Abstract Author Ignacio Gonz¶alez Ol¶‡as Title of the Thesis Security and auto-conflguration of Location

IP networks were designed to provide an e–cient and robust mechanism for transferring data between remote computers. Initially, the information exchanged was mostly computer related data: text documents, flles, web content, etc. However, the increasing popularity of this kind of networks is encouraging the development of new services and applications that take advantage of the existing infrastructures. One of the emerging applications is IP telephony, a new service aimed to al-low end users to complete voice calls over IP networks. This a clear example of how a service that was traditionally ofiered using a difierent technology, i.e. public switched telephone networks (PSTN), has been adapted to the IP networks. Since the migration from one approach to another can not take place overnight, both technologies will be interacting for a period of time. This in-teraction generates new interoperability problems that must be addressed. Data and signalling conversion between both networks is performed by spe