@techreport{TR-IC-13-25,
   number = {IC-13-25},
   author = {Rafael A. Scaraficci and Nelson L. S. da Fonseca},
   title  =  {{Alternative  Routing and Zone-Based Spectrum Assignment
                   Algorithm for Flexgrid Optical Networks}},
   month = {October},
   year = {2013},
   institution = {Institute of Computing, University of Campinas},
   note = {In English, 13 pages.
    \par\selectlanguage{english}\textbf{Abstract}
       In  optical  flexgrid  networks,  the  optical  spectrum can be
       allocated  at a much finer granularity that it can be allocated
       in  fixed-grid WDM networks, and connections can use a variable
       number  of  slots.  However, the dynamic establishment and tear
       down of lightpaths demanding variable spectrum widths yields to
       the  fragmentation of the spectrum with increase in blocking of
       connections;   mainly   connections  demanding  large  spectrum 
       widths.  This papers proposes a novel algorithm that introduces
       a  zone-based  assignment  policy  together with an alternative
       path routing mechanism based on the maximum capacity available.
       Results  derived  via simulation using different topologies and
       considering  connections requests from 40Gbps to 1000Gbps, show
       that   the   proposed   algorithm   leads   to  blocking  ratio 
       consistently  lower than those given by traditional approaches.
       Furthermore,  it  reduces  the  blocking  ratio  of  high rates
       connections, in some cases, in more than six times.
  }
}