Abstract: The Internet was conceived nearly 40 years ago, by a small number of creative and forward-looking people. It started with the simple idea to enable direct communication between computers via a simple network protocol – later dubbed the Internet Protocol (IP). It started with a simple configuration – only four nodes – and the subsequent success story is wellknown. Driven by several factors – the immense advances in microelectronics, computer and software technology and innovative, disruptive business models – today the Internet consists of millions of interconnected subnetworks and more than a billion private and business users and devices all over the globe using a huge variety of services. The average traffic over the Internet adds up to some exabytes (1018 byte) per day. The growth with respect to users and traffic is continuing exponentially, especially since the mobile data communication is gaining momentum, but also because realtime applications like telephony and streaming services have been introduced and are becoming popular. Even more application areas are evolving, like Internet TV or sensorbased systems. So why are we talking now about a “Next Generation Internet” or “Future Internet”? Are there any deficits and problems which can hamper the further usage and expansion of the Internet? The answer is: yes. From today’s perspective, the IP technology is about to take over all traditional communication networks: the telephone, the data networks, the mobile/wireless and even the broadcast networks. It has evolved into a “critical infrastructure”. This already poses severe problems today and entails big challenges for the future. The Internet and its protocol stack were definitely not built for • high-quality realtime communication, • support of network-wide mobility, • wireless devices, • extreme scalability (billions of devices), • very high bit rates (Gbit/s and Tbit/s), • high resilience and carrier-grade networks, • provisioning security against professional attackers, • community applications, file sharing, gaming and other mass applications, • eCommerce including accounting and billing, and • cost-effective network operation and service to name only the most obvious issues.