Colloque avec actes et comité de lecture. internationale.International audienceIn this paper, we compare the use of two packets models in slotted optical ring networks: a model where each message has to be routed in consecutive slots, and a model where the slots can be routed independently. We first focus on the algorithmic complexity of the related problems. Then, we give the results we obtain with an OMNET simulator in terms of messages delay and jitter and of communication resources really used at each step