Abstract
Addresses the problem of transmitting real-time periodic traffic in a DQDB network. In a DQDB network, connection-oriented isochronous services use the pre-arbitrated (PA) access. The standard specifies that isochronous connections must have guaranteed periodic bandwidth but mechanisms to provide it, such as the slot allocation scheme, are not described. We propose a real-time service provider (RTSP) based on the use of the PA access. The RTSP consists of an off-line centralized scheduling algorithm and an on-line mode change algorithm which allows to take into account load changes. Means are also provided to guarantee a minimum fairness level for the asynchronous traffic. © 1994 IEEE.

Abstract
The IEEE 802.15.4 standard provides a flexible communication approach for LR-WPAN networks. When active, the beacon-enabled mode allows real-time communication by adopting a GTS (Guaranteed Time Slot) mechanism. However, this mechanism supports only up to seven real-time communicating devices. Motivated by this problem, this paper proposes the use of a dynamic GTS scheduling approach based on the (m,k)-firm task model, to deal with the GTS starvation problem. The proposed approach ensures that, for each admitted message stream S-i at least m messages will be transmitted within each window of k consecutive deadlines. The effectiveness of the proposed scheduling approach is demonstrated by a set of simulation and experimental results. The proposed approach is fully compatible with the IEEE 802.15.4 standard.

Abstract
Low-power wireless communication protocols have been shown to experience a significant timeliness and reliability degradation under certain interference profiles. Provided that this impairment has hindered their wide adoption in demanding real-time scenarios, the Wireless Flexible Time Triggered (WFTT) protocol has been recently proposed targeting applications with stringent timeliness requirements. This protocol builds on the medium access determinism granted by the bandjacking technique in open environments, where different technologies may contend for the medium. Besides providing a deeper definition of the WFTT architecture and protocol operation, this paper presents a thorough analysis addressing its implementation feasibility.

Abstract
The Controller Area Network (CAN) is a fieldbus network with real-time capabilities. It is generally considered that CAN guarantees atomic multicast properties, through its extensive error detection/signalling mechanisms. However, there are error situations where messages can be delivered in duplicate by some receivers or delivered only by a subset of the receivers, leading to inconsistencies in the supported applications. In order to prevent such inconsistencies, a set of atomic multicast protocols is proposed, taking advantage of CAN synchronous properties to minimise its run-time overhead. This paper presents such set of protocols, focusing on the timing analysis of the supported reliable real-time communication. It demonstrates that, in spite of the extra stack of protocols, the real-time capabilities of CAN are preserved, since the predictability of message transfer is guaranteed.

Abstract
It is generally considered that the Controller Area Network (CAN) guarantees atomic broadcast properties through its extensive error detection and signalling mechanisms. However, it is known that these mechanisms may fail, and messages can be delivered in duplicate by some receivers or delivered only by a subset of the receivers. This misbehaviour may be disastrous if the CAN network is used to support replicated applications. In order to prevent such inconsistencies, a set of atomic broadcast protocols is proposed, taking advantage of CAN synchronous properties to minimise its run-time overhead. This paper presents such set of protocols, and demonstrates how they can be used for the development of distributed real-time applications.

Abstract
In Distributed Computer-Controlled Systems (DCCS), both real-time and reliability requirements are of major concern. Architectures for DCCS must be designed considering the integration of processing nodes and the underlying communication infrastructure. Such integration must be provided by appropriate software support services. In this paper, an architecture for DCCS is presented, its structure is outlined, and the services provided by the support software are presented These are considered in order to guarantee the real-time and reliability requirements placed by current and future systems.