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The Real Experiment eXecution Approach to
Networking Courseware

M. Chirico, F. Giudici, A. Sappia and A. M. Scapolla

Abstract - Courseware development and delivery represent one of the main topics of present research activities in the field of computer assisted learning (CAL). New educational technologies have been driven by the improvement in computer network capabilities that address client-server dynamics, access mechanisms and network services. Furthermore, multimedia authoring tools, the World Wide Web and the Java programming paradigm are leading to the creation of new and effective didactic environments. In this scenario, particular attention must be paid to the learning design process, since students can learn better when they are stimulated by a high level of interactivity and they can follow a personal way to learn. In this paper a new approach to Web-based courseware development is presented: the Real Experiment eXecution (REX) approach. The proposed approach is well-suited to the development of courseware in the field of computer science. Following the REX approach, it is possible to integrate into the courseware a high degree of interaction since, instead of simulation activity, real experiments are carried out through the execution of operations. The Java programming paradigm allows the execution, control and monitoring of these operations. We present a courseware prototype, featuring network services and protocols, where the students are introduced to the use of the FTP service. They start a file transfer session and execute typical commands. The system traces the generated network traffic and lets the students analyze and understand the results of the ongoing software experiments.

The growth of communication resources such as the Internet and the availability of authoring and distribution tools for computer-based learning products have changed the traditional way of supporting learning and training activities and of producing and distributing learning materials and publications. The research activities in Computer Based Training (CBT) delivery have taken advantage of computer network capabilities addressing client-server dynamics, access mechanisms and available network services.

The impact of information technology on teaching methods has been driven mainly by:

• the improvements in multimedia (MM) technology,
• the success of the World Wide Web (WWW) as a global-network of accessible information, and
• the Java programming language.

MM technology, based on the integration of hypertext with images, video, sounds, animations and simulations, is very suited to contemporary educational needs because of its intrinsic aspects such as modularity and multisensorial non-linearity.

The WWW represents a powerful medium with its intrinsic deliverability and its larger and larger diffusion through the Internet; therefore, it can serve as an effective educational environment as researchers incorporate their pedagogical tools into it.

Java has been defined by its designers as "a simple, object-oriented, network-savvy, interpreted, robust, secure, architecture neutral, portable, high-performance, multithreaded, dynamic language." Originally it was introduced mainly to develop distributed and network-centric applications. In particular, it now exhibits very high coupling with WWW technology. More specifically, Java allows the creation of small applications, ("applets,") that can be embedded easily in WWW pages, enhancing them with active capabilities.

A number of Java features are highly valuable for the development of WWW based courseware:

• Native networking support. Java was written explicitly for network deployment.
• Programming facilities. One of the primary goals in Java design is to relieve programmers of low-level tasks. For this purpose, it creates an intermediate layer between the application and the operating system, taking care of, for instance, operations such as memory garbage collection.
• Portability and Performance. Java programs are compiled into a "virtual machine" code (bytecode) that is interpreted. In this way Java programs are architecture-neutral and their portability is not an issue.
• Flexibility and Power. Java programs are naturally dynamic and can be extended easily with external modules.
• Robustness. Intrinsic Java robustness allows the creation of programs that are reliable in a variety of ways.

These features are valuable for a wide range of applications and also offer relevant benefits in the development of educational material, for both courseware designers and users:

• Benefits for courseware designers. The typical expertise of courseware designers is teaching, not programming: it is essential for them to concentrate on the data and the presentation model, thus avoiding the waste of time in low-level programming activities. Java programming facilities satisfy this need and their high performance allows the production of complex courseware.
• Benefits for courseware users. While robustness is intrinsically a plus for any kind of application programs, it is even more important for didactic software: an application that abruptly fails can induce disorientation in students, jeopardizing its pedagogical goals. It is also worth noting that the small footprint of Java executables reduces download times, a valuable benefit for courseware users connected through a modem.

• The Real Experiment approach (REX)
  • Basic concepts
  • System architecture
• A REX based networking courseware
• Conclusions and future work

• The Networking Courseware
• An example: REX teaches TCP/IP and some high-level protocols (FTP, DNS, ARP)
• The REX Interface
• The Courseware Preview

• Introduction to the demo

We wish to thank Marco Terrizzano for his valuable suggestions about the demo interface.

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M. Chirico
Networking Competence Center
University of Genoa - DIBE
via All'Opera Pia 11/A - 16145 Genoa
Italy
Phone: +39-10-3532267
Fax: +39-10-3532795
E-mail: chirico@dibe.unige.it

F. Giudici
Networking Competence Center
University of Genoa - DIBE
via All'Opera Pia 11/A - 16145 Genoa
Italy
Phone: +39-10-3532192
Fax: +39-10-3532175
E-mail: fritz@dibe.unige.it

A. Sappia
Networking Competence Center
University of Genoa - DIBE
via All'Opera Pia 11/A - 16145 Genoa
Italy
Phone: +39-10-3532192
Fax: +39-10-3532175
E-mail: sappia@dibe.unige.it

A. M. Scapolla
Networking Competence Center
University of Genoa - DIBE
via All'Opera Pia 11/A - 16145 Genoa
Italy
Phone: +39-10-3532193
Fax: +39-10-3532175
E-mail: ams@dibe.unige.it

Biographies

Marco Chirico was born in Turin, Italy in 1957. He received a laurea degree in electronic engineering from the University of Genova, Italy, in 1983. Since 1986 he has been working at the Center for Integrated Systems Design of the Department of Biophysical and Electronic Engineering (DIBE) at the University of Genova. In recent years his research interests included parallel algorithm design, CAD tools for VLSI systems and high level synthesis of ICs. Presently he is involved in research activities on telematic applications for networking. He also coordinates the network services of the Department.

Andrea Sappia was born in Sanremo, Italy in 1967. He obtained the laurea degree from the University of Genova in 1995. Presently, he is a Ph.D. student at the Department of Biophysical and Electronic Engineering at the University of Genova, Italy. His primary research interests are network and system management and distributed programming.

Fabrizio Giudici Fabrizio Giudici was born in Genova, Italy, in 1970. He obtained the laurea degree from the University of Genova in 1994. Presently he is a Ph.D. student in the Department of Biophysical and Electronic Engineering at the University of Genova, Italy. His primary research interest is distributed programming using the Java paradigm.

Anna Marina Scapolla was born in Cuneo, Italy in 1951. She received a laurea degree in Physics from the University of Genova in 1975. Since 1976 she has been working at the Computer Center of the university as an application analyst. Since January 1994, she has been on the staff of the Department of Biophysical and Electronic Engineering, where she supervises the network services in the department. Her research interests are multimedia and education, high performance computer networks and distributed information systems.