This paper describes an event model that has been designed to address the predictability requirements of applications operating in mobile environments based on hierarchically structured WAN-of-CANs networks. The event model supports an event channel concept for modeling the guarantees provided by the underlying heterogeneous communication infrastructure. The networks that comprise such a WAN-of-CANs may provide fundamentally different degrees of quality of service and as a result can be viewed as zones within which certain guarantees can be enforced. Event channels operating in CAN-based subnetworks typically with strong timing behavior may support hard temporal and reliability attributes whereas channels interconnecting these subnetworks using wireless networks support weaker timing attributes.