Mobile Ambients with Timers and Types

Mobile ambients calculus is a formalism for mobile computing able to express local communications inside ambients. Ambients mobility is controlled by capabilities: in, out, and open. We add timers to communication channels, capabilities and ambients, and use a typing system for communication. The passage of time is given by a discrete global time progress function. We prove that structural congruence and passage of time do not interfere with the typing system. Moreover, once well-typed, an ambient remains well-typed. A timed extension of the cab protocol illustrates how the new formalism is working.