Interplay between security providers, consumers, and attackers: a weighted congestion game approach

Network users can choose among different security solutions to protect their data. Those solutions are offered by competing providers, with possibly different performance and price levels. In this paper, we model the interactions among users as a noncooperative game, with a negative externality coming from the fact that attackers target popular systems to maximize their expected gain. Using a nonatomic weighted congestion game model for user interactions, we prove the existence and uniqueness of a user equilibrium, compute the corresponding Price of Anarchy, that is the loss of efficiency due to user selfishness, and investigate some consequences for the (higher-level) pricing game played by security providers.Game theory;Weighted games; Security

Managing a peer-to-peer backup system: does imposed fairness socially outperform a revenue-driven monopoly ?

International audienceWe study a peer-to-peer backup system, where users offer some of their storage space to provide service for the others. The economic model for such a system is different from the ones applicable to peer-to-peer file sharing systems, since the storage capacity is a private good here. We study two mechanisms aimed at incentivizing users to offer some of their capacity: a price-based scheme (here a revenue-driven monopoly) and a more classical symmetric scheme (imposing users to contribute to the service at least as much as use it). We compare the outcomes of such mechanisms to the socially optimal situation that could be attained if users were not selfish, and show that depending on user heterogeneity, a revenue maximizing monopoly can be a worse or a better (in terms of social welfare) way to manage the system than a symmetric scheme

Overlaying Delay-Tolerant Service using SDN

International audienceTelecommunication networks are generally dimensioned to provide services with small delays and high throughput during peak-periods. Due to the sizable difference in the network utilization between the peak and off-peak periods as well as the requirements of robust performance in face of both traffic burstiness and various types of network failures, these networks are significantly over-dimensioned for the average network loads. In this paper, we propose to use this extra capacity for supporting a deferrable traffic class with some guarantees on its end-to-end delays. Using the Software-Defined Networking (SDN) capabilities for controlling the network ingress rates of the deferrable traffic class in real time, we ensure that such a service would remain transparent to existing delay-sensitive traffic. To estimate the available capacities for the deferrable service, we analyze large deviations for the proposed traffic model. Starting from an initial network designed for delay-sensitive traffic, one can readily "overlay" a new network for the deferrable service at no extra cost. This overlaid network has the same topology as the original one, and its link capacities can be directly computed from the characteristics of the existing traffic, the original link capacities, and the end-to-end delay tolerances

Road-side units operators in competition: A game-theoretical approach

International audienceWe study the interactions among Internet providers in vehicular networks which offer access to commuters via road side units (RSUs). Namely, we propose a game-theoretical framework to model the competition on prices between vehicular Internet providers to capture the largest amount of users, thus selfishly maximizing the revenues. The equilibria of the aforementioned game are characterized under different mobile traffic conditions, RSU capabilities and users requirements and expectations. In particular, we also consider in the analysis the case where mobile users modify the price they accept to pay for the access as the likeliness of finding an access solution decreases. Our game-theoretical analysis gives insights on the outcomes of the competition between vehicular Internet providers, further highlighting some counter-intuitive behaviors; as an example, comparing with the case when users have constant price valuation over time, having users inclined to increasing their "acceptable" price may force vehicle Internet providers to charge lower prices due to competition

Optimization of link adaptation and HARQ schemes for multicast in high speed cellular networks

International audienceThis paper targets multicast transmission where the same data is destined to many users simultaneously. Although multicast allows bandwidth saving, it prevents a precise link adaptation over radio links. Indeed, users are subject to the same bitrate despite their different and variable radio conditions. Neither operators nor 3GPP standard offer solutions to support link adaptation in a multicast scenario. In this context, we propose different solutions. We compare conservative and aggressive schemes by computing the resulting throughput performance. For this purpose, we propose a model to compute the average number of retransmissions. We also study the mapping between the reported SNR and the packet sizes in HSDPA systems. We show that the existing mapping offers the best performance for unicast but cuts down the throughput in a multicast scenario. Then, we propose a convenient mapping for multicast, namely shifted mapping. Despite the better precision of this solution, the resulting gain remains marginal

Competition between wireless service providers sharing a radio resource

radio resourc

Impact of Content Delivery Networks on service and content innovation

International audienceContent Delivery Networks (CDNs) are major actors of the current telecommunication ecosystem. Our goal in this paper is to study their impact on other actors of the supply chain, especially on content innovation which is a key concern in the network neutrality debate where CDNs' role seems forgotten. Our findings indicate that vertically integrating a CDN helps Internet Service Providers (ISPs) collect fees from Content Providers (CPs), hence circumventing the interdiction of side payments coming from net-neutrality rules. However, this outcome is socially much better in terms of user quality and innovation fostering than having separate actors providing the access and CDN services: in the latter case double marginalization (both ISP and CDN trying to get some value from the supply chain) leads to suboptimal investments in CDN storage capacities and higher prices for CPs, resulting in reduced innovation

Adword auction bidding strategies of budget-limited advertisers on competing search engines

International audienceThe economic stakes of advertising on the Internet -and in particular, of auctions for keywords in search engines- are enormous and still increasing. We focus in this paper on situations where bidders (advertisers) on sponsored search auction systems have a limited budget, so that they may not be able to afford to participate in all auctions. Using a game-theoretical model of the strategic interactions among advertisers, we analyze the equilibrium strategies in terms of bidding frequencies, in the case of one monopoly search engine and when two search engines are in competition. Our results exhibit the importance for search engines to develop their attractiveness to customers, due to the impact this has on auction revenues

Pricing the Internet with Multi-Bid Auctions

Usage-based or congestion-based charging schemes have been regarded as a relevant way to control congestion and to differentiate services among users in telecommunication networks; auctioning for bandwidth appears as one of several possibilities. In a previous work, the authors designed a multi-bid auction scheme where users compete for bandwidth at a link by submitting several couples (amount of bandwidth asked, associated unit price) so that the link allocates the bandwidth and computes the charge according to the second price principle. They showed that incentive compatibility and efficiency among other properties are verified. We propose in the present paper to extend this scheme to the case of a network, by using the properties/assumptions that the backbone network is overprovisionned and the access networks have a tree structure