Abstract: This paper presents a tool for MPLS network dimensioning that allows for multi-hour dimensioning of networks supporting simultaneously peer-to-peer and client-server services. The dimensioning model is able to take into account several LSP attributes: degree of survivability (link disjoint and node disjoint cases), maximum hop count, usable colours and preferred routes. The dimensioning problem is a combined capacity design and routing problem where the LSP sets are calculated in order to minimise the network operational costs. This problem is formulated as an integer programming problem, which is solved through an heuristic based on Lagrangean relaxation with sub-gradient optimisation. The network design tool, named PTPlan MPLS, includes a graphical interface for an easy introduction and edition of the network parameters. Results show that the tool can design networks of realistic size in seconds using a standard PC platform.