Rhythm and Randomness in Human Contact

There is substantial interest in the effect of human mobility patterns on opportunistic communications. Inspired by recent work revisiting some of the early evidence for a L\'evy flight foraging strategy in animals, we analyse datasets on human contact from real world traces. By analysing the distribution of inter-contact times on different time scales and using different graphical forms, we find not only the highly skewed distributions of waiting times highlighted in previous studies but also clear circadian rhythm. The relative visibility of these two components depends strongly on which graphical form is adopted and the range of time scales. We use a simple model to reconstruct the observed behaviour and discuss the implications of this for forwarding efficiency

Selfishness, altruism and message spreading in mobile social networks

Many kinds of communication networks, in particular social and opportunistic networks, rely at least partly on on humans to help move data across the network. Human altruistic behavior is an important factor determining the feasibility of such a system. In this paper, we study the impact of different distributions of altruism on the throughput and delay of mobile social communication system. We evaluate the system performance using four experimental human mobility traces with uniform and community-biased traffic patterns. We found that mobile social networks are very robust to the distributions of altruism due to the nature of multiple paths. We further confirm the results by simulations on two popular social network models. To the best of our knowledge, this is the first complete study of the impact of altruism on mobile social networks, including the impact of topologies and traffic patterns.published_or_final_versio

An architectural framework for heterogeneous networking.

The growth over the last decade in the use of wireless networking devices has been explosive. Soon many devices will have multiple network interfaces, each with very different characteristics. We believe that a framework that encapsulates the key challenges of heterogeneous networking is required. Like a map clearly helps one to plan a journey, a framework is needed to help us move forward in this unexplored area. The approach taken here is similar to the OSImodel in which tightly defined layers are used to specify functionality, allowing a modular approach to the extension of systems and the interchange of their components, whilst providing a model that is more oriented to heterogeneity and mobility

FLICK: developing and running application-specific network services

Data centre networks are increasingly programmable, with application-specific network services proliferating, from custom load-balancers to middleboxes providing caching and aggregation. Developers must currently implement these services using traditional low-level APIs, which neither support natural operations on application data nor provide efficient performance isolation. We describe FLICK, a framework for the programming and execution of application-specific network services on multi-core CPUs. Developers write network services in the FLICK language, which offers high-level processing constructs and application-relevant data types. FLICK programs are translated automatically to efficient, parallel task graphs, implemented in C++ on top of a user-space TCP stack. Task graphs have bounded resource usage at runtime, which means that the graphs of multiple services can execute concurrently without interference using cooperative scheduling. We evaluate FLICK with several services (an HTTP load-balancer, a Memcached router and a Hadoop data aggregator), showing that it achieves good performance while reducing development effort

Exploiting contextual handover information for versatile services in NGN environments.

Users in ubiquitous and pervasive computing environments will be much more empowered in ways to access and to control their navigation. Handover, the vital event in which a user changes the attachment point in a Next Generation Network (NGN), is an important occasion and the conditions and environment in which it is executed can offer relevant information for businesses. This paper describes the capabilities of a platform which intends to exploit contextual handover information offering a rich environment that can be used by access and content providers for building innovative context-aware multi-provided services. Based on ontologies, the technique not only eases the building of versatile services but also provides a comprehensive source of information both for enriching user navigation in the network as well as for the improvement of the provider’s relationship with their customers

Towards real-time community detection in large networks

The recent boom of large-scale Online Social Networks (OSNs) both enables and necessitates the use of parallelisable and scalable computational techniques for their analysis. We examine the problem of real-time community detection and a recently proposed linear time - O(m) on a network with m edges - label propagation or "epidemic" community detection algorithm. We identify characteristics and drawbacks of the algorithm and extend it by incorporating different heuristics to facilitate reliable and multifunctional real-time community detection. With limited computational resources, we employ the algorithm on OSN data with 1 million nodes and about 58 million directed edges. Experiments and benchmarks reveal that the extended algorithm is not only faster but its community detection accuracy is compared favourably over popular modularity-gain optimization algorithms known to suffer from their resolution limits.Comment: 10 pages, 11 figure

Connecting the Edges: A Universal, Mobile-Centric, and Opportunistic Communications Architecture

The Internet has crossed new frontiers with access to it getting faster and cheaper. Considering that the architectural foundations of today's Internet were laid more than three decades ago, the Internet has done remarkably well until today coping with the growing demand. However, the future Internet architecture is expected to support not only the ever growing number of users and devices, but also a diverse set of new applications and services. Departing from the traditional host-centric access paradigm, where access to a desired content is mapped to its location, an information-centric model enables the association of access to a desired content with the content itself, irrespective of the location where it is being held. UMOBILE tailors the information-centric communication model to meet the requirements of opportunistic communications, integrating those connectivity approaches into a single architecture. By pushing services near the edge of the network, such an architecture can pervasively operate in any networking environment and allows for the development of innovative applications, providing access to data independent of the level of end-to-end connectivity availability

Low Power Optical Transceivers for Switched Interconnect Networks

The power-consumption of network equipment is under ever-increasing scrutiny. As part of an ensemble project seeking to reduce power-consumption within data-centers1, this work focuses on reducing the power consumption of photonic transceivers for future fast power gated and/or optical switching networks. Utilising an open-source toolkit, we show that Serializer/Deserializer (SERDES) dominates power consumption of traditional optical transceivers. This result has particular implications for the modulation format of future interconnects. At 25 Gb/s line rate, SERDES blocks of PAM-16 and 4-wavelength WDM are shown to have 53% and 79% lower power respectively compared with SERDES of serial NRZ as well as reduced power gating restoration time and energy