Davide Cherubini - PhD Thesis - UniCA Eprints

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7.4 The Real ISP’s Italian Backbone Network7.4 The Real ISP’s Italian Backbone NetworkThe final test of the LP optimization model has been performed over the Italianpart of Tiscali International Network (TINet) [21].The network is composed of 18 nodes and 54 arcs with different maximum capacitythat, at the moment of tests, ranges from 1 Gbps to 2.5 Gbps.The traffic matrix, composed by 306 flows, has been built thanks to the willingnessand the collaboration of the ISP’s network operators and managers.The resulting model is made of 1279 variables and 1402 constraints and it hasbeen solved either as GRP or taking care of the survivability constraint. Theobtained results have been compared with the “default” configuration, with theISP’s IS-IS metrics configuration, those used by the network operator in normalworking condition, and with the IS-IS metrics obtained from the metaheuristicoptimization process.Figure 7.9: Tiscali International NetworkThe characteristics of the TINet network are summarized in Table 7.6, whilethe whole Tiscali International Network logical topology is depicted in Figure 7.9.75
7.4 The Real ISP’s Italian Backbone NetworkNodes 18Arcs 54Flows 306Variables 1279Constraints 1402Table 7.6: Characteristics of the Tinet Italian backboneRouting OptimizationThe objective function value comparison shown in Table 7.7 highlights the congestionlevel reduction granted by the optimization processes.In particular, the MPLS optimization allows dropping the maximum utilizationby 10.6%, with respect to the ISP’s IS-IS configuration, using only 105 LSPs.Histograms report the occupation of the links in three different scenarios:• ISP’s IS-IS metrics (Figure 7.10)• IS-IS optimized metrics (with Tabu Search) (Figure 7.11)• MPLS optimization (Figure 7.12)Phase u max % Gain (Def) % Gain (Tis) # LSPDefault u max = 72% – – 0Tiscali u max = 66% 8.3% – 0IS-IS opt. u max = 61% 15.2% 7.6% 0MPLS opt. u max = 59% 18.1% 10.6% 105Table 7.7: Routing optimization for the Tinet network76
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AcknowledgementsThis dissertation w
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AbstractThis dissertation investiga
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CONTENTS7.4 The Real ISP’s Italia
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LIST OF FIGURES7.3 Default metrics
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1.2 Objectives of the dissertation2
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Chapter 2Basic knowledgeThis chapte
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2.1 Understanding IS-IS• A = sour
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2.2 Understanding MPLS Technology2.
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2.2 Understanding MPLS TechnologyTh
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2.4 Restoration SchemesHowever, fai
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3.1 Optimization of IS-IS/OSPF rout
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3.3 Survivability problemhas been d
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4.1 Heuristic Algorithmsmeta-heuris
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4.1 Heuristic Algorithmsto keep a c
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Page 57 and 58: 6.2 Graphs and Network FlowsWhere B
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Page 65 and 66: 6.4 LP modelsEquation 6.32 is the o
Page 67 and 68: 6.4 LP modelsmalized as follows:z =
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Page 97 and 98: REFERENCES[14] Jones Lustig Format
Page 99 and 100: REFERENCES[40] A. V. Fiacco and G.
Page 101: REFERENCES[61] A. Nucci, B. Schroed
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Davide Cherubini - PhD Thesis - UniCA Eprints

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