ensure that users can use any information resource whenever and wherever it is needed in accordance with applicable privileges'. An authorized party should not be prevented from accessing objects to which he/she/it has legitimate access. For example, a security system could preserve perfect confidentiality by preventing everyone from reading a particular object. However, this system does not meet the requirement of availability for proper access. Availability is sometimes known by its opposite, denial of service. The user wants, with maybe the highest priority, a very high availability from a telecommunication system, sometimes expressed with a series of nines, such as 99.99 %. This requires a working and accessible system, one that is not severely disturbed by physical damage, viruses etc. A particularly serious threat is offered by unauthorized staff taking control of man- agement systems for the operation of a network. A thorough authentication is therefore required before allowing commands from the management system to operate on a traffic system. Despite the complexity and importance of the management system most of the content of this section will deal with traffic-related protection. Goal for the Actor The purpose of the security plan and measures is to provide reasonable assurance to the user of the integrity and confidentiality of information, and availability of network resources, servers and services. 6.3 THE PROBLEM The public Internet is increasingly used to access security-critical services like banks and e-commerce. Technically, the public Internet is, however, an unreliable network with many possibilities for an intruder. And on top of an insecure IP network, we usually run insecure applications. Understanding Changing Telecommunications - Building a Successful Telecom Business Potential threats are illegal access to information, inadequate identification of users and resources, tampering with information, masquerading, eavesdropping, subscription fraud, non-payment for services, bypassing securit