On the Experimental Evaluation of Vehicular Networks: Issues, Requirements and Methodology Applied to a Real Use Case

One of the most challenging fields in vehicular communications has been the experimental assessment of protocols and novel technologies. Researchers usually tend to simulate vehicular scenarios and/or partially validate new contributions in the area by using constrained testbeds and carrying out minor tests. In this line, the present work reviews the issues that pioneers in the area of vehicular communications and, in general, in telematics, have to deal with if they want to perform a good evaluation campaign by real testing. The key needs for a good experimental evaluation is the use of proper software tools for gathering testing data, post-processing and generating relevant figures of merit and, finally, properly showing the most important results. For this reason, a key contribution of this paper is the presentation of an evaluation environment called AnaVANET, which covers the previous needs. By using this tool and presenting a reference case of study, a generic testing methodology is described and applied. This way, the usage of the IPv6 protocol over a vehicle-to-vehicle routing protocol, and supporting IETF-based network mobility, is tested at the same time the main features of the AnaVANET system are presented. This work contributes in laying the foundations for a proper experimental evaluation of vehicular networks and will be useful for many researchers in the area.Comment: in EAI Endorsed Transactions on Industrial Networks and Intelligent Systems, 201

A framework for supporting network continuity in vehicular IPv6 communications

The appearance of recent standards about cooperative ITS architectures towards a reference communication stack has been an inflection point in the research about vehicular networks. The ISO Communication Access for Land Mobiles (CALM) and the ETSI European ITS communication architecture have paved the way towards real and interoperable vehicular cooperative systems. Within these convergent proposals, IPv6 communications are recognized as a key component to enable traffic efficiency and infotainment applications. The proper operation of these applications and the achievement of value-added ITS services require an uninterrupted network connectivity. This paper addresses this problem by proposing a novel communication stack to support the provision of continuous and secure IPv6 vehicular communications. The solution follows the ISO/ETSI guidelines for the development of cooperative ITS systems and is based on standardized technologies such as Network Mobility (NEMO) protocol to provide an integral management of IPv6mobility. The solution integrates IEEE 802.21 media independent handover services for optimizing the handover process. While the support to the handover optimization offered by the proposed ITS communication stack is demonstrated through a mobility use case, a real testbed supporting most of the communications features is developed to validate and assess the real performance of the stack design.This work has been sponsored by the European Seventh Framework Program, through the ITSSv6 (contract 270519) and FOTsis (contract 270447) projects; the Ministry of Science and Innovation, through the Walkie-Talkie project (TIN2011-27543-C03); and the Seneca Foundation, by means of the GERM program (04552/GERM/06)

Security in hybrid ITS networks

Dissertação para obtenção do Grau de Mestre em Engenharia Informática e de ComputadoresSistemas de Transportes Inteligentes e Cooperativos (C-ITS) visam melhorar a segurança e a sustentabilidade dos transportes. No entanto, a comunicação dos sistemas Vehicleto-Everything é inerentemente aberta, levando a vulnerabilidades que atacantes podem explorar. Isto é uma ameaça a todos os utilizadores rodoviários, pois falhas de segurança podem levar a violações de privacidade ou a fatalidades. Além disso, elevadas taxas de mortalidade estão correlacionadas com utilizadores de mobilidade suave. Logo, no desenvolvimento de sistemas C-ITS, é crucial considerar, além dos veículos conectados, os utilizadores de mobilidade suave e os veículos sem a devida tecnologia. Este estudo apresenta uma nova abordagem desenvolvida no contexto emergente das redes híbridas, combinando tecnologias ITS-G5 e celulares. Dois protocolos, MFSPV e DLAPP, foram implementados e avaliados para introduzir garantias de segurança (como privacidade e integridade) nas comunicações dentro do ambiente híbrido C-ITS desenvolvido. Assim, este trabalho integra, com segurança, estações ITS conectadas por G5 e utilizadores de mobilidade suave, através de uma aplicação móvel via redes celulares. Para tal, utilizou-se equipamentos reais, incluindo on-board e roadside units. Tempos computacionais, de latência e de ponta-a-ponta (E2E) foram usados para avaliar o desempenho do sistema. O protocolo MFSPV supera o DLAPP em eficiência computacional, mas o DLAPP atinge uma latência de rede ligeiramente menor. No entanto, ambos introduzem apenas um atraso adicional de 11% nas comunicações híbridas E2E. A comunicação híbrida impõe, em média, 28.29ms extra de tempo E2E. A proposta mostra-se promissora, visto que atinge tempos de E2E abaixo dos requisitos de latência impostos na maioria dos casos de utilização do C-ITS.Cooperative Intelligent Transport Systems (C-ITS) continue to be developed to enhance transportation safety and sustainability. However, the communication of Vehicle-to-Everything systems is inherently open, leading to vulnerabilities that attackers can exploit.This represents a threat to all road users, as security failures can lead to privacy violations or even fatalities. Moreover, a high fatality rate is correlated with softmobility road users. So, in the development of C-ITS systems, it is crucial to broaden the perspective beyond connected vehicles to soft-mobility users and legacy vehicles. This study presents a novel approach developed in the context of emerging hybrid networks, combining ITS-G5 and cellular technologies. Two protocols, MFSPV and DLAPP, were implemented and evaluated to introduce security guarantees (such as privacy and integrity) in communications within the developed C-ITS hybrid environment. As a result, this work securely integrates G5-connected ITS stations and softmobility users through a smartphone application via cellular networks. Real equipment was utilised for this goal, including on-board and roadside units. Computational, latency and end-to-end times were used to assess the system performance.MFSPV outperforms DLAPP in computational efficiency, but DLAPP achieves a slightly lower network latency. Nevertheless, both only introduce an additional 11% delay in hybrid end-to-end communications. Hybrid communication imposes, on average, an extra 28.29ms of end-to-end time. The proposal shows promise as it reaches end-to-end times below the latency requirements imposed in most C-ITS use cases.N/

Securing vehicular IPv6 communications

A common practice is applying security after a network has been designed or developed. We have the opportunity of not committing this error in vehicular networks. Apart from particular works in the literature, ETSI TC ITS has defined general security services for (vehicular) cooperative systems. However, existent efforts do not pay the needed attention to the integration of IPv6 yet. The potential of IPv6 in the field is being described within ISO TC 204, above all, but further work is needed for a proper integration of security. This work follows this direction, and a reference vehicular communication architecture considering ETSI/ISO regulations, uses Internet Protocol security (IPsec) and Internet Key Exchange version 2 (IKEv2) to secure IPv6 Network Mobility (NEMO). A key advance is also the implementation and experimental evaluation of the proposal in a challenging vertical handover scenario between 3G and 802.11p. The performance of the secured NEMO channel is widely analyzed in terms of the movement speed, bandwidth, traffic type or signal quality, and it is concluded that the addition of IPv6 security only implies a slight reduction in the overall performance, with the great advantage of providing confidentiality, integrity and authenticity to the communication path.This work has been sponsored by the EU 7th Framework Program through the ITSSv6, FOTsis, GEN6 and Inter-Trust projects (contracts 270519, 270447, 297239 and 317731), and the Ministry of Science and Innovation through the Walkie-Talkie project (TIN2011-27543-C03)

Enhancement AODV Routing Protocol at the VANET within an Urban Scenario

a vehicular ad hoc network (VANET) is a potential technology for supporting communication in vehicle-to-vehicle as well as vehicle-to-roadside units. Because of high mobility and periodic variations in the design of networks, creating a reliable routing strategy for these networks is one of the key challenges in VANETs. The Ad Hoc On-Demand Distance Vector (AODV) routing protocol's scalability and on-demand route discovery technique make it a popular choice in VANETs. However, AODV has limitations that might impair the performance of VANETs, including major control overhead and higher delays throughout the network. This work introduces an improved AODV routing protocol created especially for the VANETs. This paper analyzes the impacts of modifying the Contention Window (CW) settings for the density to discover ways to enhance the performance of the 802.11p transmission about receiving probabilities and latency. We show that the proposed CW specified in the IEEE 802.11p standard works well in almost all evaluated situations. The proposed protocol (P-AODV) also demonstrates robustness in extremely dynamic settings involving a range of traffic densities and patterns of movement

Towards seamless inter-technology handovers in vehicular IPv6 communications

Network mobility plays an important role in communications when using different access networks while maintaining application sessions. This is the case of vehicular networks used by the emerging Cooperative Intelligent Transport System (C-ITS), where vehicles are constantly moving, changing their access network. Standardization bodies like IETF, and particular proposals in the literature, have already defined mobility mechanisms by using widely used Internet technologies. The usefulness of these mechanisms in vehicular networks is clear when using IPv6, however, its performance suffer from the high mobility of nodes, the fluctuating performance of communication technologies, and the need for a decision mechanism to choose a proper attachment point among the available access networks on roads. For this reason, here we propose an instantiation of the ISO/ETSI reference architecture for vehicular cooperative systems, by deploying a real vehicular network based on IPv6, as well as a mobility service provided by Network Mobility Basic Support (NEMO) and the Multiple Care of Addresses Registration (MCoA) extension. This mobility solution is embedded into a framework that integrates the IEEE 802.21 technology, which provides a greater control over the handover process. The resulting architecture not only provides a seamless handover but also supports the decision making when searching for the most suitable target network. Our experiments reveal that our combined NEMO/MCoA/802.21 system within a vehicular communication stack is able to provide uninterrupted communications during handovers with a dramatic reduction in the time needed by this process.This work has been sponsored by the Spanish Ministry of Economy and Competitiveness through the EDISON project (contract TIN2014-52099-R) and the Spanish Department of Transport (DGT) through the S-CICLO project (contract SPIP2015-01757)

A network mobility management architecture for a heteregeneous network environment

Network mobility management enables mobility of personal area networks and vehicular networks across heterogeneous access networks using a Mobile Router. This dissertation presents a network mobility management architecture for minimizing the impact of handoffs on the communications of nodes in the mobile network. The architecture addresses mobility in legacy networks without infrastructure support, but can also exploit infrastructure support for improved handoff performance. Further, the proposed architecture increases the efficiency of communications of nodes in the mobile network with counter parts in the fixed network through the use of caching and route optimization. The performance and costs of the proposed architecture are evaluated through empirical and numerical analysis. The analysis shows the feasibility of the architecture in the networks of today and in those of the near future.Verkkojen liikkuuvudenhallinta mahdollistaa henkilökohtaisten ja ajoneuvoihin asennettujen verkkojen liikkuvuuden heterogeenisessä verkkoympäristössä käyttäen liikkuvaa reititintä. Tämä väitöskirja esittää uuden arkkitehtuurin verkkojen liikkuvuudenhallintaan, joka minimoi verkonvaihdon vaikutuksen päätelaitteiden yhteyksiin. Vanhoissa verkoissa, joiden infrastruktuuri ei tue verkkojen liikkuvuutta, verkonvaihdos täytyy hallita liikkuvassa reitittimessa. Standardoitu verkkojen liikkuvuudenhallintaprotokolla NEMO mahdollistaa tämän käyttäen ankkurisolmua kiinteässä verkossa pakettien toimittamiseen päätelaitteiden kommunikaatiokumppaneilta liikkuvalle reitittimelle. NEMO:ssa verkonvaihdos aiheuttaa käynnissä olevien yhteyksien keskeytymisen yli sekunnin mittaiseksi ajaksi, aiheuttaen merkittävää häiriötä viestintäsovelluksille. Esitetyssä arkkitehtuurissa verkonvaihdon vaikutus minimoidaan varustamalla liikkuva reititin kahdella radiolla. Käyttäen kahta radiota liikkuva reititin pystyy suorittamaan verkonvaihdon keskeyttämättä päätelaitteiden yhteyksiä, mikäli verkonvaihtoon on riittävästi aikaa. Käytettävissa oleva aika riippuu liikkuvan reitittimen nopeudesta ja radioverkon rakenteesta. Arkkitehtuuri osaa myös hyödyntää infrastruktuurin tukea saumattomaan verkonvaihtoon. Verkkoinfrastruktuurin tuki nopeuttaa verkonvaihdosprosessia, kasvattaenmaksimaalista verkonvaihdos tahtia. Tällöin liikkuva reitin voi käyttää lyhyen kantaman radioverkkoja, joiden solun säde on yli 80m, ajonopeuksilla 90m/s asti ilman, että verkonvaihdos keskeyttää päätelaitteiden yhteyksiä. Lisäksi ehdotettu arkkitehtuuri tehostaa kommunikaatiota käyttäen cache-palvelimia liikkuvassa ja kiinteässä verkossa ja optimoitua reititystä liikkuvien päätelaitteiden ja kiinteässä verkossa olevien kommunikaatiosolmujen välillä. Cache-palvelinarkkitehtuuri hyödyntää vapaita radioresursseja liikkuvan verkon cache-palvelimen välimuistin päivittämiseen. Heterogeenisessä verkkoympäristossä cache-palvelimen päivitys suoritetaan lyhyen kantaman laajakaistaisia radioverkkoja käyttäen. Liikkuvan reitittimen siirtyessä laajakaistaisen radioverkon peitealueen ulkopuolelle päätelaitteille palvellaan sisältöä, kuten www sivuja tai videota cache-palvelimelta, säästäen laajemman kantaman radioverkon rajoitetumpia resursseja. Arkkitehtuurissa käytetään optimoitua reititystä päätelaitteiden ja niiden kommunikaatiokumppaneiden välillä. Optimoitu reititysmekanismi vähentää liikkuvuudenhallintaan käytettyjen protokollien langattoman verkon resurssien kulutusta. Lisäksi optimoitu reititysmekanismi tehostaa pakettien reititystä käyttäen suorinta reittiä kommunikaatiosolmujen välillä. Esitetyn arkkitehtuurin suorituskyky arvioidaan empiirisen ja numeerisen analyysin avulla. Analyysi arvioi arkkitehtuurin suorituskykyä ja vertaa sitä aikaisemmin ehdotettuihin ratkaisuihin ja osoittaa arkkitehtuurin soveltuvan nykyisiin ja lähitulevaisuuden langattomiin verkkoihin.reviewe