Future Network based Operations (NbO) will necessitate new approach to deal with assymetric context, urban area and tactical mobility. These operations will have to cope with multiple collaborative actions in a complex and changing environment. In NbO, collaborative actions stresses coordination and synchronisation requirements, both in terms of complexity and tempo. Consequently, NbO deeply impacts plan elaboration and task scheduling processes performed by the different units. This paper presents a constraint-based method for automating mission planning and scheduling services in the context of Network based Operations. The approach is experimented on realistic benchmarks and during the Phoenixpsila07 experiment. Results show that mission planning and scheduling tools can be used to develop, experiment and evaluate the NbO concept.