Content-centric networking (CCN) introduces a paradigm shift from a host centric to an information centric communication model for future Internet architectures. It supports the retrieval of a particular content regardless of the physical location of the content. Content caching and content delivery networks are the most popular approaches to deal with the inherent issues of content delivery on the Internet that are caused by its design. Moreover, intermittently connected mobile environments or disruptive networks present a significant challenge to CCN deployment. In this paper, we consider the possibility of using mobile users in improving the efficiency of content delivery. Mobile users are producing a significant fraction of the total Internet traffic, and modern mobile devices have enough storage to cache the downloaded content that may interest other mobile users for a short period too. We present an analytical model of the CCN framework that integrates a delay tolerant networking architecture into the native CCN, and we present large-scale simulation results. Caching on mobile devices can improve the content retrieval time by more than 50 , while the fraction of the requests that are delivered from other mobile devices can be more than 75 in many cases.
From a social-based point of view, the authors of SocialCast @cite_34 proposed a routing framework that exploits the social ties among users for effective relay selection, while in @cite_29 discussed the design of a publish-subscribe communication overlay based on the distributed detection of social groups by means of centrality measures. However, this routing mechanisms can be complementary to our proposed scheme, which operates independently of any routing algorithm. Lu at @cite_25 used the K-means clustering algorithm to build the social level forwarding scheme in order to reduce the transmitted messages. This approach raises several inevitable limitations: the interest may fail to reach the encountered node with the same social level that might have the content to satisfy the interest, the request from the higher social level will never reach a content provider with a lower social level, the proposed scheme cannot detect the routing loop of the packet and the authors have not considered how to optimise similar interests from multiple users. These limitations are addressed in our solution.
@cite_29 @cite_34 @cite_25
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Applications involving the dissemination of information directly relevant to humans (e.g., service advertising, news spreading, environmental alerts) often rely on publish-subscribe, in which the network delivers a published message only to the nodes whose subscribed interests match it. In principle, publish- subscribe is particularly useful in mobile environments, since it minimizes the coupling among communication parties. However, to the best of our knowledge, none of the (few) works that tackled publish-subscribe in mobile environments has yet addressed intermittently-connected human networks. Socially-related people tend to be co-located quite regularly. This characteristic can be exploited to drive forwarding decisions in the interest-based routing layer supporting the publish-subscribe network, yielding not only improved performance but also the ability to overcome high rates of mobility and long-lasting disconnections. In this paper we propose SocialCast, a routing framework for publish-subscribe that exploits predictions based on metrics of social interaction (e.g., patterns of movements among communities) to identify the best information carriers. We highlight the principles underlying our protocol, illustrate its operation, and evaluate its performance using a mobility model based on a social network validated with real human mobility traces. The evaluation shows that prediction of colocation and node mobility allow for maintaining a very high and steady event delivery with low overhead and latency, despite the variation in density, number of replicas per message or speed. Many message delivery services are based on publish-subscribe systems designed to distribute updates through centralized infrastructures requiring active Internet connections. For mobile devices, individual nodes should have the ability to propagate messages to interested users over ad-hoc wireless connections thereby removing the dependence on Internet and centralized servers. These nodes are sometimes stationary, but are often mobile, creating intermittent networks of nodes that tend to be socially related. In this paper, we propose LESC, a delay-tolerant message delivery protocol, which facilitates efficient message dissemination in a decentralized, ad-hoc fashion and can be implemented using a commodity mobile communication technology such as Bluetooth LE. By leveraging the frequent collocation of socially related peers, nodes strategically become information carriers with the ability to propagate messages to out of range nodes in the future. We design a discrete event simulator that utilizes actual traveling paths derived from Google Maps. The simulator emulates LESC and the epidemic routing protocol to determine if we can achieve reasonable performance. Related works have approached the problem of publish-subscribe systems on mobile devices, but to the best of our knowledge, have not shown the feasibility of a protocol that can directly be implemented over current commodity wireless technologies. We simulate the protocol in Matlab and allow nodes to have multiple publications and subscriptions simultaneously. The problem of simultaneously disseminating k messages in a large network of n nodes, in a decentralized and distributed manner, where nodes only have knowledge about their own contents, is studied. In every discrete time-step, each node selects a communication partner randomly, uniformly among all nodes and only one message can be transmitted. The goal is to disseminate rapidly, with high probability, all messages to all nodes. It is shown that a random linear coding (RLC) based protocol disseminates all messages to all nodes in time ck+ spl Oscr ( spl radic kln(k)ln(n)), where c<3.46 using pull-based dissemination and c<5.96 using push-based dissemination. Simulations suggest that c<2 might be a tighter bound. Thus, if k spl Gt (ln(n)) sup 3 , the time for simultaneous dissemination RLC is asymptotically at most ck, versus the spl Omega (klog sub 2 (n)) time of sequential dissemination. Furthermore, when k spl Gt (ln(n)) sup 3 , the dissemination time is order optimal. When k spl Lt (ln(n)) sup 2 , RLC reduces dissemination time by a factor of spl Omega ( spl radic k lnk) over sequential dissemination. The overhead of the RLC protocol is negligible for messages of reasonable size. A store-and-forward mechanism without coding is also considered. It is shown that this approach performs no better than a sequential approach when k= spl prop n. Owing to the distributed nature of the system, the proof requires analysis of an appropriate time-varying Bernoulli process. Most currently proposed solutions to application-level multicast organise the group members into an application-level mesh over which a Distance-Vector routing protocol, or a similar algorithm, is used to construct source-rooted distribution trees. The use of a global routing protocol limits the scalability of these systems. Other proposed solutions that scale to larger numbers of receivers do so by restricting the multicast service model to be single-sourced. In this paper, we propose an application-level multicast scheme capable of scaling to large group sizes without restricting the service model to a single source. Our scheme builds on recent work on Content-Addressable Networks (CANs). Extending the CAN framework to support multicast comes at trivial additional cost and, because of the structured nature of CAN topologies, obviates the need for a multicast routingalg orithm. Given the deployment of a distributed infrastructure such as a CAN, we believe our CAN-based multicast scheme offers the dual advantages of simplicity and scalability.