Virtual LAN-WAN for Workgroup Multimedia Application1

Workgroup multimedia applications such as videoconference, teleteaching or CSCW demand multipoint service from Telecommunication Networks. This is not just a broadcast service but it is a service where N sites transmit traffic to N sites. This service requires that the network support a large number of work-groups with few (5-20) participants together with low delay, low delay jitter, high throughput and a con-nection-less service in a wide area. The service of required by each of these workgroups is what we call Virtual LAN-WAN (VLW). At present, most of these multimedia applications have been developed over the IP protocol. Asynchro-nous Transfer Mode (ATM) will be the technology of the future Broadband Integrated Services Digital Network (B-ISDN), so ATM Networks must provide a framework for the development of multimedia applications based on IP protocols. In fact, the integration of IP over ATM Networks is as subject of intense work in standardization bodies. Within this effort, the ATM Forum and the Internet Engineering Task Force (IETF) have achieved some results in the provision of LAN service based on IP over ATM. This paper shows the problems of supporting a VLW service based on IP protocol over ATM Networks. We summarize the ATM Forum model based on LAN Emulation Specification (LANE) and the work in progress of the IETF on this subject. Pros and cons of every solution are described, and a model consid-ered to provide cost-effective performance is proposed. Finally, we present a case study that has been tested in a European scale. This case study is a distributed conference based on the ATM paneuropean pilot interconnecting ten sites in seven countries. Keywords: IP, ATM, multicast, groups, LANE, MARS, traffic, costs, management