16 research outputs found
Resource reservation protocols for optical burst switched networks
Nesta disserta c~ao e feito um estudo em redes com comuta c~ao optica de agregados
de pacotes (redes OBS). Assim, este estudo apresenta e descreve os conceitos
mais importantes relacionados com as redes OBS.
Inicialmente e analisado o estado da arte, efectuando uma descri c~ao detalhada
da arquitectura de uma rede OBS.
Seguidamente analisam-se os protocolos de reserva unidireccional de recursos
(JIT, JIT+, JET, Jumpstart, Horizon and E-JIT). Para isso s~ao utilizadas redes
com topologias regulares (em anel e em malha) com um n umero vari avel de n os,
e tamb em irregulares (NSFNET e ARPANET). E tamb em apresentado um novo
protocolo de reserva unidireccional de recursos chamado E-JIT+.
Este novo protocolo baseia-se no protocolo j a existente JIT+ e tenta optimizar
o seu desempenho. Para melhor descrever o modo de opera c~ao deste
protocolo proposto e apresentada a especi ca c~ao formal do mesmo. Depois da
apresenta c~ao deste protocolo analisa-se o seu desempenho. Para isso s~ao utilizadas
as topologias de rede referidas anteriormente e tamb em um simulador de
redes OBS adaptado de forma a suportar o novo protocolo.
O simulador utilizado, de nome OBSSimulator, devolve os valores de probabilidade
de perda dos agregados de pacotes em cada salto (hop) na rede. Deste
modo, foram considerados v arios factores que podem in
uenciar o desempenho
dos protocolos de reserva unidireccional de recursos, tais como o n umero de n os
da topologia de rede utilizada, a quantidade de tr afego na rede, o ganho do
grau nodal, o tempo de processamento das mensagens de setup e o tempo de
con gura c~ao dos comutadores opticos. No m deste trabalho concluiu-se que
o protocolo proposto, E-JIT+, melhora o desempenho em rela c~ao aos outros
protocolos de reserva unidireccional de recursos estudados, nos casos estudados
Tuchola County Broadband Network (TCBN)
Abstract
In the paper the designing project (plan) of Tuchola City broadband IP optical network has been presented. The extended version of network plan constitute technical part of network Feasibility Study, that it is expected to be implemented in Tuchola and be financed from European Regional Development Funds. The network plan presented in the paper contains both topological structure of fiber optic network as well as the active equipment for the network. In the project described in the paper it has been suggested to use Modular Cable System - MCS for passive infrastructure and Metro Ethernet technology for active equipment. The presented solution provides low cost of construction (CAPEX), ease of implementation of the network and low operating cost (OPEX). Moreover the parameters of installed Metro Ethernet switches in the network guarantee the scalability of the network for at least 10 years.</jats:p
Scalable Column Generation Models and Algorithms for Optical Network Planning Problems
Column Generation Method has been proved to be a powerful tool to model and solve large scale optimization problems in various practical domains such as operation management, logistics and computer design. Such a decomposition approach has been also applied in telecommunication for several classes of classical network design and planning problems with a great success.
In this thesis, we confirm that Column Generation Methodology is also a powerful tool in solving several contemporary network design problems that come from a rising worldwide demand of heavy traffic (100Gbps, 400Gbps, and 1Tbps) with emphasis on cost-effective and resilient networks. Such problems are very challenging in terms of complexity as well as solution quality. Research in this thesis attacks four challenging design problems in optical networks: design of p-cycles subject to wavelength continuity, design of dependent and independent p-cycles against multiple failures, design of survivable virtual topologies against multiple failures, design of a multirate optical network architecture. For each design problem, we develop a new mathematical models based on Column Generation Decomposition scheme.
Numerical results show that Column Generation methodology is the right choice to deal with hard network design problems since it allows us to efficiently solve large scale network instances which have been puzzles for the current state of art. Additionally, the thesis reveals the great flexibility of Column Generation in formulating design problems that have quite different natures as well as requirements.
Obtained results in this thesis show that, firstly, the design of p-cycles should be under a wavelength continuity assumption in order to save the converter cost since the difference between the capacity requirement under wavelength conversion vs. under wavelength continuity is insignificant. Secondly, such results which come from our new general design model for failure dependent p-cycles prove the fact that failure dependent p-cycles save significantly spare capacity than failure independent p-cycles. Thirdly, large instances can be quasi-optimally solved in case of survivable topology designs thanks to our new path-formulation model with online generation of augmenting paths. Lastly, the importance of high capacity devices such as 100Gbps transceiver and the impact of the restriction on number of regeneration sites to the provisioning cost of multirate WDM networks are revealed through our new hierarchical Column Generation model
Proceedings of the 8th Cologne-Twente Workshop on Graphs and Combinatorial Optimization
International audienceThe Cologne-Twente Workshop (CTW) on Graphs and Combinatorial Optimization started off as a series of workshops organized bi-annually by either Köln University or Twente University. As its importance grew over time, it re-centered its geographical focus by including northern Italy (CTW04 in Menaggio, on the lake Como and CTW08 in Gargnano, on the Garda lake). This year, CTW (in its eighth edition) will be staged in France for the first time: more precisely in the heart of Paris, at the Conservatoire National d’Arts et Métiers (CNAM), between 2nd and 4th June 2009, by a mixed organizing committee with members from LIX, Ecole Polytechnique and CEDRIC, CNAM
Advanced Platform Systems Technology study. Volume 3: Supporting data
The overall study effort proceeded from the identification of 106 technology topics to the selection of 5 for detail trade studies. The technical issues and options were evaluated through the trade process. Finally, individual consideration was given to costs and benefits for the technologies identified for advancement. Eight priority technology items were identified for advancement. Supporting data generated during the trade selection and trade study process were presented. Space platform requirements, trade study and cost benefits analysis, and technology advancement planning are advanced. The structured approach used took advantage of a number of forms developed to ensure that a consistent approach was employed by each of the diverse specialists that participated. These forms were an intrinsic part of the study protocol
Summary of Research 1994
The views expressed in this report are those of the authors and do not reflect the
official policy or position of the Department of Defense or the U.S. Government.This report contains 359 summaries of research projects which were carried out
under funding of the Naval Postgraduate School Research Program. A list of recent
publications is also included which consists of conference presentations and
publications, books, contributions to books, published journal papers, and
technical reports. The research was conducted in the areas of Aeronautics and
Astronautics, Computer Science, Electrical and Computer Engineering, Mathematics,
Mechanical Engineering, Meteorology, National Security Affairs, Oceanography,
Operations Research, Physics, and Systems Management. This also includes research
by the Command, Control and Communications (C3) Academic Group, Electronic Warfare
Academic Group, Space Systems Academic Group, and the Undersea Warfare Academic
Group
Reports to the President
A compilation of annual reports for the 1999-2000 academic year, including a report from the President of the Massachusetts Institute of Technology, as well as reports from the academic and administrative units of the Institute. The reports outline the year's goals, accomplishments, honors and awards, and future plans