1. Tools for collaborative e-activities G. Adorni, F. Bergenti, D. Bianchi, A. Poggi, M. Somacher G. Adorni Università di Genova e-mail: [email_address] F.Bergenti, D. Bianchi, A. Poggi, M.Somacher, Università di Parma, e-mail: {bergenti,bianchi,poggi,somacher}@ce.unipr.it

2. Tools for collaborative e-activities This paper discusses a system to facilitate activities through the network (e-activities) offering tools for collaborative work, video conferencing and video on demand . The architecture of the system is composed by two levels. The first level, called collaborative level , allows remote users to take part to a meeting where they can interact with each other via a chatting line and by sharing the use of different applications. A second level, called multimedia level , allows a multimedia interaction between the members of the meeting. Each user must own a microphone, a CCD camera and an internet connection with a sufficient bandwidth to support the exchange of audio and video data. We present some results obtained during research activities (project meetings, software design and debugging, document writing) involving people connected from different towns of Italy. The system was also used in e-learning activities distributed through a campus local network.

20. The campus network We have two different networks. The first is the TCP/IP intranet of the Campus. This network is normally used for all the activities of the basic and collaborative levels, i.e., access to the Web server, to the mail and news services, to the chatting line and tools for collaborative work. The Campus network can support those services that do not require a fixed bandwidth allocation. On the contrary, multimedia service needs a guaranteed wide band connection to transmit video or audio data. So, a second network based on ATM technology connects the video server with the classrooms and labs.

21. The campus network The ATM network connects the video server with classrooms and laboratories. It is supported by a PON (Passive Optical Network) with a bandwidth of 622 Mbit/sec download and 155 Mbit/sec upload. The fiber optical network is connected with the user equipment using an ADSL switch which is also connected to Campus Intranet (Fast Ethernet).

25. The Collaborative PrologLab Interface Participants can edit and test programs, use a chat line, enter or exit session, request or release the floor.