Model checking is now widely used as an automatic and exhaustive way to verify complex systems. However, this approach suffers from an intrinsic combinatorial explosion, due to both a high number of synchronized components and a high level of expressivity in these components. With respect to the expressivity issue, we consider the particular problem of introducing explicit time constraints in the components of a system. In this modeling step, the choice of a time domain is important, impacting on the size of the resulting model, the class of properties which can be verified and the performances of the verification. In this presentation, we show that hierarchical encoding of elementary com- ponents encapsulating labeled transition systems (LTS), synchronized by means of public transitions, is an efficient way to encode discrete time.