Hard Real Time Communication Using the CANIOP Protocol

Distributed computer control in complex embedded systems oversees diverse electronic control units connecting hundreds or thousands of analogue and digital sensors and actuators. These systems are also called today sensors networks. In an emrging class of open distributed real time and embedded (DRE) systems with stringent but dynamic QoS requirements, there is a need to propagate QoS parameters and enforce task QoS requirements across multiple endsystems in a way that is simultaneously efficient and adaptable. Consequently, this paper presents an inter-ORB protocol, which makes efficient use of the advantages of controller area network (CAN) and maps the CAN priorities to a band of CORBA priorities. Our definition of this protocol is bound closely to the features of RT-CORBA, the OMG data acquisition from industrial systems(DAIS) RFP and the CAN bus, well known as a real-time underlying network . We give the criteria of the definition of the priority field and show how prioritization of messages over the physical CAN network can be achieved, when adopting the use of RT-CORBA scheduling service which implements a dynamic scheduling policy.