WWW and e-mail. Figure 3.16 shows an important feature of IP networks, which is to utilize and achieve internetworking across other networks. By the way IP is no longer just global; it is used for interplanetary communication between the earth and Mars. Understanding Changing Telecommunications - Building a Successful Telecom Business Servers Portals Adaptation to information society: Packetized voice for Service Extended use of the Cu-pair multi-service and multimedia provider PLMN 2G 2.5G 3G (VolP GPRS packet data channel UMTS WCDMA path VoATM Cable TV Hybrid fibre coax Figure 3.14 New enablers for convergence Two Internet industries are being formed Fixed Internet Mobile Internet Always with you, Common positioning Broadband applications applications applications Portals Service provider MM/IP MM/IP MM/IP Various layer 2: PPP, ATM, FR, Packet over Sonet... Figure 3.15 Multimedia over IP combined with mobile and fixed Internet Content provider and other roles Multiple 'virtual' IP networks Service network, Internet, Access Transport corporate network IP host/client IP routing IP host/server Figure 3.16 IP - the network glue Networks and Technologies 3.5 WHAT IS A HORIZONTAL NETWORK? This concept of layered network architecture is already in use in datacom networks, SO it is not brand new. The development within the telecom industry during the last decade has underlined that the future range of successful services is impossible to predict. Bearing this lesson in mind, network architects are highly aware of the need to build the networks as flexible service platforms. The number of services increases quickly, especially because of the paradigm shift when the telecom, datacom and media industries converge. Together with fast technical development, this provides a background to the changing architecture of networks in the telecom world, from what is frequently called the vertical networks of the past and present, to the horizontal networks of the future. The development is supported by operators, service providers,