The five W's of the paradigm: What Why hoW When Who
Why is flexibility important ?
In the domain of industrial communication systems, flexibility is considered a way to:
Reduce costs associated to set-up, configuration changes and maintenance
Improve the resource efficiency usage
Resources can be allocated in a "as needed basis" fashion
No over-provision is required
Online QoS management is possible
Manage system complexity
No need to predefine an exhaustive (but necessarily limited) set of modes
Support to open/dynamic environments
Increasing number of inherently dynamic applications, in which nodes join and departure at runtime
What is flexibility ?
Flexibility means the "ability to make changes or to deal with a situation that is changing" (Macmillan dictionary)
For industrial communication networks flexibility translates to:
Add and/or remove message streams
Modify attributes on existing message streams
E.g. change the period or deadline
Support different traffic types ( Time-Triggered, Event-Triggered) with different criticality levels (Real-Time, Non Real-Time)
Support the plug/unplug of nodes from the network
All of this online and without disrupting communications!
How to support flexibility while guaranteeing real-time requirements ?
Flexible Time-Triggered Architecture
Centralized architecture to coordinate the network, composed of :
A System Requirements Database (SRDB)
An online scheduler that operates on the SRDB
A set of primitives to update the SRDB
An online admission control that rejects non-feasible changes
An (optional) online QoS manager and a mechanism to broadcast the schedule through the network
Who and When ?
Flexible Time-Triggered Timeline
The Flexible Time-Triggered protocol family has been essentially developed at the University of Aveiro, by the Electronic Systems Laboratory team,
since 1998.
