The design of service networks is central to freight transportation, directly affecting cost efficiency, service reliability, and competitiveness. Tactical Service Network Design (SND) models determine which services to operate and how to configure them to satisfy demand at minimum cost. However, these models typically assume a static, single-period context, limiting their ability to capture evolving networks and commercial commitments.

This work is motivated by the operational challenges of Log'issimo, the B2B logistics subsidiary of La Poste, which must plan a transportation network over time. Their system combines long-haul services operated by external carriers with strategic decisions on contract acceptance and commodity delivery. A key feature of their offering is that each commodity must follow a single end-to-end path. These tightly coupled decisions fall outside the scope of classical SND models, motivating the development of a multi-period, contract-aware optimization framework.

The Contract-Aware Multi-Period Service Network Design (CA-MPSND) problem formalizes this setting by jointly optimizing:
(i) contract selection, (ii) service activation with varying durations and capacities, and (iii) commodity routing. The objective is to maximize profit by balancing contractual revenues with fixed and variable costs while ensuring contract-level guarantees are satisfied.