This is not unlike animals with layered nervous systems. Notice also that the upper layers of the subsumption architecture don t preclude the possibility of higher-level intelligence.
Computation consists of asynchronous networks of AFSMs.
There s a fixed topology of connections between AFSMs. Any communication path must be made quite explicit by specifying a wire. Processing is distributed making a central world model difficult to achieve. Numeric messages are sent over connections, arriving at input ports. The meaning of messages depends upon the purpose of sender and receiver.