The Internet faces ever faster and stronger dynamics in the behavior patterns of its users and hence, in the imposed load and traffic. However, the various ‘mechanisms’ used within the Internet—communication protocols and their functional components, overlays, middleware, etc.—cannot be sufficiently adapted at runtime: parameter adaptation is common practice, but the replacement of a mechanism by one that is functionally similar yet more appropriate—for the benefit of performance and quality—is rare. Those rare cases are tediously engineered case by case since on-the-fly transitions between similar mechanisms are not promoted by today’s Internet construction principles. In light of the considerations above, the present whitepaper advocates mechanism transitions as a fundamental new principle for the Internet and makes inroads into its modeling and specification. The quest for a fundamentally more flexible Internet is not only fueled by trends regarding users and applications ‘above’, but also by innovations in the network technology ‘below’: Software-defined systems and networks emerge as an enabling technology for more flexibility, but cannot be sufficiently leveraged for more flexibility in the Internet as a whole. The German Collaborative Research Center MAKI investigates appropriate models, concepts and methods as well as prerequisites and benefits in regard to mechanism transitions in the Future Internet. The present whitepaper comprises approaches to the modeling and specification of such mechanism transitions, both from a structural and a behavioral perspective, as developed over the last three years. The various other aspects of MAKI, such as investigations of particular sets of mechanism or monitoring and control aspects, are not covered here. The whitepaper starts by providing a more detailed discussion of the quest for Internet mechanism transitions and of related issues. It continues by introducing the basic MAKI architecture and terminology in comparison to those of the OSI standard and the Internet. In the sequel, different approaches to the general structural and behavioral modeling and specification of mechanism transitions are presented, as developed and used in MAKI. The presented research contributions were created with different purposes and focuses in mind; they represent important steps forward on our path towards a consolidated framework for mechanism transitions. In other words, they make inroads into a highly dynamic Future Internet that can cope with ever increasing dynamics. We will use terminology from the ISO OSI standard as a starting point for introducing our terms and concepts. For readers with limited knowledge in this underlying standard, we provide a short OSI terminology primer in the appendix.