At the time the Internet was designed, end systems were stationary and interconnected through permanent, wired links. Support for highly mobile hosts that frequently switch access technologies was not a design objective. However, nomadic and mobile hosts will dominate the market and there is high demand for ubiquitous connectivity. Still, in the foreseeable future, the goal of providing "always connected" network access for mobile users will not be met, as wireless links are always subject to limitations: in geographical coverage, due to interference, and obstacles on the radio link, but also for economic reasons.The Challenged Internet Access Network Technology Infrastructure (CHIANTI) project will improve disconnection and disruption tolerance for mobile user communications relying on the unmodified core Internet architecture. This is achieved by deploying a new service-support infrastructure - operated by a third-party as an overlay or closely integrated with an operator network - that complements the core IP and mobility functionality to sustain operation and performance of business and consumer applications: Remote file access and email, interactive web access, end even real-time media streaming maintain a satisfying user experience and full business productivity even under intermittent connectivity.In the highly dynamic environments experienced by mobile users, a communications service should utilize available link-layer access technologies according to configurable criteria such as bandwidth, latency, and - often neglected - cost. It is a key goal for the CHIANTI architecture to co-exist with and benefit from the presence of existing and emerging "always best connected" solutions. Based on a cross-layer approach, transport and session protocols, performance enhancements, and application-specific functions are addressed by a small and effective consortium of leading research institutions and SMEs with considerable experience in the field.