Towards a versatile transport protocol

n the context of a reconfigurable transport protocol, this paper introduces two protocol instances based on the com- position and specialisation of the TFRC congestion control and Selective Acknowledgment mechanisms. The two result- ing transport architectures lead respectively to the QTP_AF protocol, specifically designed to operate over QoS-enabled networks and the QTP_light protocol, specifically designed for resource-limited end systems connected to powerful servers. QTP_AF combines QoS-aware TFRC congestion control with full reliability to provide a transport service similar to TCP but additionally taking into account network-level band-width reservations. QTP_light proposes a modification of TFRC that shifts from the receiver to the sender the complexity of the loss rate estimation mechanism. This modification allows to alleviate the processing and communication load of "light" resource limited mobile receivers. We present the concept of these protocols and their adaptation in the EuQoS European project framework

Towards a sender-based TCP friendly rate control (TFRC) protocol

Pervasive communications are increasingly sent over mobile devices and personal digital assistants. This trend is currently observed by mobile phone service providers which have measured a significant increase in multimedia traffic. To better carry multimedia traffic, the IETF standardized a new TCP Friendly Rate Control (TFRC) protocol. However, the current receiver-based TFRC design is not well suited to resource limited end systems. In this paper, we propose a scheme to shift resource allocation and computation to the sender. This sender-based approach led us to develop a new algorithm for loss notification and loss-rate computation. We detail the complete implementation of a user-level prototype and demonstrate the gain obtained in terms of memory requirements and CPU processing compared to the current design. We also evaluate the performance obtained in terms of throughput smoothness and fairness with TCP and we note this shifting solves security issues raised by classical TFRC implementations

Towards sender-based TFRC

Pervasive communications are increasingly sent over mobile devices and personal digital assistants. This trend has been observed during the last football world cup where cellular phones service providers have measured a significant increase in multimedia traffic. To better carry multimedia traffic, the IETF standardized a new TCP Friendly Rate Control (TFRC) protocol. However, the current receiver-based TFRC design is not well suited to resource limited end systems. We propose a scheme to shift resource allocation and computation to the sender. This sender based approach led us to develop a new algorithm for loss notification and loss rate computation. We demonstrate the gain obtained in terms of memory requirements and CPU processing compared to the current design. Moreover this shifting solves security issues raised by classical TFRC implementations. We have implemented this new sender-based TFRC, named TFRC_light, and conducted measurements under real world conditions

Understanding and modeling the small-world phenomenon in dynamic networks

The small-world phenomenon first introduced in the context of static graphs consists of graphs with high clustering coefficient and low shortest path length. This is an intrinsic property of many real complex static networks. Recent research has shown that this structure is also observable in dynamic networks but how it emerges remains an open problem. In this paper, we propose a model capable of capturing the small-world behavior observed in various real traces. We then study information diffusion in such small-world networks. Analytical and simulation results with epidemic model show that the small-world structure increases dramatically the information spreading speed in dynamic networks

L’institutionnalisation d’une égalité dans la différence : parité, diversité, intersectionnalité

L’invention contemporaine de la parité et de la diversité en France interroge la compatibilité entre la notion républicaine d’égalité dans une tradition universaliste réputée en crise, la notion d’identité dans un contexte multiculturel et la notion d’utilité au nom d’un libéralisme vertueux. En écho aux recherches dénonçant l’institutionnalisation française de la promotion de la parité et de la diversité comme une dépolitisation refoulant le répertoire conflictuel de l’anti-discrimination et occultant les rapports de pouvoir, en particulier leur sexualisation et leur « racialisation », notre propos est d’explorer en quoi cette dépolitisation est politique. Pour cela, nous analyserons les liens entre la grammaire de l’injustice et les théories de la justice dans les débats internationaux sur l’intersectionnalité. Comment l’égalité, pensée comme valeur, objectif et droit, résiste-t-elle à l’émergence du référentiel de l’investissement social ? Nos recherches sur la promotion de la parité et de la diversité analysent le glissement des politiques de l’égalité aux politiques de l’identité refondant le modèle républicain sur une quête d’unité par la valorisation des différences. Les politiques d’égalité sont ainsi conditionnées à la performance des différences au sens à la fois de leur théâtralisation d’intérêts et d’identités spécifiques (standing for/acting for) et de leur rentabilité dans une perspective néo-libérale.An Institutionalization of a “Conditional Equality” based on how differences “perform”: Parity, diversity, intersectionality The French contemporary invention of parité and diversité questions the compatibility of the notion of republican equality in a universalist tradition renowned in crisis, the notion of identity in a multicultural context and the notion of utility in the name of virtuous liberalism. In echo of the researches denouncing the French institutionalization of the promotion of parité and diversité as a depoliticization led to an avoidance of the conflicting legal repertoire of anti-discrimination and to an obscuring of the relationships of power, in particular their sexualism and “racialisation”, the purpose is to explore whether this depoliticizing is itself political. We analyze the link between the grammar of injustice and theories of justice in the international debate on intersectionality. How can equality, thought of as a value, an objective and a right, resist being swallowed by the “referential” (normative frame) of social investment? Our researches on the promotion of parité and diversité analyzes the shift from a politics of equality towards a politics of identity basing the republican model on a quest for unity where difference is valued. The politics of equality are so linked to how difference performs. Performance can be understood in two different ways here: firstly, as a mise en scene (standing for/acting for) of specific identities and interests; secondly, from a neo-liberal perspective, as capital gain (increase in value)

On the limits of DTN monitoring

Compared to wired networks, Delay/Disruption Tolerant Networks (DTN) are challenging to monitor due to their lack of infrastructure and the absence of end-to-end paths. This work studies the feasibility, limits and convergence of monitoring such DTNs. More specifically, we focus on the efficient monitoring of intercontact time distribution (ICT) between DTN participants. Our contribution is two-fold. First we propose two schemes to sample data using monitors deployed within the DTN. In particular, we sample and estimate the ICT distribution. Second, we evaluate this scheme over both simulated DTN networks and real DTN traces. Our initial results show that (i) there is a high correlation between the quality of sampling and the sampled mobility type, and (ii) the number and placement of monitors impact the estimation of the ICT distribution of the whole DTN

De la parité à la diversité : entre Deuxième sexe et discrimination seconde

En continuité avec les travaux portant sur la genèse et l'évaluation des lois dites sur la parité, nous questionnerons les enjeux du glissement de la parité à la diversité dans l'espace public français. Nous nous inscrirons ainsi en complémentarité avec les travaux sur l'émergence du terme de diversité, ses usages sociaux et les polémiques concernant sa mesure. Notre hypothèse est que ce glissement participe à l'institutionnalisation d'une égalité sous condition de performance de la différence. Afin de la tester, nous avons croisé l'analyse de rapports, travaux et déclarations sur la diversité avec une enquête qualitative auprès de plus de 150 actrices et acteurs concernés par l'émergence de la diversité comme problème social et politique dans l'espace public : des responsables politiques, institutionnels, religieux, associatifs, syndicalistes, du monde de l'entreprise et des universitaires.In keeping with works on the origins and evaluation of France's ‘parity’ laws, this paper examines the issues involved in the shift in emphasis from ‘parity’ to ‘diversity’ in the French public sphere. The paper builds on, and contributes to, studies of the emergence of the term ‘diversity’, its social meanings and the debates concerning its measurement. Our hypothesis is that this shift helps institutionalise an equality that has become conditional on the performance of difference. To test this hypothesis, the analysis cross-references reports, scholarly studies and declarations on diversity with a qualitative survey of more than 150 public figures who are affected by the emergence of diversity as a social and political problem in the public sphere. The interviewees include politicians, civil servants, academics, and leaders of religious groups, pressure groups, trade unions and businesses

Du gender mainstreaming au paritarisme : genèse d’un concept controversé

La transposition nationale du gender mainstreaming est tout sauf évidente. Sa traduction française par ‘approche intégrée de l’égalité’ puis par ‘paritarisme’ en témoigne, car elle souligne la tendance à occulter, voire à nier, la spécificité de cette notion transnationale. L’analyse de sa genèse, au niveau international et européen, a pour but de souligner la spécificité de ce concept-méthode à la fois valeur et principe d’action. Les controverses autour de cette notion questionnent ainsi les référentiels d’égalité de l’action publique au regard du dilemme de la complémentarité entre actions spécifiques et culture de l’égalité des chances.From gender mainstreaming to paritarisme: the birth of a controversial concept The national transposition of gender mainstreaming is anything but obvious. Its translation into French by “an integrated approach to equality” and then by “paritarisme” indicates this because it underlines the tendency to hide or even deny the specificity of this transnational notion. This analysis of its birth, at an international and European level, aims to emphasise the specificity of this concept-method as both a value and an action principle. The controversies around this idea challenge the references of equality in public action in relation to the dilemma of complementarity between specific actions and the equal opportunities culture.La transposición nacional del mainstreaming de género es todo salvo evidente. Su traducción francesa por “enfoque integrado de la igualdad”, después por “paritarismo” lo muestran, ya que marca la tendencia en ocultar, incluso negar, la especificidad de esta noción transnacional. El análisis de su génesis, a un nivel internacional y europeo, tiene por objetivo realzar la especificidad de este concepto-método, a la vez valor y principio de acción. Las controversias alrededor de esta noción cuestionan los referenciales de igualdad de la acción pública a la vista del dilema de la complementariedad entre acciones específicas y cultura de la igualdad de oportunidades

A generic communication architecture for end to end mobility management in the Internet

The proliferation of laptops, cellular phones, and other mobile computing platforms connected to the Internet has triggered numerous research works into mobile networking. The increasingly dense set of wireless access networks that can be potentially accessed by mobile users open the door to an era of pervasive computing. However, the puzzle of wireless access networks that tends to become the natural access networks to the Internet pushes legacy“wireoriented” communication architectures to their limit. Indeed, there is a critical gap between the increasingly used stream centric multimedia applications and the incapacity of legacy communication stacks to insure the continuity of these multimedia sessions for mobile users. This paper proposes a generic communication architecture (i.e. not dedicated to a specific protocol or technology) that aims to fill the gap between the application layer continuity needs and the discontinuity of the communication service inherent to the physical layer of wireless mobile networks. This paper introduces an end to end communication architecture that preserves efficiently session continuity in the context of mobile and wireless networks. This architecture is mainly based on end to end mechanisms that could be integrated into a new generation reconfigurable transport protocol. The proposed contribution efficiently satisfies mobility requirements such as efficient location management, fast handover, and continuous connection support

On the feasibility of monitoring DTN: Impacts of fine tuning on routing protocols and the user experience

The “machine to machine” communication paradigm will become a central element for mobile networks. This paradigm can be easily constructed by a contact-based network, notably a disruption/delay tolerant networks (DTN). To characterize a DTN, we can use the Inter-contact time among the nodes. The better understanding of inter-contact time (ICT) has practical applications on the tuning of forwarding strategies, and hence in the quality of the User Experience. Nevertheless, the fine tuning of those parameters is tight to a set of assumptions about the regularity of movement or periodicity of patterns in an usually non complete and cumbersome statistical analysis. That is why in a dynamic environment where we cannot assume any previous information the tuning of parameters is usually overestimated. In this work we study how monitoring can help to adapt those parameters to give a better understanding of both natural evolution of the network and non periodical events