INFORMATION TECHNOLOGY Selected Tutorials IFIP – The International Federation for Information Processing IFIP was founded in 1960 under the auspices of UNESCO, following the First World Computer Congress held in Paris the previous year. An umbrella organization for societies working in information processing, IFIP’s aim is two-fold: to support information processing within its member countries and to encourage technology transfer to developing nations. As its mission statement clearly states, IFIP’s mission is to be the leading, truly international, apolitical organization which encourages and assists in the development, exploitation and application of information technology for the benefit of all people. IFIP is a non-profit making organization, run almost solely by 2500 volunteers. It operates through a number of technical committees, which organize events and publications. IFIP’s events range from an international congress to local seminars, but the most important are: The IFIP World Computer Congress, held every second year; Open conferences; Working conferences. The flagship event is the IFIP World Computer Congress, at which both invited and contributed papers are presented. Contributed papers are rigorously refereed and the rejection rate is high. As with the Congress, participation in the open conferences is open to all and papers may be invited or submitted. Again, submitted papers are stringently refereed. The working conferences are structured differently. They are usually run by a working group and attendance is small and by invitation only. Their purpose is to create an atmosphere conducive to innovation and development. Refereeing is less rigorous and papers are subjected to extensive group discussion. Publications arising from IFIP events vary. The papers presented at the IFIP World Computer Congress and at open conferences are published as conference proceedings, while the results of the working conferences are often published as collections of selected and edited papers. Any national society whose primary activity is in information may apply to become a full member of IFIP, although full membership is restricted to one society per country. Full members are entitled to vote at the annual General Assembly, National societies preferring a less committed involvement may apply for associate or corresponding membership. Associate members enjoy the same benefits as full members, but without voting rights. Corresponding members are not represented in IFIP bodies. Affiliated membership is open to non-national societies, and individual and honorary membership schemes are also offered. INFORMATION TECHNOLOGY Selected Tutorials IFIP 18th World Computer Congress Tutorials 22–27 August 2004 Toulouse, France Edited by Ricardo Reis Universidade Federal do Rio Grande do Sul Brazil KLUWER ACADEMIC PUBLISHERS NEW YORK, BOSTON, DORDRECHT, LONDON, MOSCOW eBook ISBN: 1-4020-8159-6 Print ISBN: 1-4020-8158-8 ©2004 Springer Science + Business Media, Inc. Print ©2004 by International Federation for Information Processing. Boston All rights reserved No part of this eBook may be reproduced or transmitted in any form or by any means, electronic, mechanical, recording, or otherwise, without written consent from the Publisher Created in the United States of America Visit Springer's eBookstore at: http://www.ebooks.kluweronline.com and the Springer Global Website Online at: http://www.springeronline.com Contents Preface vii Quality of Service in Information Networks 1 AUGUSTO CASACA Risk-Driven Development Of Security-Critical Systems Using UMLsec 21 JAN JURJENS, SIV HILDE HOUMB Developing Portable Software 55 JAMES MOONEY Formal Reasoning About Systems, Software and Hardware Using Functionals, Predicates and Relations 85 RAYMOND BOUTE The Problematic of Distributed Systems Supervision – An Example: Genesys 115 JEAN-ERIC BOHDANOWICZ, STEFAN WESNER, LASZLO KOVACS, HENDRIK HEIMER, ANDREY SADOVYKH Software Rejuvenation - Modeling and Analysis 151 KISHOR S. TRIVEDI, KALYANARAMAN VAIDYANATHAN Test and Design-for-Test of Mixed-Signal Integrated Circuits 183 MARCELO LUBASZEWSKI AND JOSE LUIS HUERTAS vi Information Technology: Selected Tutorials Web Services 213 MOHAND-SAID HACID Applications of Multi-Agent Systems 239 MIHAELA OPREA Discrete Event Simulation with Applications to Computer Communication Systems Performance 271 HELENA SZCZERBICKA, KISHOR TRIVEDI, PAWAN K. CHOUDHARY Human-Centered Automation: A Matter of Agent Design and Cognitive Function Allocation 305 GUY BOY Preface This book contains a selection of tutorials on hot topics in information technology, which were presented at the IFIP World Computer Congress. WCC2004 took place at the Centre de Congrès Pierre Baudis, in Toulouse, France, from 22 to 27 August 2004. The 11 chapters included in the book were chosen from tutorials proposals submitted to WCC2004. These papers report on several important and state-of-the-art topics on information technology such as: Quality of Service in Information Networks Risk-Driven Development of Security-Critical Systems Using UMLsec Developing Portable Software Formal Reasoning About Systems, Software and Hardware Using Functionals, Predicates and Relations The Problematic of Distributed Systems Supervision Software Rejuvenation - Modeling and Analysis Test and Design-for-Test of Mixed-Signal Integrated Circuits Web Services Applications of Multi-Agent Systems Discrete Event Simulation Human-Centered Automation We hereby would like to thank IFIP and more specifically WCC2004 Tutorials Committee and the authors for their contribution. We also would like to thank the congress organizers who have done a great job. Ricardo Reis Editor This page intentionally left blank QUALITY OF SERVICE IN INFORMATION NETWORKS Augusto Casaca IST/INESC, R. Alves Redol, 1000-029, Lisboa, Portugal. Abstract: This article introduces the problems concerned with the provision of end-to- end quality of service in IP networks, which are the basis of information networks, describes the existing solutions for that provision and presents some of the current research items on the subject. Key words: Information networks, IP networks, Integrated Services, Differentiated Services, Multiprotocol Label Switching, UMTS. 1. QUALITY OF SERVICE IN IP NETWORKS Information networks transport, in an integrated way, different types of traffic, from classical data traffic, which has flexible Quality of Service (QoS) requirements, to real-time interactive traffic, which requires QoS guarantees from the network. Most of the solutions for the transport of information in this type of networks assume that the networks run the Internet Protocol (IP), which provides a best-effort service. The best-effort service does not provide any guarantees on the end-to-end values of the QoS parameters, i.e. delay, jitter and packet loss. However, the best-effort concept results into a simple network structure and, therefore, not expensive. The best-effort service is adequate for the transport of classical bursty data traffic, whose main objective is to guarantee that all the packets, sooner or later, reach the destination without errors. This is achieved by running the Transmission Control Protocol (TCP) over IP. Services like e-mail and file 2 Augusto Casaca transfer are good examples of this case. The problem occurs when real-time interactive services, such as voice and video, run over IP. In this case, the achievement of an end-to-end delay and jitter smaller than a certain value is key to achieve a good QoS. This means that the best-effort paradigm needs to evolve within IP networks, so that new network models capable of efficiently transporting all the types of traffic can be deployed. The end-to-end QoS in a network results from the concatenation of the distinct QoS values in each of the network domains. In reality, these QoS values depend on the QoS characteristics of the different routers and links, which form the network. The QoS is basically characterised by the transfer delay, jitter and probability of packet loss, all relative to the traffic traversing the network. The end-to-end delay is caused by the store-and-forward mechanism in the routers and by the propagation delay in the links. Jitter, which is defined as the end-to-end delay variation for the distinct packets, is caused by the different time that each packet remains in the router buffers. Packet loss basically results from congestion in routers, which implies the discard of packets. The evolution of the best-effort paradigm to improve the end-to-end QoS in an IP network can be achieved by doing resource allocation at the router level, by intervening in the routing mechanism and by traffic engineering in the network. All these actions can be performed simultaneously in a network or, alternatively, only some of them can be implemented, depending on the QoS objectives. In the following text we will analyse these different mechanisms. The router structure in traditional best-effort networks, which is shown in figure 1, is very simple. Figure 1. Best-effort router Quality of service in Information Networks 3 The input ports accept packets coming from other routers and the output ports forward packets to other routers along the established routes. The forwarding unit sends each packet to the appropriate output port based on the IP destination address of the packet. For this purpose there is a routing table, which maps the destination address into the output port. The control unit is in charge of managing the forwarding unit. The routing protocol