11.1 Introduction

There are two major revolutions going on in the world of telecommunications today the widespread deployment of mobile communications services and the emergence of IP-based multimedia applications. On fixed networks, increasingly large amounts of the total traffic carried by operators, such as BT, is now data traffic. In addition, data traffic is now many times the current level of voice traffic with Internet traffic, in particular, estimated to be doubling every 7 months. When examined more closely, virtually all this data traffic emanates from IP-based applications even though it might be carried over ATM, SDH or private circuits in the public network. This growth in traffic is in part due to the World Wide Web and the deployment of corporate intranets, such as the BT Intranet, which are increasingly used for all forms of information dissemination and business applications. For example, the BT Intranet hosts many IP-based applications that, among other things, allow employees to order supplies, look up contact details for other employees, manage projects, view lectures, conduct training, watch BT business TV broadcasts, share documents and perform many other business-related functions. This revolution in IP-based data traffic has initially been fuelled by a number of factors including:

• the emergence of new charging strategies, such as flat-rate Internet access;

• ubiquitous and affordable computing due to the great reduction in PC costs;

• the availability of licence-free source code;

• a potentially rapid and pragmatic standardisation process for Internet technology;