In-vehicle embedded systems typically consist of a set of nodes exchanging applicative data (signals) through a stack of communication protocols that includes a middleware layer. On each node, tasks, both applicative and middleware level, are subject to deadline constraints. Furthermore, signals must be produced sufficiently recently for being safely consumed on the receiver end (so-called freshness constraint). The goal of this study is to propose an approach for configuring nodes and communication protocols that takes these constraints into account. Precisely, the problem is, on the one hand, to set the characteristics of the middleware tasks and of the set of frames and, on the other hand, to find a feasible schedule on each node.