**3.3 Lessons learned**

206 Telecommunications Networks – Current Status and Future Trends

Fig. 21. The published telecommunications service domain ontology.

considered.

**3.2 Use cases: Semantic telecommunications network capability services** 

In order to support the shift from traditional closed business model to open service ecosystem of telecom industry, NGN (Next Generation Network) and 3G network all adopt the open API (Application Programming Interface) technologies in the service layer, such as Parlay/OSA and Parlay X (Moerdijk & Klostermann, 2003). Thus, the telecommunication network services, such as call control, short messaging service, and location service, are available to the service developers in the form of APIs. This facilitates the value-added service development. With the development of distributed computing technology, Service-Oriented Architecture (SOA) is also imported into the telecommunications service domain by Parlay Web Service specifications. However, the open interface specifications of telecommunication networks are currently still in the syntactic level. As WSDL (Web Services Description Language)-based telecommunication network services lack the rich semantic annotation information, the keyword-based service matching cannot enable an accurate service discovery. So, currently value-added services often directly invoke the needed telecom network services provided by a specific network carrier. This results in the tight-coupling of application logic and service resources, which limits the provision of dynamically self-adaptive services. The applications cannot dynamically discover satisfied telecom network services and compose them according to the context environment. Facing the heterogeneous networks and personalized user demands, the self-adaptation has become a very important feature of future intelligent integrated service. Therefore, the semantic interoperability of telecom network and Internet in the service layer should be Currently, under the shift trend from Web2.0 to Web3.0 era, there have been some initial semantic web applications in Internet field. For example, the system of Twitter allows tweets to be tagged with information that will not appear in the message but can be read by computers (Twitter, 2010). Google is using structured data open standards such as microformats and RDFa to power the rich snippets feature. It's an experimental Semantic Web feature (Google, 2010). FOAF (Friend of a Friend) (FOAF, 2010) is a machine-readable ontology describing persons, their activities and their relations to other people and objects. As a "practical experiment" in the application of RDF and Semantic Web technologies to social networking, FOAF is becoming more and more popular now (FOAF, 2000). In addition, Linked Data (Linked Data, 2007) is a recommended best practice for exposing, sharing, and connecting pieces of data, information, and knowledge on the Semantic Web using URIs and RDF.

However, the semantic web applications in telecommunication services domain are still in an early research phase. Although RDF-based CC/PP (Composite Capability/Preference Profiles) (W3C, 2007) and UAProf (User Agent Profile) (OMA, 2001) are used to describe the terminal capability and user preference, other practical applications are very rare. Therefore, in order to eliminate the semantic gap between telecom network and Internet, the research on semantic web applications in telecommunications field still need to be further enhanced. Telecommunications service domain ontologies consist of various domain related concepts and knowledge, which is the base of semantic interoperability. The wide acceptance of standards and common practices of telecommunications service domain ontologies are still a way ahead. The promotion of the telecommunications service domain ontology by related standardization organizations would be in the foundation for the semantic interoperability of heterogeneous communications equipments and the industrial practical convergent service integration.
