  We consider the model checking problem of infinite state systems given in the
form of parameterized discrete timed networks with multiple clocks. We show
that this problem is decidable with respect to specifications given by B- or
S-automata. Such specifications are very expressive (they strictly subsume
omega-regular specifications), and easily express complex liveness and safety
properties. Our results are obtained by modeling the passage of time using
symmetric broadcast, and by solving the model checking problem of parameterized
systems of un-timed processes communicating using k-wise rendezvous and
symmetric broadcast. Our decidability proof makes use of automata theory,
rational linear programming, and geometric reasoning for solving certain
reachability questions in vector addition systems; we believe these proof
techniques will be useful in solving related problems.
