The end-to-end nature of today’s application and transport protocols is increasingly being questioned by the growing heterogeneity of networks and devices, and the emergence of rich in-network services. As a result, performance of end-to-end protocols is often poor and many in-network optimizations are hard to deploy because they do not ﬁt into today’s Internet architecture. This thesis takes a clean slate approach towards better accommodating diversity in the Internet architecture. We propose two architectural concepts: i) today’s end-to-end transport is unbundled such that network speciﬁc functions, like congestion control, are implemented on a per-segment basis, where a segment spans a part of the end-to-end path that can be considered homogeneous (e.g., wired Internet or an access network) and ii) we expose applications’ data units and their naming to certain elements within the network, thereby facilitating the deployment of various data oriented and higher level services inside the network. We have designed a network architecture, Tapa, that systematically combines these concepts into a coherent architecture. Tapa uses end-to-end protocols that transfer application data units (ADU) over segments; these segments appear as traditional Internet-like “links” to the end-to-end protocols and can use Internet-style protocols (e.g., TCP/IP-like protocols in the backbone) or custom solutions at the edges. We demonstrate the eﬀectiveness of Tapa by showing how it can support: i) various wireless and mobility optimizations, ii) an in-network energy saving service that can provide up to 2-5x improvement in battery life of mobile devices, iii) improved content distribution in online social networks, and iv) higher level services with new application semantics.