The current Internet architecture was founded upon a host-centric communication model, which was appropriate for coping with the needs of the early Internet users. Internet usage has evolved however, with most users mainly interested in accessing (vast amounts of) information, irrespective of its physical location. This paradigm shift in the usage model of the Internet, along with the pressing needs for, among others, better security and mobility support, has led researchers into considering a radical change to the Internet architecture. In this direction, we have witnessed many research efforts investigating Information-Centric Networking (ICN) as a foundation upon which the Future Internet can be built. Our main aims in this survey are: (a) to identify the core functionalities of ICN architectures, (b) to describe the key ICN proposals in a tutorial manner, highlighting the similarities and differences among them with respect to those core functionalities, and (c) to identify the key weaknesses of ICN proposals and to outline the main unresolved research challenges in this area of networking research.

Cognitive radio (CR) has emerged as a promising technology to exploit the unused portions of spectrum in an opportunistic manner. The fixed spectrum allocation of governmental agencies results in unused portions of spectrum, which are called "spectrum holes" or "white spaces". CR technology overcomes this issue, allowing devices to sense the spectrum for unused portions and use the most suitable ones, according to some pre-defined criteria. Spectrum assignment is a key mechanism that limits the interference between CR devices and licensed users, enabling a more efficient usage of the wireless spectrum. Interference is a key factor that limits the performance in wireless networks. The scope of this work is to give an overview of the problem of spectrum assignment in cognitive radio networks, presenting the state-of-the-art proposals that have appeared in the literature, analyzing the criteria for selecting the most suitable portion of the spectrum and showing the most common approaches and techniques used to solve the spectrum assignment problem. Finally, an analysis of the techniques and approaches is presented, discussing also the open issues for future research in this area.

The Internet is straining to meet demands that its design never anticipated, such as supporting billions of mobile devices and transporting huge amounts of multimedia content. The publish-subscribe Internet (PSI) architecture, a clean slate information-centric networking approach to the future Internet, was designed to satisfy the current and emerging user demands for pervasive content delivery, which the Internet can no longer handle. This article provides an overview of the PSI architecture, explaining its operation from bootstrapping to information delivery, focusing on its support for network layer caching and seamless mobility, which make PSI an excellent platform for ubiquitous information delivery.

While blockchains and more generally Distributed Ledger Technologies (DLTs) are passing over their hype curve peak, their shortcomings are becoming more apparent. One relatively recent approach to address their performance, scalability, privacy and other problems is to use multiple different DLTs instead of relying on just one. While there are no really established standards for combining several DLTs, a few repeating patterns can be observed. In this paper, we present a survey of interledger approaches, discussing and comparing their underlying mechanisms. A shared motivation for all of the discussed interledger solutions is to move away from the “one chain rules them all” model to one that allows the interconnection of multiple ledgers, with different features and advantages, while also supporting innovation. The interledger approaches discussed in this survey include (i) atomic cross-chain transactions, (ii) transactions across a network of payment channels, (iii) the W3C Interledger Protocol (ILP), (iv) bridging, (v) sidechains, and (vi) ledger-of-ledgers. The approaches are compared according to whether they support the transfer or the exchange of value, their interconnection trust mechanism, complexity, scalability, and transaction cost.