Papers by Alexandros Stavdas
2006 International Conference on Photonics in Switching, 2006
In this work, a migration scenario of a family of 2.
2014 European Conference on Networks and Communications (EuCNC), 2014
The ontology of communications is rapidly changing, shifting interest to machine-to-machine (M2M)... more The ontology of communications is rapidly changing, shifting interest to machine-to-machine (M2M) interactions and the internet of Things (IoT). These are becoming vital for sustainability of social life and the revitalization of the economy providing the infrastructure to new production forms like distributed manufacturing, cloud robotics while becoming important to grid-based energy systems. Adding to them the voracious needs for data of the traditional broadband users, residential or business, together with the back/front hauling requirements of mobile operators, one is expecting a significant strain in the access. A multitude of heterogeneous access networks are emerging and the integration of them in a single platform ensuring seamless data-exchange with Data-Centres is of major importance. In this paper we describe HYDRA (HYbriD long-Reach fiber Access network), a novel network architecture that overcomes the limitations of both long-reach PONs as well as mobile backhauling schemes, leading to significantly improved cost and power consumption figures. The key concept is the introduction of an Active Remote Node (ARN) that interfaces to end-users by means of the lowest cost/power consumption technology (short-range xPON, wireless, etc.) whilst 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, network convergence and Access-Core integration. The proposed architecture can enhance performance while supporting network virtualization and efficient resource orchestration based on Software Defined Networking (SDN) principles and open access networking models.
New Trends in Optical Network Design and Modeling, 2001
Advanced Photonics & Renewable Energy, 2010
The SMF bandwidth covers 1260-1625 nm offering the potential to create massive channel WDM-PONs. ... more The SMF bandwidth covers 1260-1625 nm offering the potential to create massive channel WDM-PONs. These PONs will play a key role in creating a flat Access network that allowing for a seamless integration with Core.
36th European Conference and Exhibition on Optical Communication, 2010
ABSTRACT
2006 European Conference on Optical Communications, 2006
We present three cross-layer routing algorithms incorporating physical layer input with different... more We present three cross-layer routing algorithms incorporating physical layer input with different performance-complexity tradeoffs. An example of their performance is given in a European scale network.
36th European Conference and Exhibition on Optical Communication, 2010
The benefit of node clustering in optical networks regarding routing with PLI awareness is invest... more The benefit of node clustering in optical networks regarding routing with PLI awareness is investigated under the CANON network architecture where regenerators are conveniently placed and routing is confined among a small subset of nodes.
This paper proposes HYbriD long-Reach fiber Access network (HYDRA), a novel network architecture ... more This paper proposes HYbriD long-Reach fiber Access network (HYDRA), a novel network architecture that overcomes many limitations of the current WDM/TDM PON approaches leading to significantly improved cost and power consumption figures.
Conference onOptical Network Design and Modeling, 2005., 2005
The e-Photon/ONe Network of Excellence (NoE) brings together a significant slection of the Europe... more The e-Photon/ONe Network of Excellence (NoE) brings together a significant slection of the European research groups that are active on photonic networking research topics. In this framework optical switching is seen as an important research topic and new approaches and concepts are emerging. In this work two such concepts are illustrated. The first is viewing a transparent optical network as a single entity, where transmission and switching are not treated as separate blocks consisting of non-interacting entities: optical switching not only routes wavelengths from incoming fibers to outgoing fibers, but also ensures robust transmission. The second is a proposed variation to an optical packet crossconnect that alleviates technological constraints of tunable wavelength converters, and expands in a new direction legacy design rules of multi-stage crossconnect switches.
2013 15th International Conference on Transparent Optical Networks (ICTON), 2013
In this paper, we evaluate the performance gains of a novel hybrid 2-stage TDM/WDM PON access net... more In this paper, we evaluate the performance gains of a novel hybrid 2-stage TDM/WDM PON access network over state-of-the-art Long-Reach WDM PONs. The proposed network architecture exploits very low cost enduser ONUs and achieves energy efficiency, reduced complexity and high-level scalability. The scheme allows a group of users to share an ultra-wide band long reach WDM-PON, in a fiber to the cabinet configuration, leading to core node consolidation and access-core integration. We quantify the benefits evaluating its application in large metropolitan area configurations using network planning techniques to reduce the number of nodes that are required to serve the expected capacity demand.
2012 16th International Conference on Optical Network Design and Modelling (ONDM), 2012
In this work we benchmark through appropriate performance metrics the legacy Optical Circuit Swit... more In this work we benchmark through appropriate performance metrics the legacy Optical Circuit Switching (OCS) mode in an optical network of nodes following a mesh topology interconnection vs. a clustered optical network architecture (CANON). The results demonstrate that the static reservation of WDM channels, as used in IP/WDM schemes, is severely limiting scalability, since it cannot efficiently adapt to the dynamic traffic fluctuations that are frequently observed in today's networks, while the hierarchical clustered architecture with dynamic reservations can exploit statistical multiplexing efficient grooming traffic at appropriate granularity levels leading to improved performance and resource utilization. We quantify through computer simulation the performance gains and the smoothing of traffic profile achieved when implementing the CANON architecture as an upgrade of existing infrastructure by using the reference network of a European operator. The effect of traffic grooming, when employing CANON and its impact on performance and cost are evaluated using a national backbone network as a case study.
39th European Conference and Exhibition on Optical Communication (ECOC 2013), 2013
We propose a novel optical cloud architecture where IT and Telecom resources are used interchange... more We propose a novel optical cloud architecture where IT and Telecom resources are used interchangeably as common infrastructure. Key assets are the MAC controlled passive networks for distributed multiplexing and grooming and a node architecture integrating transmission and switching.
Journal of Optical Networking, 2004
A system of slotted interconnected rings employing a combination of wavelength-division multiple ... more A system of slotted interconnected rings employing a combination of wavelength-division multiple access (WDMA) with time-division multiple access (TDMA) can serve a metropolitan area without electro-optical conversion and buffering of payload except at system entry points. The multiple rings overcome the power budget limitations of the single ring extending the reach of the system to even the largest metropolitan areas, the WDM dimension provides flexibility and ease of evolution, and the TDMA dimension offers the efficiency of multiplexing gain particularly under bursty traffic. The system control information is transferred on a dedicated wavelength and is processed in the electrical domain at the ring nodes and the hub, which interconnects the rings. The algorithms control the access to each ring and the scheduling of slots among the rings, based on explicit reservations, to adapt efficiently to the fluctuating offered load. We present the design and hardware implementation of the access control algorithms for such a system built in the framework of the Information Society Technologies (IST) project DAVID (data and voice over DWDM).
Workshop on High Performance Switching and Routing, 2003, HPSR., 2003
The deployment of WDM technology in metropolitan area networks has moved the bottleneck from capa... more The deployment of WDM technology in metropolitan area networks has moved the bottleneck from capacity to data processing at the network nodes. The data circulating in all wavelengths are converted from optical to electrical for being processed, thus increasing considerably the system's cost and complexity. Abolishing the SONET paradigm, new data control mechanisms are designed for interconnected WDM metro rings, alleviating the required processing and pushing it to the network edges. Moreover, based on these control mechanisms, the transport of network data in the optical domain is feasible, reducing the system buffering needs as well as the total number of transceivers in the network nodes. The proposed scheme has been implemented in hardware for a prototype that supports a total of 1.2Tbps metro traffic, and its design is described in the current paper.
IFIP Advances in Information and Communication Technology, 2003
Traffic segregation is essential in shared medium systems to allow best-effort traffic to coexist... more Traffic segregation is essential in shared medium systems to allow best-effort traffic to coexist with delay-sensitive traffic without the former disturbing the QoS of the latter. Rigid allocation per traffic class is very inefficient so a dynamic method that exploits the elastic behaviour of best-effort traffic due to its closed loop control is essential for high system utilisation. A novel MAC mechanism for slotted WDM rings based on class reservations is presented and evaluated in this paper. It allows the reservations to fluctuate in accordance with the demand for real-time traffic leaving the rest of the bandwidth for besteffort traffic. Thus the QoS-demanding traffic experiences no competition from best-effort traffic while the latter is inserted whenever spare bandwidth exists to increase system efficiency.
Solid-State Science and Technology Library, 2002
ABSTRACT The existence, formation and stability of solitons in a system of linearly coupled compl... more ABSTRACT The existence, formation and stability of solitons in a system of linearly coupled complex cubic Ginzburg-Landau (CGL) equations is studied in detail taking into account linear distributed gain, dispersive losses and Kerr nonlinearity in the doped component and linear losses in the passive one in a dual-core nonlinear fiber. Exact analytical chirped soliton solutions are derived and their propagation features and stability are investigated. Interaction of the soliton solutions and applications to TDM and WDM chirped soliton transmission are studied. The collision-induced delay of the interacting solitons in the WDM case is estimated as well. There is a strong evidence that, in both TDM and WDM cases, the chirped solitons are stabilized by the presence of the passive core. A possibility of generating stable chirped solitons out of unchirped ones is also demonstrated. The lumped version of this model could be the basis for a plausible optical transmission system with periodic amplification via a dual-core EDFA confined in the amplification hub.
2008 Third International Conference on Internet and Web Applications and Services, 2008
Telco -Web convergence will pave the way to unlock a new wave of innovation for future services a... more Telco -Web convergence will pave the way to unlock a new wave of innovation for future services and application scenarios: openness, broad federations of Players and do-it-yourself innovative services and knowledge management will allow people to be the true center of Information Society. To achieve this vision, this paper proposes a "service and knowledge ecosystem" based on a plurality of autonomic components, pervasively distributed over peer-to-peer (low-cost) resources, interacting with each other (even semantically) to compose and execute services and applications.
Optical Transmission Systems and Equipment for Networking V, 2006
In spite of its long term promise, all-optical switching is still plagued by high cost, low effic... more In spite of its long term promise, all-optical switching is still plagued by high cost, low efficiency when handling bursty data traffic, immature management and protection and poor output port contention resolution leading to heavy loss. Given the current situation, hybrid approaches that keep the best features of optics, reverting to the electrical plane when expedient, constitute sensible interim steps that can offer cost-effective solutions along the road to an eventual all-optical core. Two such approaches developed in the framework of the European IP project NOBEL are presented in this work. The first is a quite mature solution that extends present day concepts to achieve multiplexing gain while keeping all the management and restoration benefits of SDH. The other mimics early LANs in executing a distributed switching via its electrical control plane using two-way reservations, thus restricting its applicability to smaller domains. Combining the two leads to a system fulfilling most of today's requirements for Tb/s core networks.
Journal of Optical Communications, 2001
The probability density function of four-wave-mixing crosstalk in wavelength-division-multiplexin... more The probability density function of four-wave-mixing crosstalk in wavelength-division-multiplexing systems is derived analytically in a closed-form formula. For dispersion shifted fiber the plots were given for different number of channels, different channel indexes and different channel spacings. The comparison with Gaussian approximation is given, and the limits of its application are pointed out.
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Papers by Alexandros Stavdas