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    Item type:Publication,
    Large L-shape Fit Spectrum Allocation for Elastic Optical Network with Spectrum Slicing
    (2021-01-13)
    Akaki, Kaito
    ;
    Pavarangkoon, Praphan
    ;
    Kitsuwan, Nattapong
    A slicing and stitching technology has been invented to relax the consecutive constraint of spectrum slot allocation in elastic optical network (EON). This technology splits a spectrum band into several signal bands, called optical components, by making a copy of the original spectrum band and filtering out an unwanted signal on each spectrum band. The remaining optical components are injected into a transmission channel. At the destination, the optical components are recovered by using phase preserving wavelength conversion. Therefore, a request is able to allocate to dis-consecutive groups of slots. A conventional spectrum allocation scheme with this technology adopts slicing devices, called spectrum slicers, at only a source node. There is a problem of allocation patterns due to lack of flexibility since slicing at intermediate nodes is not considered. In this paper, we propose a spectrum allocation scheme considering slicers at both source node and intermediate nodes. Performance of the proposed scheme is evaluated by a computer simulation. The results show that the proposed scheme with 20 slicers reduces 45% of request blocking probability compared to the conventional scheme in COST239 topology when the traffic is 300 Erlang.
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    Item type:Publication,
    Elastic optical network for fragmented bandwidth allocation with limited slicers
    (2021-01-01)
    Akaki, Kaito
    ;
    Pavarangkoon, Praphan
    ;
    Kitsuwan, Nattapong
    A fragmentation problem increases bandwidth blocking in an elastic optical network (EON). A technique to reduce bandwidth fragmentation is important. The routing and spectrum allocation (RSA) approach is one of the techniques to reduce bandwidth fragmentation. A slicing-and-stitching technology is adopted in EON to relax a consecutive slot constraint for the spectrum allocation process. A slicer is used to split a signal of a spectrum band into several spectrum components, as a slicing process. The split spectrum components are transmitted to the destination before recovering the original signal at the destination, as a stitching process. An RSA algorithm for EON with this technology is applied. As a result, the request blocking is reduced. Slicers are applied to all nodes in the network. The implementation cost is high. Reducing the number of slicers in the network degrades the performance in terms of bandwidth blocking. This paper investigates bandwidth blocking when the number of slicers is limited. Some nodes in the network are selected to place slicers. A betweenness centrality (BC) value is used to select the nodes to place the slicers. The result from a simulation shows that placing a small number of slicers per node for a large number of nodes has better performance than placing a large number of slicers per node for a small number of nodes.