At the dawn of big data and 5G networks, end-to-end communication with large amounts of data between mobile devices is difficult to be implemented through the traditional face-to-face transmission mechanism in social networks. Consequently, opportunistic social networks proposed that message applications should choose proper relay nodes to perform effective data transmission processes. At present, several routing algorithms, based on node similarity, attempt to use the contextual information related to nodes and the special relationships between them to select a suitable relay node among neighbors. However, when evaluating the similarity degree between a pair of nodes, most existing algorithms in opportunistic social networks pay attention to only a few similar factors, and even ignore the importance of mobile similarity in the data transmission process. To improve the transmission environment, this study establishes a fuzzy routing-forwarding algorithm (FCNS) exploiting comprehensive node similarity (the mobile and social similarities) in opportunistic social networks. In our proposed scheme, the transmission preference of the node is determined through the fuzzy evaluation of mobile and social similarities. The suitable message delivery decision is made by collecting and comparing the transmission preference of nodes, and the sustainable and stable data transmission process is performed through the feedback mechanism. Through simulations and the comparison of social network algorithms, the delivery ratio in the proposed algorithm is 0.85 on average, and the routing delay and network overhead of this algorithm are always the lowest.

FCNS: A Fuzzy Routing-Forwarding Algorithm Exploiting Comprehensive Node Similarity in Opportunistic Social Networks

In opportunistic networks, the nature of intermittent and disruptive connections degrades the efficiency of routing. Epidemic routing protocol is used as a benchmark for most of routing protocols in opportunistic mobile social networks (OMSNs) due to its high message delivery and latency. However, Epidemic incurs high cost in terms of overhead and hop count. In this paper, we propose a hybrid routing protocol called EpSoc which utilizes the Epidemic routing forwarding strategy and exploits an important social feature, that is, degree centrality. Two techniques are used in EpSoc. Messages’ TTL is adjusted based on the degree centrality of nodes, and the message blocking mechanism is used to control replication. Simulation results show that EpSoc increases the delivery ratio and decreases the overhead ratio, the average latency, and the hop counts as compared to Epidemic and Bubble Rap.

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EpSoc: Social-Based Epidemic-Based Routing Protocol in Opportunistic Mobile Social Network

Opportunistic networks (OppNets) refer to a number of wireless nodes opportunistically communicating with each other in a form of “Store–Carry–Forward”. This occurs when they come into contact with each other without a proper network infrastructure. OppNets are designed to operate in an environment characterized by high delay, high error rate, intermittent connectivity, and non-availability of end-to-end route between the source and destination. OppNets use wireless technologies, such as IEEE 802.11, WiMAX, Bluetooth, and other short-range radio communication, and grow from a single node (seed) to become large networks by inviting new nodes (helpers) to join the network. Nodes have the ability to store and carry data and also forward it to other nodes in order to achieve different tasks. In OppNets, there is no end-to-end connection between the source and the destination nodes. Further, due to their inherent features, OppNets suffer from frequent partitions and long delays, while also being subjec...

Routing protocols in opportunistic networks – a survey

A taxonomy on misbehaving nodes in delay tolerant networks

In opportunistic networks (OppNets), routing and data forwarding among mobile devices are facilitated by relays or next-hop forwarders. To guarantee end-to-end data delivery it is important to provide participation. However, in sparsely connected OppNets, it is extremely challenging to monitor the behaviour of the relays and identify selfish/malicious relays cooperating with each other in order to forge routing information or drop useful data. Cooperation enforcement schemes are seen as a lightweight alternative to conventional secure forwarding techniques that involve cryptographically signed certificate exchanges, providing a ‘softer’ security layer to protect basic networking operations. In general, cooperation enforcement schemes fall into two broad categories: trust establishment via a reputation system and pricing or credit-based schemes. This study offers a comprehensive survey of representative cooperation enforcement schemes that exploit a reputation system. The authors analyse their distinct features, identify and discuss critical challenges that should be efficiently addressed when designing such mechanisms, indicating at the same time potential solutions and provide an informative table to display the authors’ findings. From this analysis, they examine issues and concerns surrounding the field of cooperation enforcement in OppNets, and provide guidelines and directions for future researchers.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-net.2017.0079

Towards an incentive-compatible, reputation-based framework for stimulating cooperation in opportunistic networks: a survey

Opportunistic networks or OppNets refer to a number of wireless nodes opportunistically communicating with each other in a form of “Store–Carry–Forward”. This occurs when they come into contact with each other without proper network infrastructure. OppNets use wireless technologies, such as IEEE 802.11, WiMAX, Bluetooth, and other short-range radio communication. In OppNets, there is no end-to-end connection between the source and the destination nodes, and the nodes usually have high mobility, low density, limited power, short radio range, and often subject to different kinds of attacks by malicious nodes. Due to these characteristics and features, OppNets are subject to serious security challenges. OppNets strongly depend on human interaction; therefore, the success of securing such networks is based on trust between people. This survey includes the security approaches in OppNets and techniques used to increase their security levels.

Security and Trust in Opportunistic Networks – A Survey

Defense against packet collusion attacks in opportunistic networks

Security is a major challenge in Opportunistic Networks (OppNets) due to its characteristics of being an open medium with dynamic topology, there is neither a centralized management nor clear lines of defence. A packet dropping attack is one of the major security threats in OppNets as neither source nodes nor destination nodes have any knowledge of when or where a packet will be dropped. In this paper, we present a novel attack and detection mechanism against a special type of packet dropping where the malicious node drops one packet or more and injects a new fake packet instead. Our novel detection mechanism is very powerful and has very high accuracy. It relies on a very simple yet powerful idea, the creation time of each packet. Significant results show this robust mechanism achieves a very high accuracy and detection rate.

Packet Faking Attack: A Novel Attack and Detection Mechanism in OppNets

Opportunistic networks (OppNets) are an interesting topic that are seen to have a promising future. Many protocols have been developed to accommodate the features of OppNets such as frequent partitions, long delays, and no end-to-end path between the source and destination nodes. Embedding security into these protocols is challenging and has taken a lot of attention in research. One of the attacks that OppNets are exposed to is the packet dropping attack, where the malicious node attempts to drop some packets and forwards an incomplete number of packets which results in the distortion of the message. To increase the security levels in OppNets, this paper presents an algorithm developed to detect packet dropping attacks, and finds the malicious node that attempted the attack. The algorithm detects the attack by using an indicative field in the header section of each packet; the indicative field has 3 sub fields - the identification field, the flag field, and the offset field. These 3 fields are used to find if a node receives the complete original number of packets from the previous node. The algorithm will have the advantage of detecting packets dropped by each intermediate node, this helps solve the difficulties of finding malicious nodes by the destination node only.

Asma'a Ahmad

Papers

Routing protocols in opportunistic networks – a survey

Security and Trust in Opportunistic Networks – A Survey

Defense against packet collusion attacks in opportunistic networks

Packet Faking Attack: A Novel Attack and Detection Mechanism in OppNets

Defense against packet dropping attacks in opportunistic networks