nformation set on the MIB into commands for the NEs or reports for TM, is performed by agents and manager, respectively. TM Network Structure in the Distributed Dimension Technically, TM extends all over the network like a spider, collecting charging information and information about the traffic conditions through agents and information databases. Configuration and corrective commands are sent in the reverse direction. The fundamental technical plans are a guiding tool. Updated subscriber data is sent to servers/databases. See Figure 16.4. The basic management structure based on managers, agents, managed objects and MIBs, was simultaneously adopted both by IETF and ITU-T, during the early 1990s. Understanding Changing Telecommunications - Building a Successful Telecom Business This network model might induce one to think of a flat management network, without intermediate levels. As a matter of fact, this was the initial approach in the IP world, and still endures to some extent today. As mentioned, technology convergence is leading to bigger IP-based telecommunication networks but with hierarchical network structures (such as in TMN). The move towards IP in management communication is both the result of the Internet and packet switching success and improvements in IP security. The UMTS management network in Figure 16.7 illustrates this evolution. It has three different network management systems at sub-network level (radio access, core network and legacy GSM network). A simple management structure of a GPRS network is shown in Figure 16.8. TM Internal Architecture in the Layered Dimension The architecture can be presented as divided in three layers as shown in Figure 16.9. The presentation layer takes care of the interface with the operator providing a user-friendly environment and easy network-handling capabilities. Internet presentation technologies are used, with Java included to support application portability on different IT platforms. The service layer is responsible for the real interaction between manager