Adrián Sánchez-Carmona

Mobile-Agent Based Delay-Tolerant Network Architecture for Non-critical Aeronautical Data Communications

The future air transportation systems being developed under the NextGen (USA) and SESAR (European Commission) research initiatives will imply new levels of connectivity requirements between the concerned parties. Within this new aeronautical connectivity scenario, this paper proposes a new communication architecture for non-critical delay-tolerant communication (e.g. passenger data communications such as email and news services and non-critical telemetry data) based on mobile agents.Mobile agents carry both the user data and the routing algorithm used to decide the next hop in the path to the final destination. Therefore, mobile agents allow to increase the dynamism of the routing process. The proposed architecture constitutes an evolution of DTN (Delay Tolerant Networks), more flexible than the traditional layer-based approaches such as the Bundle Protocol and Licklider Transmission Protocol (LTP). This paper also presents the results obtained after network emulation and field experimentation of our proposed architecture.

PrivHab+: A secure geographic routing protocol for DTN

Abstract We present PrivHab+, a secure geographic routing protocol that learns about the mobility habits of the nodes of the network and uses this information in a secure manner. PrivHab+ is designed to operate in areas that lack of network, using the store-carry-and-forward approach. PrivHab+ compares nodes and chooses the best choice to carry messages towards a known geographical location. To achieve a high performance and low overhead, PrivHab+ uses information about the usual whereabouts of the nodes to make optimal routing decisions. PrivHab+ makes use of cryptographic techniques from secure multi-party computation to preserve nodes’ privacy while taking routing decisions. The overhead introduced by PrivHab+ is evaluated using a proof-of-concept implementation, and its performance is studied under the scope of a realistic application of podcast distribution. PrivHab+ is compared, through simulation, with a set of well-known delay-tolerant routing algorithms in two different scenarios of remote rural areas.

A mobile code bundle extension for application-defined routing in delay and disruption tolerant networking

In this paper, we introduce software code to improve Delay and Disruption Tolerant Networking (DTN) performance. DTN is extremely useful when source and destination nodes are intermittently connected. DTN implementations use application-specific routing algorithms to overcome those limitations. However, current implementations do not support the concurrent execution of several routing algorithms. In this paper, we contribute to this issue providing a solution that consists on extending the messages being communicated by incorporating software code for forwarding, lifetime control and prioritisation purposes. Our proposal stems from the idea of moving the routing algorithms from the host to the message. This solution is compatible with Bundle Protocol (BP) and facilitates the deployment of applications with new routing needs. A real case study based on an emergency scenario is presented to provide details of a real implementation. Several simulations are presented to prove the feasibility and usability of the system and to analyse its performance in comparison to state-of-the-art approaches.

Explore and wait: A composite routing-delivery scheme for relative profile-casting in opportunistic networks

Abstract In the context of Opportunistic Networking (OppNet), designing routing and delivery protocols is currently an open and active line of research. In some OppNet scenarios, destination addresses are not always known by sending applications. Profile-cast models solve this problem by allowing message destinations to be users or groups of users defined by their profiles. These profiles provide very effective ways of characterizing nodes in terms of node’s attributes such as their profession, interests or typical whereabouts, for example. However, there are strong limitations in OppNet Profile-casting. There is no current way of representing special profiles defined by relative delivery functions such as best, maximum or over-the-average : nodes belong to these relative profiles taking into account not only attributes from the very same node but also relative to others from the same profile. In this article, we introduce Relcast, a Profile-cast model that allows messages to be sent to profiles defined in terms of relative delivery functions. Additionally, we present Explore and Wait, a composite routing-delivery scheme that uses optimal stopping theory-based delivery strategies to route Relcast messages. We show, using simulations, that this routing-delivery scheme performs better than traditional approaches that use state-of-the-art routing-delivery primitives.

PrivHab: A privacy preserving georouting protocol based on a multiagent system for podcast distribution on disconnected areas

Abstract We present PrivHab, a privacy preserving georouting protocol that improves multiagent decision-making. PrivHab learns the mobility habits of the nodes of the network. Then, it uses this information to dynamically select to route an agent carrying a piece of data to reach its destination. PrivHab makes use of cryptographic techniques from secure multi-party computation to make the decisions while preserving nodes’ privacy. PrivHab uses a waypoint-based routing that achieves a high performance and low overhead in rugged terrain areas that are plenty of physical obstacles. The store-carry-and-forward approach used is combined with mobile agents that provide intelligence, and it is designed to operate in areas that lack network infrastructure. We have evaluated PrivHab under the scope of a realistic podcast distribution application in remote rural areas, where these programs have to be recorded into a physical format and distributed to the local radio stations. The usage of PrivHab aims to reduce this spending of resources. The PrivHab protocol is compared with a set of well-known delay-tolerant routing algorithms and shown to outperform them.

Podcast Distribution on Gwanda Using PrivHab: A Multiagent Secure Georouting Protocol

We present PrivHab, a georouting protocol that improves multiagent systems itinerary decision-making. PrivHab uses the mobility habits of the nodes of the network to select an itinerary for each agent carrying a piece of data. PrivHab makes use of cryptographic techniques to make the decisions while preserving nodes’ privacy. PrivHab uses a waypoint-based georouting that achieves a high performance and low overhead in rugged terrain areas that are plenty of physical obstacles. The store-carry-and-forward approach used is based on mobile agents and is designed to operate in areas that lack network infrastructure. We have evaluated PrivHab under the scope of a realistic podcast distribution application in remote rural areas. The PrivHab protocol is compared with a set of well-known delay-tolerant routing algorithms and shown to outperform them.

Two birds, one stone: Using mobility behavioral profiles both as destinations and as a routing tool

Abstract We present HabCast, a profile-cast communication paradigm that learns about the mobility habits of the location-aware nodes of the network and uses this information both to route the messages, and to deliver them only to the nodes that match the target behavioral profile. HabCast substitutes destinations identifier by a mobility profile model called habitat, meaning that allows users to send messages “to any nodes who usually roams around this area” instead of sending messages intended to a node. HabCast is designed to operate without network infrastructure, using Opportunistic Networking strategies and operates in three phases: approximation, floating and delivery phase. HabCast enables new services and applications on Opportunistic Networking by automatically inferring the nodes’ behavioral profiles and using them to define the messages’ destinations. The overhead introduced by HabCast is evaluated using a proof-of-concept implementation, and its performance and feasibility is studied, through simulation, under the scope of a real carsharing application.

Endeavouring to be in the good books. Awarding DTN network use for acknowledging the reception of bundles

This paper describes an incentive scheme for promoting the cooperation, and, therefore, avoiding selfish behaviours, in Delay Tolerant Networks (DTN) by rewarding participant nodes with cryptographic keys that will be required for sending bundles. DTN are normally sparse, and there are few opportunistic contacts, so forwarding of others bundles can be left out. Moreover, it is difficult to determine the responsible nodes in case of bundle loss. The mechanism proposed in this paper contributes to both problems at the same time. On one hand, cryptographic receipts are generated using time-limited Identity Based Cryptography (IBC) keys to keep track of bundle transmissions. On the other hand, these receipts are used to reward altruistic behaviour by providing newer IBC keys. Finally, these nodes need these IBC keys to send their own bundles. When all nodes behave in a cooperative way, this incentive scheme works as a virtuous circle and achieves a Nash equilibrium, improving very much the network performance in terms of latency. The scheme is not difficult to implement, and it can use an already existing IBC infrastructure used for other purposes in a DTN.

Filling in the missing link between simulation and application in opportunistic networking

In the domain of opportunistic networking, just like in any other domain of computer science, the engineering process should span all stages between an original idea and the validation of its implementation in real conditions. Yet most researchers often stop halfway along this process: they rely on simulation to validate the protocols and distributed applications they design, and neglect to go further. Their algorithms are thus only rarely implemented for real, and when they are, the validation of the resulting code is usually performed at a very small scale. Therefore, the results obtained are hardly repeatable or comparable to others. LEPTON is an emulation platform that can help bridge the gap between pure simulation and fully operational implementation, thus allowing developers to observe how the software they develop (instead of pseudo-code that simulates its behavior) performs in controlled, repeatable conditions. In this paper we present LEPTON, an emulation platform we developed, and we show how existing opportunistic networking systems can be adapted to run with this platform. Taking two existing middle-ware systems as use cases, we also demonstrate that running demanding scenarios with LEPTON constitute an excellent stress test and a powerful tool to improve the opportunistic systems under test.