Middleware for the Internet of Things, Design Goals and Challenges

As the number of wireless devices increases and their size becomes smaller, there can be more interaction between everyday objects of our life. With advances in RFID chips and the introduction of new generations of these devices that are smaller and cheaper, it is possible to put a wireless interface on almost all everyday objects: vehicles, clothes, foodstuffs, etc. This concept is called the \textit{Internet of Things}. Interaction with thousands of wireless devices leads to a continuous and massive flow of events which are generated spontaneously. The question of how to deal with this enormous number of events is challenging and introduces new design goals for a communication mechanism. In this paper we argue that a middleware together with suitable linguistic abstractions is a proper solution. We also point out the challenges in developing this middleware. Moreover, we give an overview of recent related work and describe why they fail to address these challenges

Evaluation of Caching Strategies in Content-Centric Networking (CCN) for Mobile and Social Networking Environment

Users of the Internet are still using the basic network communication model that was created way back 1960s. The grand idea of migration from host-centric to information-centric has made Content-Centric Networking (CCN) one of the eminent candidates for the future internet. The extension of caching technology as one of the components in the networking itself require deeper thought than just plug and play of current web or server caching techniques. While most studies are focusing on new caching strategies, this study will highlight the gaps by comparing common caching strategies in different predicted scenario of the future. The evaluation was done using simulation tools known as SocialCCNSim focusing on six relevant caching strategies: Leave Copy Everywhere (LCE), Leave Copy Down (LCD), ProbCache, Cache “Less for More”, MAGIC and Randomly Copy One (RCOne) in different network topologies: Tree and Diamond. Rank is given based on metrics such as Cache Hit, Stretch, Diversity and Eviction operations that represented the most commonly used metrics in networking. Results show that all caching strategies have their own behavior toward different network topology. However, Cache “Less for More” considered the best with balanced result for both performance and resource utilization metrics

Cooperation as a Service in VANET: Implementation and Simulation Results

The past decade has witnessed the emergence of Vehicular Ad-hoc Networks (VANET), specializing from the well-known Mobile Ad Hoc Networks (MANET) to Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) wireless communications. While the original motivation for Vehicular Networks was to promote traffic safety, recently it has become increasingly obvious that Vehicular Networks open new vistas for Internet access, providing weather or road condition, parking availability, distributed gaming, and advertisement. In previous papers [27,28], we introduced Cooperation as a Service (CaaS); a new service-oriented solution which enables improved and new services for the road users and an optimized use of the road network through vehicle\u27s cooperation and vehicle-to-vehicle communications. The current paper is an extension of the first ones; it describes an improved version of CaaS and provides its full implementation details and simulation results. CaaS structures the network into clusters, and uses Content Based Routing (CBR) for intra-cluster communications and DTN (Delay and disruption-Tolerant Network) routing for inter-cluster communications. To show the feasibility of our approach, we implemented and tested CaaS using Opnet modeler software package. Simulation results prove the correctness of our protocol and indicate that CaaS achieves higher performance as compared to an Epidemic approach

Cooperation as a Service in VANET: Implementation and Simulation Results

The past decade has witnessed the emergence of Vehicular Ad-hoc Networks (VANET), specializing from the well-known Mobile Ad Hoc Networks (MANET) to Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) wireless communications. While the original motivation for Vehicular Networks was to promote traffic safety, recently it has become increasingly obvious that Vehicular Networks open new vistas for Internet access, providing weather or road condition, parking availability, distributed gaming, and advertisement. In previous papers [27,28], we introduced Cooperation as a Service (CaaS); a new service-oriented solution which enables improved and new services for the road users and an optimized use of the road network through vehicle's cooperation and vehicle-to-vehicle communications. The current paper is an extension of the first ones; it describes an improved version of CaaS and provides its full implementation details and simulation results. CaaS structures the network into clusters, and uses Content Based Routing (CBR) for intra-cluster communications and DTN (Delay–and disruption-Tolerant Network) routing for inter-cluster communications. To show the feasibility of our approach, we implemented and tested CaaS using Opnet modeler software package. Simulation results prove the correctness of our protocol and indicate that CaaS achieves higher performance as compared to an Epidemic approach

A self repairing tree topology enabling content-based routing in mobile ad hoc networks

Abstract — Content-based routing (CBR) provides a powerful and flexible foundation for distributed applications. Its communication model, based on implicit addressing, fosters decoupling among the communicating components, therefore meeting the needs of many dynamic scenarios, including mobile ad hoc networks (MANETs). Unfortunately, the characteristics of the CBR model are only rarely met by available systems, which typically assume that application-level routers are organized in a tree-shaped network with a fixed topology. In this paper we present COMAN, a protocol to organize the nodes of a MANET in a tree-shaped network able to i) selfrepair to tolerate the frequent topological reconfigurations typical of MANETs; ii) achieve this goal through repair strategies that minimize the changes that may impact the CBR layer exploiting the tree. COMAN is implemented and publicly available. Here we report about its performance in simulated scenarios as well as in real-world experiments. The results confirm that its characteristics enable reliable and efficient CBR on MANETs. Index Terms — Content-based routing, publish-subscribe, query-advertise, mobile ad hoc network

Luotettavuus ad hoc -verkoissa

Ad hoc -verkko on verkko, joka rakennetaan ja muodostetaan kahden tai useamman tietoteknisen laitteen välille ilman tukiasemaa. Ad hoc -verkon laitteet kommunikoivat keskenään ilman erillistä tukiasemaa ja jos verkossa useampia laitteita ja kaikki laitteet eivät ole toistensa kuuluvuusalueella silloin laitteet toimivat myös reitittiminä toimitta-maan viestit oikeille vastaanottajille. Ad hoc -verkko voi olla langallinen tai langaton verkko tai niiden yhdistelmä. Jos ad hoc -verkko on langaton, niin se tosi edullinen ra-kentaa, kun ei tarvita erillisiä laitteita reitittämiseen. Luotettavuus on tärkeä asia elämässä, niin se on myös viestinnässäkin erityisesti verkko-viestinnässä. Työn tavoitteena on selvittää, miten luotettavuus toteutetaan ad hoc -verkoissa. Tutustutaan, mitä luotettavuus tarkoittaa ja miten luotettavuuden eri osa-alueet toteutetaan. Käydään läpi joitain ad hoc -verkkoratkaisuja. Mobiili ad hoc -verkko luo reitittämiseen haastetta liikkuvuuden takia. Mobiililaitteissa on usein vähän muisti-kapasiteettia ja laitteiden virrankulutus voi olla korkea. Työssä käsitellään reititysproto-kollia varsinkin langattomaan tekniikkaan liittyen. Työ esittelee erilaisia reititysprotokol-lia ja miten reititysprotokollat voidaan luokitella ominaisuuksiensa tai toimintatapansa perusteella. Esimerkkeinä esitellään useita protokollia pääpiirteittäin ja lähemmin pereh-dytään reititysprotokollien kahteen laatupalveluun, joilla parannetaan reitityksen laatua ja sitä kautta reitityksen luotettavuutta. Reititysprotokollien tarkoituksena on toimia niin, että paketit toimitettaisiin perille vastaanottajalle lyhyintä, nopeinta ja luotettavinta reit-tiä pitkin. Työssä esitetään, miten reititysprotokollat hoitavat reitityksen ja siihen liitty-vät asiat kuten esimerkiksi ruuhkanhallinnan, verkon kuormituksen, pakettien ja reititys-tietojen päivitykset. Toiset reititysprotokollat soveltuvat paremmin pieniin verkkoihin ja toiset taas vähän paremmin laajempiin verkkoihin. Ja siinäkin on isoja eroja, miten reititysprotokollat selviävät verkon topologiamuutoksista

Disseminação de dados em redes de sensores

Tese de mestrado, Engenharia Informática (Arquitectura, Sistemas e Redes de Computadores), Universidade de Lisboa, Faculdade de Ciências, 2010As redes de sensores sem fios (RSSF) são compostas por um grande número de pequenos dispositivos que monitorizam o ambiente em que estão inseridas. Estes dispositivos são caracterizados pelas restrições a nível energético, poder de processamento e de memória. As fortes restrições a que os dispositivos estão sujeitos obrigam à utilização de paradigmas de comunicação específicos, que tenham em consideração uma utilização racional dos recursos. Com a especialização dos nós receptores surge a necessidade destes conseguirem expressar o interesse em informação que considerem relevante, independentemente dos restantes participantes. O paradigma de comunicação usado tipicamente nas RSSF não considera os interesses que os nós receptores têm na informação que está a ser transmitida, pelo que pode ser enviado um grande número de mensagens nas quais nenhum nó receptor está interessado. O envio de mensagens desnecessárias é particularmente penalizador nas RSSF, uma vez que a actividade do rádio é responsável pelo consumo de grande parte da energia que os dispositivos dispõem. Sendo a memória um recurso escasso, importa também que o paradigma de comunicação seja igualmente eficiente em termos da quantidade de memória utilizada. Este trabalho apresenta e avalia experimentalmente um sistema Publicador/Subscritor que tem em conta o interesse dos nós em determinados tipos de informação e suprime o envio de informação sem relevância. Para além disso, o sistema adapta-se às restrições de energia e de memória dos dispositivos. Adicionalmente é apresentada uma concretização dum algoritmo de disseminação para o sistema operativo TinyOS que sugere que o sistema apresentado é exequível em sensores reais.Wireless sensor networks (WSN) are composed of a large number of small devices which monitor the environment in which they operate. These devices are characterized by restrictions like energy, processing and memory. The strong restrictions on the devices enforce the use of paradigms of communication which take into account a rational use of resources. With the specialization of the receptor nodes arises the need for them to be able express interest in information they deem relevant, regardless the interests of other participants. The paradigm of communication typically used in WSNs does not consider the receivers’ interests in information being transmitted, so it is possible to send a large number of messages in which no receiver node is interested. Sending unnecessary messages is particularly expensive in WSNs, since the activity of the radio is responsible for consuming much of the power the devices have. Since memory is a scarce resource, the paradigm of communication must also be efficient in the amount of memory used. This work presents and experimentally evaluates a Publisher/Subscriber system which takes into account the interest of the nodes in certain types of information and suppresses the sending of information without relevance. In addition, the system adapts to the resource constraints of devices such as reduced energy capacity and scarce memory space. Additionally, an implementation of an dissemination algorithm to the TinyOS operating system is presented. This implementation suggests that the presented system is feasible in real sensors