Dealing with time constraints in the design of distributed real-time systems is a challenge in the future trends on distributed computing. Time constraints must be considered, projected and derived onto all the layered structure components of the distributed system. This time constraints consideration, projection and derivation must be also done along all the stages of the life cycle. We focus how time constraints are involved in cooperation and communication aspects. We show one way to express time constraints with a temporal logic oriented specification, and some operating mechanisms to deal with them at the implementation stage.