3,847 research outputs found
Access and metro network convergence for flexible end-to-end network design
This paper reports on the architectural, protocol, physical layer, and integrated testbed demonstrations carried out by the DISCUS FP7 consortium in the area of access - metro network convergence. Our architecture modeling results show the vast potential for cost and power savings that node consolidation can bring. The architecture, however, also recognizes the limits of long-reach transmission for low-latency 5G services and proposes ways to address such shortcomings in future projects. The testbed results, which have been conducted end-to-end, across access - metro and core, and have targeted all the layers of the network from the application down to the physical layer, show the practical feasibility of the concepts proposed in the project
Virtual topology design and flow routing in optical networks under multi-hour traffic demand
This paper addresses the problem of finding a static
virtual topology design and flow routing in transparent optical
WDM networks under a time-varying (multi-hour) traffic
demand. Four variants of the problem are considered, using
fixed or dynamically adaptable (i.e., variable) flow routing,
which can be splittable or unsplittable. Our main objective is
to minimize the number of transceivers needed which make up
for the main network cost. We formulate the problem variants
as exact ILPs (Integer Linear Programs) and MILPs (Mixed
ILPs). For larger problem instances, we also propose a family
of heuristics based on the concept of domination between
traffic matrices. This concept provides the theoretical
foundations for a set of techniques proposed to reduce the
problem complexity. We present a lower bound to the network
cost for the case in which the virtual topology could be
dynamically reconfigured along time. This allows us to assess
the limit on the maximum possible benefit that could be
achieved by using optical reconfigurable equipment.
Extensive tests have been conducted, using both synthetically
generated and real-traced traffic demands. In the cases
studied, results show that combining variable routing with splittable flows obtains a significant, although moderate, cost
reduction. The maximum cost reduction achievable with
reconfigurable virtual topologies was shown to be negligible
compared to the static case in medium and high loads.The work described in this paper was
carried out with the support of the BONE project (“Building the Future Optical Network in Europe”); a Network of Excellence funded by the European Commission through the
7th ICT-Framework Program. This research has been partially supported by the projects from the Spanish Ministry Of Education TEC2007-67966-01/TCM CON-PARTE-1, and
TEC2008-02552-E, and it is also developed in the framework of the projects from Fundación Seneca (Regional Agency of Science and Technology of Region of Murcia ) 00002/CS/08
(FORMA) and "Programa de Ayudas a Grupos de Excelencia de la Región. de Murcia”, F. Séneca (Plan Regional de Ciencia y Tecnología 2007/2010)."
Impact of Amplification and Regeneration Schemes on the Blocking Performance and Energy Consumption of Wide-Area Elastic Optical Networks
This paper studies the physical layer’s impact on the blocking probability and energy consumption of wide-area dynamic elastic optical networks (EONs). For this purpose, we consider five network configurations, each named with a network configuration identifier (NCI) from 1 to 5, for which the Routing, Modulation Level, and Spectrum Assignment (RMLSA) problem is solved. NCI 1–4 are transparent configurations based on all-EDFA, hybrid Raman/EDFA amplifiers (with different Raman gain ratio ΓR ), all-DFRA, and alternating span configuration (EDFA and DFRA). NCI 5 is a translucent configuration based on all-EDFA and 3R regenerators. We model the physical layer for every network configuration to determine the maximum achievable reach of optical signals. Employing simulation, we calculate the blocking probability and the energy consumption of the different network configurations. In terms of blocking, our results show that NCI 2 and 3 offer the lowest blocking probability, with at least 1 and 3 orders of magnitude of difference with respect to NCI 1 and 5 at high and low traffic loads, respectively. In terms of energy consumption, the best performing alternatives are the ones with the worst blocking (NCI 1), while NCI 3 exhibits the highest energy consumption with NCI 2ΓR=0.75 following closely. This situation highlights a clear trade-off between blocking performance and energy cost that must be considered when designing a dynamic EON. Thus, we identify NCI 2 using ΓR=0.25 as a promising alternative to reduce the blocking probability significantly in wide-area dynamic EONs without a prohibitive increase in energy consumption
Benchmarking and viability assessment of optical packet switching for metro networks
Optical packet switching (OPS) has been proposed as a strong candidate for future metro networks. This paper assesses the viability of an OPS-based ring architecture as proposed within the research project DAVID (Data And Voice Integration on DWDM), funded by the European Commission through the Information Society Technologies (IST) framework. Its feasibility is discussed from a physical-layer point of view, and its limitations in size are explored. Through dimensioning studies, we show that the proposed OPS architecture is competitive with respect to alternative metropolitan area network (MAN) approaches, including synchronous digital hierarchy, resilient packet rings (RPR), and star-based Ethernet. Finally, the proposed OPS architectures are discussed from a logical performance point of view, and a high-quality scheduling algorithm to control the packet-switching operations in the rings is explained
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