In this article, we address the problem of optimal flow allocation in the context of industrial networks. The problem is known to be computationally hard, which makes it difficult to solve for large networks. Moreover, industrial networks, such as power grids, often have unique characteristics, for example, integral flows and delay-symmetric path requirements, which further constrain the problem. To address these challenges, we propose the Simulated Annealing-based Flow Allocation Rules (SAFAR) scheme. At a high level, SAFAR identifies the near-optimal paths satisfying the bandwidth demands of a subset of flows by iteratively considering several configurations. The optimality criteria herein corresponds to maximizing the number of flows for which bandwidth paths are obtained, as well as improving the relative fairness in link utilization arising out of the process. Subsequently, SAFAR assigns a fraction of bandwidth (slice) to the remaining flows. Finally, SAFAR generates appropriate forwarding rules for the switches. Results of performance evaluation using real-life and synthetically-generated networks reveal that SAFAR can allocate up to 99% flows, which is an improvement of up to 9.6% over a contemporary greedy scheme. Moreover, SAFAR can improve the flow allocation fairness relatively by up to 37%. Finally, we also use a network of Open vSwitch switches to verify the end-to-end functionality of SAFAR.

Opportunistic Mobile Networks (OMNs) enable communication among the otherwise disconnected devices via intermittent contacts. Based on this premise, the paradigms of Opportunistic Computing (OC) and Opportunistic Service Provisioning (OSP) were proposed, where a user can request remotely available hardware and software services from the relevant nodes that are not in direct contact with the user's device. In this work, we consider the problem of OSP together with ordered chaining. Chaining (or composition) refers to the scenario where two or more services must be availed by a given data object one after the another, for example, translating a text file and converting it to another format. Such a chaining is termed as ordered when the required services must be availed in a specific sequence. We discuss four schemes for achieving OSP with ordered chaining. One of the proposed schemes unicasts the OSP request messages, while another one adapts a popular unicasting algorithm for OMNs. The third scheme is based on flooding, whereas in the final one, nodes replicate requests only to those who provide the concerned services. The results of performance evaluation using real-life traces and synthetic mobility models show that up to about 99 percent of the service requests can be satisfied. The results also indicate that unicasting is rather unsuitable to achieve OSP.

In this work, we address the problem of Named Data Networking (NDN)-based fake content dissemination in Opportunistic Mobile Networks (OMNs), where nodes have intermittent connectivity and typically lack in end-to-end communication paths. It is important to mitigate the dissemination of such fake contents not only because they waste bandwidth for legitimate communication, but also because such files can be harmful for devices. However, the inherent characteristics of OMNs make such mitigation a challenging task. In this context, we consider a group of nodes, Fake Content Providers (FCPs), who, on receiving content requests, respond with fake contents, rather than the real version. In particular, we consider four different behaviors of the FCPs-referred to as threat scenarios-depending on whether or not they always respond to all requests with fake contents. We analyze these distinct threat scenarios, and characterize the relative performance degradation arising because of them. To mitigate the adverse effects of FCPs, we propose two schemes, wherein the identified FCPs are blacklisted permanently or temporarily, and communication with them is restricted. Results of simulation-based experiments using real-life connection traces show that, compared to the normal scenario with no FCP, the percentage of content requests satisfied decreases by 20-40 percent in the presence of 40 percent FCPs in the OMN. Moreover, in the same scenario, the average latency of content satisfaction relatively increases by up to 176 percent with respect to the normal scenario. However, on using the proposed mitigation schemes, the latency can be reduced by about 13-36 percent together with up to 9 percent improvement in the number of interests satisfied.

In cooperative communication, a set of players forming a coalition ensures communal behavior among themselves by helping one another in message forwarding. Opportunistic mobile networks (OMNs) require multihop communications for transferring messages from the source to the destination nodes. However, noncooperative nodes only forward their own messages to others, and drop others' messages upon receiving them. So, the message delivery overhead increases in OMN. For minimizing the overhead and maximizing the delivery rate, we propose two coalition-based cooperative schemes: 1) simple coalition formation (SCF) and 2) overlapping coalition formation (OCF) game. In SCF, we consider the presence of a central information center, whereas OCF is a fully distributed scheme. In SCF, coalitions are disjoint, whereas in OCF, a node may be the member of multiple coalitions at the same time. All nodes in a coalition help each other cooperatively by forwarding group messages to the intermediate or destination nodes. The goal of the nodes is to achieve high success rate in delivering messages. The proposed SCF scheme is cohesive, in which disjoint coalitions always combine to form grand coalition. In OCF, a node reaches a stable grand coalition when all the nodes of the OMN are members of overlapping coalition of the node. No node gains by deviating from the grand coalition in SCF and OCF. Simulation results based on synthetic mobility model and real-life traces show that the message delivery ratio of OMNs increase by up to 67%, as compared to the noncooperative scenario. Moreover, the message overhead ratio using the proposed coalition-based schemes reduces by up to about (1/3)rd of that of the noncooperative communication scheme.

Opportunistic Mobile Networks (OMNs) are characterized by intermittent connectivity among nodes. In many scenarios, the nodes attempt at local decision making based on greedy approaches, which can result in getting trapped at local optimum. Moreover, for efficient routing, the nodes often collect and exchange a lot of information about others. To alleviate such issues, we present SeeR, a simulated annealing-based routing protocol for OMNs. In SeeR, each message is associated with a cost function, which is evaluated by considering its current hop-count and the average aggregated inter-contact time of the node. A node replicates a message to another node, when the latter offers a lower cost. Otherwise, the message is replicated with decreasing probability. Moreover, SeeR works based solely upon local observations. In particular, a node does not track information about other nodes, and, therefore, reduces the risk of privacy leaks unlike many other protocols. We evaluated the performance of SeeR by considering several real-life traces under plausible conditions. Experimental results show that, in the best case, SeeR can reduce the average message delivery latency by about 58 percent, when compared to other popular routing protocols.

Opportunistic mobile networks (OMNs), which are formed by mobile devices carried by human users, present an interesting communication paradigm in the absence of access to global network connectivity or any form of network infrastructure. In this work, we combine thenaturalmobility of the human users—which has been shown to resemble Levy Walk—in OMNs, together with intentionalexplorations. We consider the case where the human users in an OMN undergo explorations, i.e., occasionally visit a set of fixed point of interests (PoI), for example, shopping malls. The objective of this work is two-fold-1) Establishing that limited explorations of the users can help in enhancing the performance of OMNs, and 2) Formulating a method to decide whether or not a user should undergo exploration. In this regard, we propose two schemes based on prospect theory (PT) and expected utility theory (EUT). The results of extensive simulation-based performance evaluation indicate that limited exploration can promote the delivery ratio of messages by large levels—about$7$-$33$percent depending on the number of randomly placed PoI, and about$36$percent depending upon the terrain size. Moreover, the time spent in exploration, on an average, is negligibly small—a typical value is about$0.55$percent of the simulation duration, which indicates its feasibility in real life.

Cooperation among nodes is a fundamental necessity in opportunistic mobile networks (OMNs), where the messages are transferred using the store-carry-and-forward mechanism, due to sporadic inter-node wireless connectivity. While multiple works have addressed this issue, they are often constrained in their assumptions on solutions (e.g., requirement of central authority, and tracing the recipient nodes for providing reward or punishment). In this work, we address this research lacuna by taking an evolutionary theory-based approach. In evolutionary theory, the players analyze alternative strategies and select the best one to survive in a population. Inspired by this, in this work, we propose a Distributed Information-Based Cooperation Ushering Scheme (DISCUSS) to promote cooperation in message forwarding between nodes. In this scheme, the nodes maintain and exchange information with one another during contacts about the messages created and delivered in the network. Based on this, the nodes evaluate their own performance and compare that with the approximated network performance to adapt the most successful forwarding strategy. Simulation results show that the message delivery ratio in the network improves upto 31 percent, when the nodes dynamically switch their strategies, as compared to the case when they do not. Furthermore, the DISCUSS scheme fared closely to its variant with the nodes having complete knowledge about the network-wide performance.