E. Limal

ETH Zurich, Zürich, Zurich, Switzerland

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Publications (9)4.14 Total impact

  • C. Fenger, E. Limal, U. Gliese
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    ABSTRACT: We present a statistical study of wavelength usage in relation to topology characteristics for optical WDM networks. New general correlations between topology parameters and wavelength usage are identified to simplify the network planning process
    Optical Fiber Communication Conference, 2000; 02/2000
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    ABSTRACT: We present a statistical study of wavelength usage in relation to topology characteristics for optical WDM networks with static traffic requirements, where the traffic is routed both with and without wavelength conversion. We identify new general correlations between parameters describing network topologies and wavelength usage. We find that the regularity of a network and the number of spanning trees in a network are accurate and reliable measures of the routing efficiency in terms of wavelengths used to accommodate the required traffic. An empirical formula is given for the average number of wavelengths required to accommodate the traffic as a function of the number spanning trees in the network. We observe that in most cases, the wavelength usage with and without wavelength converters are identical. Consequently, the correlations between network topology and traffic assignment efficiency are true for both types of networks.
    NETWORKING 2000, Broadband Communications, High Performance Networking, and Performance of Communication Networks, IFIP-TC6 / European Commission International Conference, Paris, France, May 14-19, 2000, Proceedings; 01/2000
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    ABSTRACT: this paper is to briefly review the current state of optical wavelength conversion technology with emphasis on all-optical wavelength converters. Although WDM networks have the attractive feature that di#erent signal formats can be transported in di#erent wavelength layers, our focus will be on binary signal formats that are by far dominant for telecommunication tra#c.
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    E. Limal, K.E. Stubkjaer
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    ABSTRACT: We present an algorithm for restoration of single link failure in wavelength routing multihop optical networks. The algorithm is based on an innovative study of networks using graph theory. It has the following original features: it (i) assigns working and spare channels simultaneously, (ii) prevents the search for unacceptable routing paths by pointing out channels required for restoration, (iii) offers a high utilization of the capacity resources and (iv) allows a trivial search for the restoration paths. The algorithm is for link restoration of networks without wavelength translation. Its low complexity is studied in detail and compared to the complexity of a classical path assignment algorithm. Finally, we explain how to use the algorithm to control the restoration path lengths
    Communications, 1999. ICC '99. 1999 IEEE International Conference on; 02/1999
  • E. Limal, K.E. Stubkjaer
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    ABSTRACT: We compare optical wavelength multiplexing and time multiplexing techniques for optical transport network by studying the space switch sizes of optical cross connects (OXCs) and their interfaces as a function of the fraction of add/drop traffic
    Optical Fiber Communication Conference, 1999, and the International Conference on Integrated Optics and Optical Fiber Communication. OFC/IOOC '99. Technical Digest; 02/1999
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    ABSTRACT: Four different topological approaches to designing a pan-European optical network are discussed. For such an ultra-high capacity large-scale network, it is necessary to overcome physical path length limitations and to limit optical cross-connect (OXC) complexity
    Optical Communication, 1998. 24th European Conference on; 10/1998
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    ABSTRACT: The European ACTS project optical pan-European network (OPEN) aims at assessing the feasibility of an optical pan-European overlay network, interconnecting major European cities by means of a mesh of high-capacity optical fiber links, cross-connected through transparent photonic nodes. Both the transmission links and the routing network elements rely on wavelength division multiplexing (WDM) all-optical technologies, such as wavelength translation. This paper presents results obtained in the following domains covered within the project: network topology considerations (optimization and dimensioning); network physical layer simulation; fabrications of packaged functional modules based on advanced optoelectronic devices; laboratory demonstrations of N×10 Gb/s transmission and routing; feasibility of an optical time division multiplexing/WDM (OTDM/WDM) interface; and the field implementation of a 4×4 multiwavelength crossconnect prototype, featuring all-optical space and wavelength routing. This implementation was realized in two cross-border field trials, one conducted between Norway and Denmark and the other between France and Belgium. The final results of the Norway to Denmark field trials are presented, featuring the successful cascade of three wavelength-translating optical crossconnects (OXCs), along with the transmission over 1000 km of a mix of standard/submarine cable links for four channels at 2.5 Gb/s
    IEEE Journal on Selected Areas in Communications 10/1998; DOI:10.1109/49.725192 · 4.14 Impact Factor
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    ABSTRACT: The construction of resilient wavelength-routed optical networks has attracted much interest. Many network topologies, path and wavelength assignment strategies have been proposed. The assessment of network strategies is very complex and comparison is difficult. Here, we take a novel analytical approach in estimating the maximum capacity utilization that is possible in wavelength-division multiplexing (WDM) networks that are resilient against single link failures. The results apply to general network topologies and can therefore be used to evaluate the performance of more specific wavelength and path assignment algorithms
    Optical Fiber Communication Conference and Exhibit, 1998. OFC '98., Technical Digest; 03/1998
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    ABSTRACT: This paper deals with optical transport network design using wavelength division multiplexing (WDM) facilities. It proposes a method for building networks from sub-network combinations. Two types of 4-node sub-networks and their properties are presented. For each sub-network, any fiber break can be recovered using re-routing paths. A European network set-up illustrates the method capabilities. The network has 19 nodes connected through 39 links distributed within 9 semi-mesh sub-networks. Comparison is made between local and non-local re-routing and between channel capacities of 2.5 and 10 Gb/s. The use of wavelength converters is also investigated. Advantages and drawbacks of different solutions are given with emphasis on fiber length and optical cross-connect size
    Communications, 1997. ICC 97 Montreal, 'Towards the Knowledge Millennium'. 1997 IEEE International Conference on; 07/1997