  Negotiations, introduced by Esparza et al., are a model for concurrent
systems where computations involving a set of agents are described in terms of
their interactions. In many situations, it is natural to impose timing
constraints between interactions -- for instance, to limit the time available
to enter the PIN after inserting a card into an ATM. To model this, we
introduce a real-time aspect to negotiations. In our model of local-timed
negotiations, agents have local reference times that evolve independently.
Inspired by the model of networks of timed automata, each agent is equipped
with a set of local clocks. Similar to timed automata, the outcomes of a
negotiation contain guards and resets over the local clocks.
  As a new feature, we allow some interactions to force the reference clocks of
the participating agents to synchronize. This synchronization constraint allows
us to model interesting scenarios. Surprisingly, it also gives unlimited
computing power. We show that reachability is undecidable for local-timed
negotiations with a mixture of synchronized and unsynchronized interactions. We
study restrictions on the use of synchronized interactions that make the
problem decidable.
