In distributed consensus systems (DCSs), a single peer exposes functionality to other peers to agree on a shared state for a computational problem, such as for cryptocurrencies and distributed file systems. We observe, however, that this original, peer-centric model has evolved towards deploying several peers at a single network location, thus exposing the same DCS services many times, driven by the fees and rewards that can be gained by doing so. We refer to this trend as the service-centric model and provide in our paper evidence for this trend, its growth, and its impact on DCS operations, using empirical observations in the Ethereum system. Specifically, we shed light on the opposing observations of increasing reliance on highly available cloud infrastructures and large numbers of non-reachability events in the DCS. We provide recommendations on how to tackle this impact through changes to the Ethereum platform and identifier generation, believing that those recommendations and our empirical observations provide useful insights for building resilient and bias-free DePIN platforms.

The possibility of richer computing capabilities within Internet network elements, often captured as Computing in the Network (COIN), promises performance and flexibility gains to the wider Internet, akin to those seen in recent data center advances. At the same time, moving computation into the network is seemingly at odds with the fundamental end-to-end principle underlying the development of key technologies in the Internet. In this paper, we do not only argue that the latter is not the case, but we also shed light on what ‘in the network’ may or may not entail, aiming to sharpen a possible research agenda for COIN. Taking the transport layer as an example due to its typical end-to-end realization in and importance for today's Internet, we outline key design considerations for evolving towards a COIN-enabled transport capability. By further creating linkages to existing efforts and concepts, we provide possible future directions for the design of protocols for the future Internet.

Access to networks for purposes of executing remote services has become a dominant form of communication, while virtualization has enabled the flexible and fast deployment of those services across distributed locations. This seems at odds with the design that drives the network layer of the Internet. Our paper presents an approach to flexibly deploy a network layer solution for optimizing service access within a single domain, while retaining full connectivity to Internet-based services. We discuss design considerations and the resulting design. We analyze expected gains from our solution.

Efficient mobility management techniques are critical in providing seamless connectivity and session continuity between a mobile node and the network during its movement. However, current mobility management solutions generally require a central entity in the network core, tracking IP address movement, and anchoring traffic from source to destination through point-to-point tunnels. Intuitively, this approach suffers from scalability limitations as it creates bottlenecks in the network, due to sub-optimal routing via the anchor point. This is often termed “dog-leg” routing. Meanwhile, alternative anchorless, solutions are not feasible due to the current limitations of the IP semantics, which strongly tie addressing information to location. In contrast, this paper introduces a novel anchorless mobility solution that overcomes these limitations by exploiting a new path-based forwarding fabric together with emerging mechanisms from information-centric networking. These mechanisms decouple the end-system IP address from the path based data forwarding to eliminate the need for anchoring traffic through the network core; thereby, allowing flexible path calculation and service provisioning. Furthermore, by eliminating the limitation of routing via the anchor point, our approach reduces the network cost compared to anchored solutions through bandwidth saving while maintaining comparable handover delay. The proposed solution is applicable to both cellular and large-scale wireless LAN networks that aim to support seamless handover in a single operator domain scenario. The solution is modeled as a Markov-chain which applies a topological basis to describe mobility. The validity of the proposed Markovian model was verified through simulation of both random walk mobility on random geometric networks and trace information from a large-scale, city wide data set. Evaluation results illustrate a significant reduction in the total network traffic cost by 45 percent or more when using the proposed solution, compared to Proxy Mobile IPv6.

Seamless connectivity plays a key role in realizing QoS-based delivery in mobile networks. However, current handover mechanisms hinder the ability to meet this target, due to the high ratio of handover failures, packet loss and service interruption. These challenges are further magnified in Heterogeneous Cellular Networks (HCN) such as Advanced Long Term Evolution (LTE-Advanced) and LTE in unlicensed spectrum (LTE-LAA), due to the variation in handover requirements. Although mechanisms, such as Fast Handover for Proxy Mobile IPv6 (PFMIPv6), attempt to tackle these issues; they come at a high cost with sub-optimal outcomes. This primarily stems from various limitations of existing IP core networks. In this paper we propose a novel handover solution for mobile networks, exploiting the advantages of a revolutionary IP over Information-Centric Networking (IP-over-ICN) architecture in supporting flexible service provisioning through anycast and multicast, combined with the advantages of random linear coding techniques in eliminating the need for retransmissions. Our solution allows coded traffic to be disseminated in a multicast fashion during handover phase from source directly to the destination(s), without the need for an intermediate anchor as in exiting solutions; thereby, overcoming packet loss and handover failures, while reducing overall delivery cost. We evaluate our approach with an analytical and simulation model showing significant cost reduction compared to PFMIPv6.

Multicast data delivery can significantly reduce traffic in operators' networks, but has been limited in deployment due to concerns such as the scalability of state management. This paper shows how multicast can be implemented in contemporary software defined networking (SDN) switches, with less state than existing unicast switching strategies, by utilising a Bloom Filter (BF) based switching technique. Furthermore, the proposed mechanism uses only proactive rule insertion, and thus, is not limited by congestion or delay incurred by reactive controller-aided rule insertion. We compare our solution against common switching mechanisms such as layer-2 switching and MPLS in realistic network topologies by modelling the TCAM state sizes in SDN switches. The results demonstrate that our approach has significantly smaller state size compared to existing mechanisms and thus is a multicast switching solution for next generation networks.

Large-scale information dissemination in multicast communications has been increasingly attracting attention, be it through uptake in new services or through recent research efforts. In these, the core issues are supporting increased forwarding speed, avoiding state in the forwarding elements, and scaling in terms of the multicast tree size. This paper addresses all these challenges-which are crucial for any scalable multicast scheme to be successful-by revisiting the idea of in-packet Bloom filters and source routing. As opposed to the traditional in-packet Bloom filter concept, we build our Bloom filter by enclosing limited information about the structure of the tree. Analytical investigation is conducted and approximation formulas are provided for optimal-length Bloom filters, in which we got rid of typical Bloom filter illnesses such as false-positive forwarding. These filters can be used in several multicast implementations, which are demonstrated through a prototype. Thorough simulations are conducted to demonstrate the scalability of the proposed Bloom filters compared to its counterparts.

No abstract available.

ABSTRACT Revealing one's interests in communication has been recognized as a growing problem in the Internet. We postulate that it is desirable for future information retrieval systems to provide privacy in both what information is requested and what information is received, without raising obstacles to the deployment of accounting and access control mechanisms. This paper outlines a solution that fulfills this requirement in the context of broker‐based systems, that is, systems in which brokers facilitate the communication between a consumer and a provider (of information). Broker‐assisted communication is a common paradigm used in many settings, including contemporary information‐centric networking approaches. We present the design and the evaluation of a solution that conceals consumers' interests, without hiding consumer identity or location. The developed solution is applied over a system of hierarchically organized brokers; similar systems are used in many information lookup services. Because in these systems, information is distributed in various locations, traditional private information retrieval (PIR) protocols exhibit significant communication overhead. Our solution achieves up to 97% less communication overhead compared with a PIR protocol, without additional computational overhead. Copyright © 2013 John Wiley & Sons, Ltd.

Information-centric networking (ICN)1is a new communication paradigm, which has been increasingly attracting attention in the wider research community. Its focus on information provides an alternative to the endpoint-centric model of today's Internet. While architectural foundations for ICN have been laid out in many ongoing efforts, solutions to forwarding information in such new networking environment still remain a challenge. Our criteria for a solution to this challenge are efficiency in terms of achievable link speed and scalability in terms of supported sizes of the network, while supporting multicast as a native operation. Our solution in this paper provides scalability through an extensible addressing format while keeping the forwarding operation efficient in terms of required state as well as forwarding performance.

Large-scale information distribution has been increasingly attracting attention, be it through uptake in new services or through recent research efforts in fields like information-centric networking. The core issue to be addressed is the more efficient distribution of information to a large set of receivers. Avoiding state in the forwarding elements is crucial for any scheme to be successful. This paper addresses this challenge by revisiting the idea of in-packet Bloom filters and source routing. As opposed to the traditional in-packet Bloom filter concept which represent the trees flatly as sets, we build our filter by enclosing limited information about the structure of the tree, namely its stage decomposition, which helps to get rid of typical Bloom filter illnesses as infinite loops and false positive forwarding. Our analytical and simulation results show that by using this information we obtain more succinct tree representation while still maintaining forwarding efficiency.

Various approaches to the configuration and control of intelligent environments have been researched in the past. The majority of these however, make use of either exclusively autonomous or exclusively end-user driven techniques which, in certain situations, may be an issue. A number of users may be reluctant to allow an autonomous system to monitor and interpret every action they take while, on the other hand, some users may be unable or unwilling to program and configure such a complex (end-user driven) system alone. This work-in-progress paper outlines our preliminary work aimed at exploring a solution to this issue by investigating the possibility of creating a hybrid autonomous-agent/end-user driven system that enables the user to set the level of autonomy for any given part of an intelligent environment. The principle contributions of this paper are to expose the issues regarding intelligent environment management systems, to give a comprehensive review of related work on adjustable autonomy and to present a conceptual model and an autonomy metric that can be used as a foundation of future research into developing hybrid autonomous-agent/end-user driven systems. This work forms part of an ongoing three year research project, funded by BT, that seeks to understand and address user concerns with the aim of equipping intelligent environments with better management systems and, furthermore, making intelligent environments more commercially deployable. Given the ongoing nature of this work, we propose to report any significant progress of this research at subsequent IE conferences until this work is complete.

With more than two billion phone subscribers worldwide and even more sold mobile phones, we can say that mobile phones are the most pervasive portable device today. Over the years their functionalities developed rapidly and today they can be used for performing tasks beyond just calling and messaging: they can provide an increasingly available intelligence at the edge of the network. This intelligence provides a fertile ground for the devices to act as sensor sinks in localized sensor networks and, furthermore, bridge between widely dispersed sensor networks through wide area connectivity. Currently, there are many sensor networks that have been deployed all over the world for various purposes. It is only natural that mobile phones would start, more and more, connecting to this available sensor infrastructure in order to use the data for customizing applications and services or collect, aggregate and provide the data to application servers. This paper presents a platform solution that allows for exploiting this very intelligence residing in everyone's mobile device to implement, among others, participatory sensing scenarios of various kinds. The platform is available under an open source license to facilitate innovation while preserving openness of key components of the platform.

Discovery of available and suitable services is an essential piece within a service provisioning architecture. Numerous approaches have been proposed, standardized and deployed in the past. However, many of them either lack deployment (i.e., adoption beyond certain research labs or communities) or features (in particular in the area of visiting domain support, availability notifications, and disclosure authorization). The session initiation protocol (SIP) and its event delivery extensions promise a wide adoption in the Internet due to its fundamental importance for future session-based communication. Further, its adoption in the next generation of mobile devices will lay ground for a large-scale deployment of this protocol. This paper discusses the suitability of SIP events for service discovery by presenting a solution that provides many of the currently unsupported features. Deployments are proposed that would enable endpoint-based but also repository-based discovery, the latter aiming at integrating legacy systems into the solution.

The proliferation of smartphones throughout the past few years has provided an increasingly ubiquitous platform for intelligent services at the edge of the network. This paper presents an approach to use this intelligence for implementing an architecture that enables remote sensing scenarios in which we rely on intelligence residing in "sensing gateways" that perform the actual sensing but also required aggregation functionality of sensed information. For that, we will introduce a scenario for such remote sensing to motivate our approach. Further, the architecture and current prototype is presented.

With the growing popularity of the mobile Internet, end users would demand seamless continuation of their Internet applications as they hop across different access technologies and administrative domains during an ongoing session. An important technology to enable this is mobile IP and its companion seamless handoff protocols, which are currently under development in the IETF. These protocols can potentially provide the mobile end user with a seamless IP connectivity. However, additional techniques may be required to ensure seamless continuation of the user's Internet applications after an IP-level handoff. In this paper, we focus on the handoff scenario in which there is a need to relocate (or provision) certain application-specific functionality to ensure the seamless continuation of the user's application after handoff. We provide a solution framework called the application context transfer (ACT) framework to address this need and describe its application to such handoff scenarios.

Tailoring services and applications to the user's needs and environment is becoming an important feature to support in future mobile services. New techniques and functionalities need to be deployed to enable such features. Recently, multimedia messaging is evolving to be a major service to be supported in wireless networks. However today, multimedia messages are limitedly adapted in their delivery with respect to the user preferences and the current context the user is in, including the access network the user is currently using. In this paper, we outline scenarios that motivate the need for more sophisticated adaptation means that is particularly suit heterogeneous access scenarios. We propose an architecture and the specific information to be used in order to enable tailored delivery of multimedia messages.

Distributed conferencing applications have become more and more popular. Progress in communication systems and increased functionality of these applications are the main pushing factors from a technical point of view. The increasing costs and distribution of institutions are the pulling factors from a user's point of view. Key features of group communication applications are conference management, multipoint communication, distributed application synchronization, and user data marshaling. These features are mostly independent from specific scenarios. Thus, it is useful to provide a generic service to accelerate and simplify the development of such applications. For global usage in the Internet, scalability in terms of group size and distribution of the entities is a big issue in the design of such services. The paper defines requirements for a scalable conferencing service introducing the services as well as the protocol mechanisms. Finally, the implementation design of the service is presented.

An efficient conference service facilitates the implementation and the run-time control of conference applications. Key features of a conference service are conference management, multicast communication support, application state synchronization, user data marshalling and scalability. The paper defines a conferencing service to fulfil these requirements of conferencing applications. The conference control protocol, which is used for our conferencing service, is described in its main parts like topology, reconfiguration and multipoint transfer. An object model of the service is proposed together with the resulting architecture. A multipoint platform is introduced as a case study.