recover a connection disruption. To this end, there are several issues and policies that a network operator should address, such as interdomain failure information exchange and the point of repair (PoR) placement problem. Upon a failure’s occurrence, exchanging interdomain failure information results is essential to attain both an efficient use of the network resources (i.e., wavelength channels) and a fast restoration time. In this regard, within the GMPLS (Generalized Multi-Protocol Label Switching) framework, interdomain information exchange remains unstandardized. Three network operator policies are proposed to yield different restoration mechanisms according to different interdomain failure exchanges. Additionally, three PoR strategies are pointed out and are qualitatively compared. Finally, selected policies and restoration strategies are experimentally validated and compared in terms of the restoration time. Experiments have been carried out over a multidomain optical network infrastructure connecting the GMPLS-based control planes of the UPC CARISMA and the CTTC ADRENALINE test beds.

Realizing the optical transport networking vision in the 100 Gb/s era

After a half-decade hiatus, stimulated by dramatic service-driven increases in backbone network bandwidth requirements, industry focus has once again turned to realizing a vision of optical transport networking (OTN). In the timeframe since the first OTN standards were stabilized, technology has continued to evolve, and additional new service requirements have materialized. The ability to provide optimized support for gigabit Ethernet services, ranging from 1Gb/s to 100 Gb/s, has become a high priority. This paper examines how evolving OTN standards provide a multi-service capable backbone infrastructure supporting lambda and sub-lambda services with guaranteed quality, the role of optical control plane technology in realizing dynamically configurable OTN and Internet Protocol (IP) over optical transport networking solutions, and emerging technology enablers. The paper concludes by providing a vision of optical transport network infrastructure evolution in the 100 Gb/s era. é 2010 Alcatel-Lucent.

On-Demand End-to-End Optical Network Construction for Grid Applications with Adaptive and Distributed Control over Multi-Domain WSONs

In this paper, we address the on-demand end-to-end optical network construction problem for grid applications in new generation large-scale multi-domain wavelength switched optical networks (WSON). According to users' requests for high-performance distributed computing, groups of dedicated end-to-end lightpaths among geographically distributed grid resources can be established dynamically forming multiple-lightpath optical networks for grid applications, namely, optical grid network (OGN). To facilitate the automated OGN construction, we introduce an optical grid network infrastructure providing an integrated and self-contained OGN service to grid users with totally distributed control. In this infrastructure, for easy construction, especially in a large-scale multi-domain WSON environment, we propose an overlay approach to construct OGNs in a peer-to-peer fashion, which conceals the communication architecture of the underlying heterogeneous optical networks. In particular, we propose an adaptive construction mechanism that can develop the OGN flexibly by adapting to the dynamically changed optical network circumstance. To enable users to take the advantage of the end-to-end lightpaths of WSON directly, a wavelength-oriented end-host configuration scheme is proposed. Experimental results on a developed prototype and an optical-fibre test-bed network successfully validate the proposal.

Maintenance and Operation Technologies for Optical Access Fiber Network Infrastructure

The optical access fiber network is spreading rapidly as a result of the progress made on optical communication technologies and the availability of a wide range of broadband Internet content. If the optical access network is not properly maintained, the service quality will decrease. This paper describes some effective technologies that have been researched and developed to maintain a high quality of service, and to achieve efficient maintenance and operation.

A Hybrid TDM/WDM-Pon System with FWM-Generated Source of Multiwavelength Optical Signals

A new approach to FTTx solutions is proposed, in the framework of which a hybrid TDM/WDM system using cascaded FWM-generated optical signals is evaluated by calculating the BER parameter and the optical power budget. Computer simulation is employed as the main method of calculations, with the results presented both in numerical and graphical forms. The results show that the use of a forward error correction allows the power margin of 4 dB to be achieved for the system to work reliably. The system can provide the total number of users up to 128 (8γx16 TDM users) with a bandwidth of multiple hundreds of Mbit/s p.u. by means of the existing passive optical networking infrastructure, with only minor improvements needed.

Virtualizing and Scheduling Optical Network Infrastructure for Emerging IT Services [Invited

Emerging IT service providers that aim at delivering supercomputing power available to the masses over the Internet rely on high-performance IT resources interconnected with ultra-high-performance optical networks. To adjust the provisioning of the resources to end-user demand variations, new infrastructure capabilities have to be supported. These capabilities have to take into account the business requirements of telecom networks. This paper proposes a service framework to offer Internet service providers dynamic access to extensible virtual private execution infrastructures, through on-demand and in-advance bandwidth and resource reservation services. This virtual infrastructure service concept is being studied in the CARRIOCAS project and implemented thanks to the scheduling, reconfiguration, and virtualization (SRV) component. This entity handles the service requests, aggregates them, and triggers the provisioning of different types of resources accordingly. We propose to adapt to envisioned heterogeneous needs by multiplexing rigid and flexible requests as well as coarse or fine demands. The goal is to optimize both resource provisioning and utility functions. Considering the options of advanced network bandwidth reservations and allocations, the optimization problem is formulated. The impacts of the malleability factor are studied by simulation to assess the gain.

Fair Resource Distribution Within the Flexible WDMA/TDMA Optical Access Network Based on GPON Infrastructure

In this paper a proposition for a flexible optical access network is presented. The general idea of a physical layer over an existing gigabit passive optical network (GPON) infrastructure is described, and three possible realizations are reported through laboratory experiments and computer simulations. Two algorithms for efficient bandwidth allocation in the time and wavelength domains have been designed, and the results of their application in one realistic scenario are reported. We found that the combined flexibility in the time and wavelength domains may handle burst arrivals in a cost-effective way and may be considered as a viable solution for upgrading optical access networks in the future.

Guest Editorial on Converged Optical Network Infrastructures in Support of Future Internet and Grid Services Special Issue

The four invited papers and 18 contributed papers in this special issue focus on the topic of converged optical network infrastructures in support of future Internet and grid services.