The ShoreTel system is based on a unique call-control architecture that distributes call processing across every voice switch in the network. There is no single point of failure with this approach, and it allows for high system availability.

Each switch can function as a standalone system, providing each branch with autonomy, while multiple switches in a network can provide back up. The ShoreTel system at least matches and potentially exceeds the "five nines" (99.999%) availability of traditional voice systems, and yet offers the efficiency and economy of a plug-and-play replacement.