Session Survivable Network Design MPLS Network Design

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					                            Session: Survivable Network Design

       MPLS Network Design with Fault-Tolerance and Hop Constraints
                                         Pedro Patrício 1,(a)

                                          Luís Gouveia 2,(a)

                                          Amaro de Sousa 3
       Departamento de Matemática, Universidade da Beira Interior, 6200 COVILHÃ, Portugal
                        and Centro de Investigação Operacional – FCUL

                         Universidade de Lisboa, Faculdade de Ciências, DEIO
                            BLOCO C6, Piso 4, 1749-016 Lisboa, Portugal
                          and Centro de Investigação Operacional – FCUL
       Instituto de Telecommunicações , Universidade de Aveiro, 3810–193 AVEIRO, Portugal


Given the location of edge nodes, the candidate locations of core nodes and the pairs of
locations that can be physically connected, the MPLS network design problem is the
determination of the physical network topology, i.e., the location of core nodes and the
connections required between all nodes. The aim of the design task is to determine the least cost
The physical network must support routing paths between all pairs of edge nodes fulfilling two
types of path constraints. The first type is a MPLS hop constraint on the maximum number of
nodes traversed by each routing path, which guarantees a given packet level quality of service
(QoS). The second type is the fault-tolerance constraint. An important component of providing
QoS is the service reliability and a fault-tolerance scheme must be present in the network to deal
efficiently with failure scenarios. In this work, two edge-disjoint routing paths are considered
for each pair of edge nodes. This method is the basis for some fault-tolerance schemes like the
1:1 and 1+1 protection mechanisms or the two-path diversity routing mechanism.
We compare three Mixed Integer Programming formulations for the problem described above.
We shall present computational results, taken from graphs with up to 50 nodes and 500 edges.

Keywords: MPLS network design, survivability, hop constraints

(a) Supported by POCTI-ISFL-1-152