Over the past decade, online social networks (OSNs) such as Twitter and Facebook have thrived and experienced rapid growth to over 1 billion users. A major evolution would be to leverage the characteristics of OSNs to evaluate the effectiveness of the many routing schemes developed by the research community in real-world scenarios. In this paper, we showcase the Secure Opportunistic Schemes (SOS) middleware which allows different routing schemes to be easily implemented relieving the burden of security and connection establishment. The feasibility of creating a delay tolerant social network is demonstrated by using SOS to power AlleyOop Social, a secure delay tolerant networking research platform that serves as a real-life mobile social networking application for iOS devices. SOS and AlleyOop Social allow users to interact, publish messages, and discover others that share common interests in an intermittent network using Bluetooth, peer-to-peer WiFi, and infrastructure WiFi.
In recent years, a number of social-aware and social-based routing schemes have leveraged social interactions to deliver data using delay tolerant networks (DTNs) @cite_0 . However, related work has primarily evaluated routing protocols in simulation environments, which provide valuable analyses, but are based on synthetic mobility patterns to emulate node movement and tend to use abstract models to imitate the radio response of real commodity wireless technologies @cite_6 @cite_26 @cite_5 . There are a few studies that have taken on the approach of demonstrating DTNs in realistic environments @cite_22 @cite_25 @cite_14 . However, these studies do not consider other significant aspects, such as user security and privacy along with the limitation of operating with only the epidemic routing scheme. Various middlewares @cite_2 @cite_19 @cite_7 @cite_17 , testbeds @cite_13 @cite_21 @cite_9 @cite_15 @cite_8 @cite_12 @cite_20 @cite_1 , and mobile applications have been developed to address providing deployable delay tolerant networking applications which can operate with minimal infrastructure and effectively evaluate DTN routing protocols.
@cite_22 @cite_2 @cite_5 @cite_15 @cite_20 @cite_8 @cite_21 @cite_17 @cite_26 @cite_7 @cite_6 @cite_19 @cite_25 @cite_12 @cite_14 @cite_9 @cite_1 @cite_0 @cite_13
2017478515 2078129565 2147830904 2155528675
In the past few years, more and more researchers have paid close attention to the emerging field of delay tolerant networks (DTNs), in which network often partitions and end-to-end paths do not exist nearly all the time. To cope with these challenges, most routing protocols employ the "store-carry-forward" strategy to transmit messages. However, the difficulty of this strategy is how to choose the best relay node and determine the best time to forward messages. Fortunately, social relations among nodes can be used to address these problems. In this paper, we present a comprehensive survey of recent social-aware routing protocols, which offer an insight into how to utilize social relationships to design efficient and applicable routing algorithms in DTNs. First, we review the major practical applications of DTNs. Then, we focus on understanding social ties between nodes and investigating some design-related issues of social-based routing approaches, e.g., the ways to obtain social relations among nodes, the metrics and approaches to identify the characteristics of social ties, the strategies to optimize social-aware routing protocols, and the suitable mobility traces to evaluate these protocols. We also create a taxonomy for social-aware routing protocols according to the sources of social relations. Finally, we outline several open issues and research challenges. Delay-tolerant network architectures exploit mobile devices carried by users to enable new networked applications. Efficiently routing information through these DTNs faces new challenges such as mobility and the dynamic nature of the network. Previous work has looked at using encountered nodes to build a social network for routing. In this work we construct routing tables from users' self-reported social networks. Initial experiments indicate that this significantly reduces the delivery cost of transmitting messages through a DTN. Delay-tolerant networks (DTNs) have the potential to connect devices and areas of the world that are under-served by current networks. A critical challenge for DTNs is determining routes through the network without ever having an end-to-end connection, or even knowing which "routers" will be connected at any given time. Prior approaches have focused either on epidemic message replication or on knowledge of the connectivity schedule. The epidemic approach of replicating messages to all nodes is expensive and does not appear to scale well with increasing load. It can, however, operate without any prior network configuration. The alternatives, by requiring a priori connectivity knowledge, appear infeasible for a self-configuring network.In this paper we present a practical routing protocol that only uses observed information about the network. We designed a metric that estimates how long a message will have to wait before it can be transferred to the next hop. The topology is distributed using a link-state routing protocol, where the link-state packets are "flooded" using epidemic routing. The routing is recomputed when connections are established. Messages are exchanged if the topology suggests that a connected node is "closer" than the current node.We demonstrate through simulation that our protocol provides performance similar to that of schemes that have global knowledge of the network topology, yet without requiring that knowledge. Further, it requires a significantly smaller quantity of buffer, suggesting that our approach will scale with the number of messages in the network, where replication approaches may not. The routing performance of delay tolerant networks (DTN) is highly correlated with the distribution of inter-contact times (ICT), the time period between two successive contacts of the same two mobile nodes. As humans are often carriers of mobile communication devices, studying the patterns of human mobility is an essential tool to understand the performance of DTN protocols. From measurement studies of human contact behaviors, we find that their distributions closely resemble a form of power-law distributions called truncated Pareto. Human walk traces has a dichotomy distribution pattern of ICT; it has a power-law tendency up to some time, and decays exponentially after that time. Truncated Pareto distributions offer a simple yet cohesive mathematical model to express this dichotomy in the measured data. Using the residual and relaxation time theory [17] [4], we apply truncated Pareto distributions to quantify the performance of opportunistic routing in DTN. We further show that Truncated Levy walk (TLW) mobility model [22] commonly used in biology to describe the foraging patterns of animals [25], provide the same truncated power-law ICT distributions as observed from the empirical data, especially when mobility is confined within a finite area. This result confirms our recent finding that human walks contain similar statistical characteristics as Levy walks [22].