Framework for waveband switching in multigranular optical networks: part I-multigranular cross-connect architectures

Optical networks using wavelength-division multiplexing (WDM) are the foremost solution to the ever-increasing traffic in the Internet backbone. Rapid advances in WDM technology will enable each fiber to carry hundreds or even a thousand wavelengths (using dense-WDM, or DWDM, and ultra-DWDM) of traffic. This, coupled with worldwide fiber deployment, will bring about a tremendous increase in the size of the optical cross-connects, i.e., the number of ports of the wavelength switching elements. Waveband switching (WBS), wherein wavelengths are grouped into bands and switched as a single entity, can reduce the cost and control complexity of switching nodes by minimizing the port count. This paper presents a detailed study on recent advances and open research issues in WBS networks. In this study, we investigate in detail the architecture for various WBS cross-connects and compare them in terms of the number of ports and complexity and also in terms of how flexible they are in adjusting to dynamic traffic. We outline various techniques for grouping wavelengths into bands for the purpose of WBS and show how traditional wavelength routing is different from waveband routing and why techniques developed for wavelength-routed networks (WRNs) cannot be simply applied to WBS networks. We also outline how traffic grooming of subwavelength traffic can be done in WBS networks. In part II of this study [Cao , submitted to J. Opt. Netw.], we study the effect of wavelength conversion on the performance of WBS networks with reconfigurable MG-OXCs. We present an algorithm for waveband grouping in wavelength-convertible networks and evaluate its performance. We also investigate issues related to survivability in WBS networks and show how waveband and wavelength conversion can be used to recover from failures in WBS networks

Multi-Granular Optical Cross-Connect: Design, Analysis, and Demonstration

A fundamental issue in all-optical switching is to offer efficient and cost-effective transport services for a wide range of bandwidth granularities. This paper presents multi-granular optical cross-connect (MG-OXC) architectures that combine slow (ms regime) and fast (ns regime) switch elements, in order to support optical circuit switching (OCS), optical burst switching (OBS), and even optical packet switching (OPS). The MG-OXC architectures are designed to provide a cost-effective approach, while offering the flexibility and reconfigurability to deal with dynamic requirements of different applications. All proposed MG-OXC designs are analyzed and compared in terms of dimensionality, flexibility/reconfigurability, and scalability. Furthermore, node level simulations are conducted to evaluate the performance of MG-OXCs under different traffic regimes. Finally, the feasibility of the proposed architectures is demonstrated on an application-aware, multi-bit-rate (10 and 40 Gbps), end-to-end OBS testbed

Resource Management in Survivable Multi-Granular Optical Networks

The last decade witnessed a wild growth of the Internet traffic, promoted by bandwidth-hungry applications such as Youtube, P2P, and VoIP. This explosive increase is expected to proceed with an annual rate of 34% in the near future, which leads to a huge challenge to the Internet infrastructure. One foremost solution to this problem is advancing the optical networking and switching, by which abundant bandwidth can be provided in an energy-efficient manner. For instance, with Wavelength Division Multiplexing (WDM) technology, each fiber can carry a mass of wavelengths with bandwidth up to 100 Gbits/s or higher. To keep up with the traffic explosion, however, simply scaling the number of fibers and/or wavelengths per fiber results in the scalability issue in WDM networks. One major motivation of this dissertation is to address this issue in WDM networks with the idea of waveband switching (WBS). This work includes the author\u27s study on multiple aspects of waveband switching: how to address dynamic user demand, how to accommodate static user demand, and how to achieve a survivable WBS network. When combined together, the proposed approaches form a framework that enables an efficient WBS-based Internet in the near future or the middle term. As a long-term solution for the Internet backbone, the Spectrum Sliced Elastic Optical Path (SLICE) Networks recently attract significant interests. SLICE aims to provide abundant bandwidth by managing the spectrum resources as orthogonal sub-carriers, a finer granular than wavelengths of WDM networks. Another important component of this dissertation is the author\u27s timely study on this new frontier: particulary, how to efficiency accommodate the user demand in SLICE networks. We refer to the overall study as the resource management in multi-granular optical networks. In WBS networks, the multi-granularity includes the fiber, waveband, and wavelength. While in SLICE networks, the traffic granularity refers to the fiber, and the variety of the demand size (in terms of number of sub-carriers)

Smart Algorithms for Hierarchical Clustering in Optical Network

Network design process is a very important in order to balance between the investment in the network and the supervises offered to the network user, taking into consideration, both minimizing the network investment cost, on the other hand, maximizing the quality of service offered to the customers as well.Partitioning the network to smaller sub-networks called clusters is required during the design process inorder to ease studying the whole network and achieve the design process as a trade-off between several atrtributes such as quality of service, reliability,cost, and management. Under CANON, a large scale optical network is partitioned into a number of geographically limited areas taking into account many different criteria like administrative domains, topological characteristics, traffic patterns, legacy infrastructure etc. An important consideration is that each of these clusters is comprised of a group of nodes in geographical proximity. The clusters can coincide with administrative domains but there could be many cases where two or more clusters belong to the same administrative domain. Therefore, in the most general case the partitioning into specific clusters can be either a off-line or a on-line process. In this work only the off-line case is considered. In this Study, we look at the problem of designing efficient 2- level Hierarchical Optical Networks (HON), in the context of network costs optimization. 2-level HON paradigm only have local rings to connect disjoint sets of nodes and a global sub mesh to interconnect all the local rings. We present an Hierarchical algorithm that is based on two phases. We present results for scenarios containing a set of real optical topologies

Optical architectures for high performance switching and routing

This thesis investigates optical interconnection networks for high performance switching and routing. Two main topics are studied. The first topic regards the use of silicon microring resonators for short reach optical interconnects. Photonic technologies can help to overcome the intrinsic limitations of electronics when used in interconnects, short-distance transmissions and switching operations. This thesis considers the peculiarasymmetric losses of microring resonators since they pose unprecedented challenges for the design of the architecture and for the routing algorithms. It presents new interconnection architectures, proposes modifications on classical routing algorithms and achieves a better performance in terms of fabric complexity and scalability with respect to the state of the art. Subsequently, this thesis considers wavelength dimension capabilities of microring resonators in which wavelength reuse (i.e. crosstalk accumulation) presents impairments on the system performance. To this aim, it presents different crosstalk reduction techniques, a feasibility analysis for the design of microring resonators and a novel wavelength-agile routing matrix. The second topic regards flexible resource allocation with adaptable infrastructure for elastic optical networks. In particular, it focus on Architecture on Demand (AoD), whereby optical node architectures can be reconfigured on the fly according to traffic requirements. This thesis includes results on the first flexible-grid optical spectrum networking field trial, carried out in a collaboration with University of Essex. Finally, it addresses several challenges that present the novel concept AoD by means of modeling and simulation. This thesis proposes an algorithm to perform automatic architecture synthesis, reports AoD scalability and power consumption results working under the proposed synthesis algorithm. Such results validate AoD as a flexible node concept that provides power efficiency and high switching capacity

Resilient optical multicasting utilizing cycles in WDM optical networks

High capacity telecommunications of today is possible only because of the presence of optical networks. At the heart of an optical network is an optical fiber whose data carrying capabilities are unparalleled. Multicasting is a form of communication in wavelength division multiplexed (WDM) networks that involves one source and multiple destinations. Light trees, which employ light splitting at various nodes, are used to deliver data to multiple destinations. A fiber cut has been estimated to occur, on an average, once every four days by TEN, a pan-European carrier network. This thesis presents algorithms to make multicast sessions survivable against component failures. We consider multiple link failures and node failures in this work. The two algorithms presented in this thesis use a hybrid approach which is a combination of proactive and reactive approaches to recover from failures. We introduce the novel concept of minimal-hop cycles to tolerate simultaneous multiple link failures in a multicast session. While the first algorithm deals only with multiple link failures, the second algorithm considers the case of node failure and a link failure. Two different versions of the first algorithm have been implemented to thoroughly understand its behavior. Both algorithms were studied through simulators on two different networks, the USA Longhaul network and the NSF network. The input multicast sessions to all our algorithms were generated from power efficient multicast algorithms that make sure the power in the receiving nodes are at acceptable levels. The parameters used to evaluate the performance of our algorithms include computation times, network usage and power efficiency. Two new parameters, namely, recovery times and recovery success probability, have been introduced in this work. To our knowledge, this work is the first to introduce the concept of minimal hop cycles to recover from simultaneous multiple link failures in a multicast session in optical networks

Framework For Performance Analysis of Optical Circuit Switched Network Planning Algorithms

Projecte final de carrera realitzat en col.laboració amb Ecole Polytechnique Fédérale de Lausann

On wavelength-routed networks with reversible wavelength channels

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