Figure 3.10 The starting point: tele-centric networks, data-centric networks and media industry content - no convergence Understanding Changing Telecommunications Building a Successful Telecom Business Common connectivity Voice-centric core network Other data-centric networks networks (Frame relay) Figure 3.11 The first signs of integration and convergence: multi-service application of ISDN and ATM Capacity with separate networks Capacity with multi-service networks Required capacity Saved capacity Required capacity Time of day Time of day Morning Afternoon Evening Morning Afternoon Evening Figure 3.12 When the bearers can manage both tele- and data-centric services, capacity can be saved for other data traffic for more than 30 years, supported by an impressing development of modems. ATM has offered efficient multi-service use of the transport capacity. See Figures 3.11 and 3.12. In Figure 3.12, the upper curve on the left-hand side represents data traf- fic and the lower curve represents voice traffic. Both curves and the sum of the two curves appear on the right-hand side. In this situation we want to use the investments as much as possible. Further we need an adaptation between the purpose-built networks and a service/application layer, which is independent of available access/bearer networks. Roughly we get the traditional voice-centric and data-centric networks converging with service/application-oriented part, offering information retrieval and streaming services. 3.4.3 TRANSITION FEATURE 3 The Convergence Glue: IP From a traffic point of view the original interactive and symmetric voice-dominated com- munication is complemented with, and in fact overtaken by, a client-server IP-based asymmetric traffic pattern. See Figure 3.13. This bursty pattern usually implies more traffic from the server than from the client. Behind the server-generated traffic one can find the media industry and other parties in the IT society as content providers. The various ways Networks and Technologies Server Portals Client Clien