Abstract

The book presents mechanisms, protocols, and system architectures to achieve end-to-end Quality-of-Service (QoS) over heterogeneous wired/wireless networks in the Internet. Particular focus is on measurement techniques, traffic engineering mechanisms and protocols, signalling protocols as well as transport protocol extensions to support fairness and QoS. It shows how those mechanisms and protocols can be combined into a comprehensive end-to-end QoS architecture to support QoS in the Internet over heterogeneous wired/wireless access networks. Finally, techniques for evaluation of QoS mechanisms such as simulation and emulation are presented. The book is aimed at graduate and post-graduate students in Computer Science or Electrical Engineering with focus in data communications and networking as well as for professionals working in this area.

Abstract

International audience; Recent research have considered aeronautical ad hoc networks as a possible mean for future aeronautical communications. By introducing inter- aircraft links, they are supposed to become an alternative to existing solutions based on direct air- ground or satellite links. In this paper, we propose the use of asynchronous Code Division Multiple Access (CDMA) in aeronautical ad hoc networks. We then present a simulation model developed with OPNET Modeler that estimates the impact of Multiple Access Interference (MAI) on packets delivery. Finally, we give the results of some simulations made with an ATC/AOC traffic model, and with real aircraft positions over the French sky.

Abstract

National audience; This research paper proposes IEEE802.3az incorporated green algorithmic schemes on the software defined networking-based segment routing (SDN-based SR) centralized network. The proposed schemes are the green (i.e. the EAGER and CARE metrics) SDN-based SR networks with and without traffic engineering (TE) tunneling. Green metrics extend the IEEE 802.3az energy saving to the whole network, while tunneling avoids the load sharing mechanism included in the segment routing that is not convenient for energy saving purpose. The findings of emulation revealed that the energy efficiency under the EAGER-tunneling strategy is comparable to the conventional metric with TE tunneling, and the saving realized under the CARE-tunneling scheme is twofold in comparison with the LEGACY-tunneling strategy. Meanwhile, the energy saving performance achieved with all three metrics under TE non-tunneling was inferior to those with tunneling. Nonetheless, the lower end-to-end delay and lower maximum link utilization (MLU) were achievable with the non-tunneling strategy.

Abstract

This paper presents the PhD work conducted by Na TAO. The director of this thesis is Professor Michel BOUSQUET. The study is supervised by Alain PIROVANO and Jose RADZIK. This PhD work has started January 2006 and will end in December 2008. Two concurrent satellite systems are presently proposed for in-flight entertainment (IFE) communications, thus demonstrating the capability of satellites to provide multimedia access to users on board airplanes. At the same time, an increasing interest for the use of satellite communications for air traffic control has been motivated by the increasing load of traditional radio links, mainly in the VHF band. However, the development of a dedicated satellite system for ATC (Air Traffic Control) and ATN (Aeronautical Telecommunication Network) seems to be a long-term perspective. The objective of the presented system design is to provide both passenger application traffic (Internet, GSM) access and a high-reliability channel for aeronautical applications using the same satellite links. Due to the constraints in capacity and radio bandwidth allocation, very high frequencies (above 20 GHz) are considered here. The corresponding design implications for the air interface are taken into account and access performances are derived using a dedicated simulation model. Some preliminary results are shown in this paper to demonstrate the technical feasibility of such system design with increased capacity, more details and the open issues will be studied in the future of the thesis research.

Abstract

International audience; This article introduces a simple and effective methodology to determine the level of congestion in a network with an ECN-like marking scheme. The purpose of the ECN bit is to notify TCP sources of an imminent congestion in order to react before losses occur. However, ECN is a binary indicator which does not reflect the congestion level (i.e. the percentage of queued packets) of the bottleneck, thus preventing any adapted reaction. In this study, we use a counter in place of the traditional ECN marking scheme to assess the number of times a packet has crossed a congested router. Thanks to this simple counter, we drive a statistical analysis to accurately estimate the congestion level of each router on a network path. We detail in this paper an analytical method validated by simulations which demonstrate the feasibility and the accuracy of the concept proposed and illustrate its use in a realistic scenario. We conclude this paper with possible applications and expected future work.

Abstract

International audience; This paper studies and analyses the benefits of favouring the transfer of packets of a TCP flow over a best-effort network. Specifically, we aim at studying whether we could improve the pace of short data request, such as HTTP request, by giving a high priority to TCP packets that are not previously enqueued inside a core router. Following the idea that long-lived TCP flows greatly increase the routing queue delay, the motivation of this work is to minimise the impact in terms of delay, introduced by long-lived TCP flows over short TCP flows. Thus, this forwarding scheme avoids to delay packets that do not belong to a flow already enqueued inside a router in order to avoid delay penalty to short flow. We define metrics to study the behaviour of such forwarding scheme and run several experiments over a complex and realistic topology. The results obtained present interesting and unexpected property of this forwarding scheme where not only short TCP flows take benefit of such routing mechanism.