The Internet has become in three decades, the main foundation of the information era. During this short time, it has gone through two heavy mutations. First, it has gone through a size mutation : from a dozen of connected systems, it has grown to a huge size of more than 285 million hosts. Second it has gone through a form mutation : from mainframes connected by phone lines, it has mutated to wireless-enabled laptops and gigabit routers connected by fiber optics. These mutations are bringing two great challenges to the Internet researchers. First we have to map the Internet topology with accuracy and timeliness in order to improve the efficiency of the forthcoming protocols. Second we have to develop new protocols for providing advanced communication functionalities such as mobility, security and multicast that are adapted to the new devices and usages of the Internet. To this end, we present here contributions that resolve some parts of the challenges described earlier. These are focused on Internet mapping, multicast state storing, host level networking and overlay design.
