translate the security requirements into the telecom- munication field. This could be done in various ways. One approach chosen for this book is to use the same tool as in Chapter 3: the fundamental technical plans (Figure 6.10). Another one is to use the 'stack'. The first measure is explained in Chapter 3: to integrate security within the fundamental plans. To make a parallel with QoS, it would have been logical to call the security area SoS, security of service (for the user), or security of system (for the actor). The next measure is to look at the nature of attacks in a broader way. What is really being attacked? Figure 6.10 can be developed into Figure 6.11. Let us use this FP figure to illustrate the attacks. Billing Telecom business Service Service, Service security Service layer management Numbering Dimensioning Charging Routing Signalling Control layer Dependability Mobility management Switching Frequency Transmission Traffic resources Synchronization in connectivity layer Organization M = Management system Traffic system = Network Figure 6.10 Security is in this book seen as a fundamental technical plan (among other views) Security Content Attacks anywhere! Security Added Service layer capabilities value Service Control management Service Mobility Charging Signalling manage- Attacks! Switching Dimensioning Numbering routing (control and Availability connectivity Synchronization Connectivity resources) resources Network management Traffic Frequency Transmission Organization Figure 6.11 Fundamental technical plans are target for attacks The IP control plane: the attacks can hit the addressing functions. The domain name system (DNS) is the directory service inside the Internet. It is the DNS that translates a WWW or IP address (for example 10.30.100.45). Suppose that an intruder wants to manipulate the DNS database. If possible, then a user may think that he is communicating with his bank, while in fact he is communicating with the intruder system (which could be a copy of the bank's home page). In this w