Ph.D. Thesis of Francisco Vasques:
Title:INTEGRATING SCHEDULING AND COMMUNICATION MECHANISMS IN THE MAC SUB-LAYER OF REAL-TIME LOCAL AREA NETWORKS
("Sur l'intégration de mécanismes d'ordonnancement et de communication dans la sous-couche MAC de réseaux locaux temps-réel")
LAAS technical report nº 96229, June 1996
Host Institution:UNIVERSITE PAUL SABATIER ( TOULOUSE III)
Research Laboratory:Laboratoire d'Analyse et d'Architecture des Systèmes du C. N. R. S.
LAAS - CNRS
7, avenue du Colonel Roche
31077 TOULOUSE Cedex
Abstract:In this thesis, we propose an architecture for the MAC sub-layer of a real-time communication network, which integrates scheduling and communication mechanisms to guarantee traffic timing constraints.
The thesis is organized as follows:
Firstly, the state-of-the-art of real-time MAC protocols are presented and classified, based on its real-time scheduling attributes. In particular, the timed token protocol and some mechanisms of the "IEC-65C" standard are detailed, since they are the foundation of the proposed architecture.
After, some contributions about real-time scheduling and it integration with real-time communication mechanisms are presented, such as: extension of the non-preemptive ED scheduling algorithm schedulability test; definition of a new mode change algorithm for RM scheduled networks; definition of a new timed token protocol, which enhances the traditional timed token protocol real-time performance; definition of schedulability tests for the FIP network sporadic traffic; proposal of two real-time profiles for the Profibus network.
Finally, an architecture for the MAC sub-layer of a real-time communication network is proposed, modeled and evaluated using Stochastic Timed Petri Nets. In this architecture, we propose the centralized scheduling of periodic and sporadic traffic. Such centralized scheduling is based on the non-preemptive scheduling of periodic traffic and on a timed token based scheduling of sporadic traffic. In this way, the traffic timing constraints are ensured.
Some traffic scenarios have been analyzed, using the Stochastic Timed Petri Nets model, which is an interesting tool to automatically evaluate the schedulability of generic message stream sets.
Keywords :Real-time scheduling; Real-time communication networks; Non-preemptive scheduling; Mode change; Timed token; Fieldbus; Stochastic Timed Petri Nets.
PDF Files:Chapter 1 ; Chapter 2 ; Chapter 3 ; Chapter 4 ; Chapter 5.