Carlos Borrego

A store-carry-process-and-forward paradigm for intelligent sensor grids

Store-carry-and-forward DTN (Delay/Disruption Tolerant Networking) protocols offer new possibilities in scenarios where there is intermittent connectivity, asymmetric bandwidths, long and variable latency and ambiguous mobility patterns. In this article we propose a new paradigm -store-carry-process-and-forward - based on mobile code to improve the integration of wireless sensor networks and grid computing infrastructures. We describe the implementation of a delay tolerant grid service, the computer element, to give computing access to an intermittently connected wireless sensor network. The result is an intelligent system which adapts dynamically to intermittent disconnections and improves multi-application coexistence. Finally, we present as an example a real case application which provides general purpose grid access to a multi-application mobile robot node sensor network.

Striving for sensing: Taming your mobile code to share a robot sensor network

Abstract This article presents a general purpose, multi-application mobile node sensor network based on mobile code. This intelligent system can work in delay and disruption tolerant (DTN) scenarios. Mobile nodes host software mobile code with task missions and act as DTN routers following the store-carry-and-forward paradigm. Most similar proposals are unable to simultaneously run different applications, with different routing algorithms, movement models, and information retrieval strategies. The keystone of the approach in this paper is using mobile code at two levels: for the application, and for the definition of the behavior in terms of routing algorithms, movement policies and sensor retrieval preferences. The intelligence of the system lies in its ability to adapt to the environment, dynamically optimizing routing algorithms using local and global information and influencing node movement. Simulations and an implementation of a real scenario have been undertaken to prove the feasibility and usability of the system, and to study its performance. A proposal for a real-world application in the context of refugee camp management is presented.

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.

Softwarecast: A code-based delivery Manycast scheme in heterogeneous and Opportunistic Ad Hoc Networks

Abstract In the context of Opportunistic Ad Hoc Networking paradigms, group communication schemes (Manycast) are difficult to conduct. In this article, we propose a general delivery scheme for Manycast group communications based on mobile code. Our proposal extends network addressing by moving from the static header field paradigm to a software code-based addressing scheme. We allow messages to be delivered using built-in software codes that consider application-defined, context-aware or history-based information. Additionally, we allow messages to carry a delivery state that permits them to perform refined delivery-decision-making methods. As a consequence of this scheme, we have found that new group communication schemes, besides the traditional ones, may be beneficial to improve the network performance and to provide new functionalities to emerging scenarios like intermittently connected networks of heterogeneous physical objects. We present an application of this scheme to solve, following an analytical delivery method, the problem of sending a message to k and only k nodes of a heterogeneous and opportunistic network scenario that fit best a given criterion. We show, using simulations, that our proposal performs better than traditional approaches. Finally, to show that our proposal is feasible, we present an implementation of our proposal in a real Opportunistic Ad Hoc network, a DTN network, compatible with the de facto standard Bundle Protocol.

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.

Relative Information in Grid Information Service and Grid Monitoring Using Mobile Agents

Grid computing is consolidated as a technology capable of solving scientific projects of our century. These projects’ needs include complex computational and large data storage resources. The goal of grid Computing is to share these resources among different institutes and virtual organizations across high-speed networks. The more resources there are the more difficult it gets to monitor them and to assure users find the best resources they are looking for. We introduce the concept of relative information to enhance grid information and grid monitoring services. Resource relative information is information that is not only gathered from the resource itself but also that takes into account other resources of the same type. The resource is not described in terms of the resource local information but also relative to other resources. We present a framework based on mobile agents that enables to publish relative information in the grid information service and another framework to monitor grid resources using relative criteria.

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.