ocessing dimension in the description of the network. As seen from Figure 3.25 the other dimensions are a layered and a distributed dimension. What is called service management in the book corresponds roughly with the manage- ment of the solution above. 3.11.1 APPLICATION PROGRAMMING INTERACES AND SERVICE CAPABILITY SERVERS The application programming interface (API) is one of the key enablers, which enables the convergence and the creation of the new architecture. Understanding Changing Telecommunications - Building a Successful Telecom Business The network resources should be possible to define and access by the application developers. This has led to the introduction of APIs in the network. The first application is service enablers and other service network components with API interfaces. The API is defined as a set of technology independent interfaces in terms of procedures, events, parameters and their semantics and it is based on distributed computing concepts such as CORBA, Java and other technologies. A good API makes it easier to develop a program by providing all the building blocks. The programmer puts the blocks together. While open interfaces at the application level are the prerequisite for an open ser- vice architecture, it is important that applications' requests can be mapped appropriately onto the behaviour of the wireless network. Therefore open APIs are also needed at lower layers to enable customizations. Programmable networking aims at opening low- level access to network elements (routers, switches, base stations) by defining appropriate interfaces. These interfaces can then be accessed by various entities (protocols, agents) to offer advanced, customizable and collaborative network services. This concept can then be extended with mechanisms for distributing and executing code, which programs the interfaces on behalf of individual applications (including those running on end sys- items). The new paradigm has been called active networking. See Figure 3.36. A more telecom-oriented interpretat