Drakkar

Gabriele Romaniello

Gabriele Romaniello — 2012-01-06T10:15:58Z

PhD thesis

- Doctorants

Antonio De Domenico

Antonio De Domenico — 2012-01-06T10:14:18Z

PhD thesis

- Alumni

Giorgio Corbellini

Giorgio Corbellini — 2012-01-06T10:11:14Z

PhD thesis

- Alumni

Mustapha Bilal

Mustapha Bilal — 2012-01-06T10:07:28Z

PhD thesis

- Doctorants

Jun-Young Bae

Jun-Young Bae — 2012-01-06T10:05:14Z

PhD thesis : security in wireless sensor networks

- Doctorants

Connectivity in Multi-Channel Multi-Interface Wireless Mesh Networks

Andrzej Duda, Carina Teixeira de Oliveira, Fabrice Theoleyre — 2011-07-05T08:00:00Z

We can improve the performance of wireless mesh networks by using multiple interfaces tuned to non-overlapping channels. A Channel and Interface Assignment (CIA) decides when to switch interfaces and which channel to use. Surprisingly, the impact of CIAs on connectivity has received little attention so far. In this paper, we present a comparison and performance evaluation of the existing CIA strategies addressing the connectivity issues : network topology, density of connections, and neighbor discovery. The results presented in this paper provide guidelines for network designers in planning multi-channel multi-interface network deployments.

Broadcast Strategies with Probabilistic Delivery Guarantee in Multi-Channel Multi-Interface Wireless Mesh Networks

Andrzej Duda, Carina Teixeira de Oliveira, Fabrice Theoleyre — 2011-06-30T08:00:00Z

- Autres

Broadcast Strategies with Probabilistic Delivery Guarantee in Multi-Channel Multi-Interface Wireless Mesh Networks

Andrzej Duda, Carina Teixeira de Oliveira, Fabrice Theoleyre — 2011-06-12T08:00:00Z

Multi-channel multi-interface Wireless Mesh Networks permit to spread the load across orthogonal channels to improve network capacity. Although broadcast is vital for many layer-3 protocols, proposals for taking advantage of multiple channels mostly focus on unicast transmissions. In this paper, we propose broadcast algorithms that fit any channel and interface assignment strategy. They guarantee that a broadcast packet is delivered with a minimum probability to all neighbors. Our simulations show that the proposed algorithms efficiently limit the overhead.

Available online

@inproceedings{teixeira-med-hoc-net2011, author = {Teixeira de Oliveira, Carina and Theoleyre, Fabrice and Duda, Andrzej}, title = {Broadcast Strategies with Probabilistic Delivery Guarantee in Multi-Channel Multi-Interface Wireless Mesh Networks}, booktitle = {IEEE IFIP Annual Mediterranean Ad Hoc Networking Workshop (Med-Hoc-Net)}, address = {Favignana Island, Sicily, Italy}, month = Jun # {~12--15,}, year = 2011 }

Evaluation de la stratégie d'assignation de canaux pour IEEE 802.11s

Andrzej Duda, Carina Teixeira de Oliveira, Fabrice Theoleyre — 2011-05-23T08:00:00Z

IEEE 802.11s propose une couche MAC unifiée pour gérer un réseau maillé multicanal multiradio. Le protocole est simple puisqu'il repose sur une assignation statique des canaux, menant à une assignation de type canal commun (la k° interface utilise le canal k). Nous proposons ici de quantifier l'impact de ces choix techniques sur la capacité du réseau, critère névralgique de performance dans les réseaux maillés. Nous proposons une formulation en PLNE générique permettant d'évaluer la capacité de IEEE 802.11s et donnant des pistes pour l'améliorer.

@inproceedings{teixeira-algotel2011, author = {Teixeira de Oliveira, Carina and Theoleyre, Fabrice and Duda, Andrzej}, title = {Evaluation de la stratégie d'assignation de canaux pour IEEE 802.11s}, booktitle = {13es Rencontres Francophones sur les Aspects Algorithmiques des Télécommunications (Algotel)}, address = {Cap Estérel, France}, month = May # {~23--26,}, year = 2011, x-international-audience = {no}, }

Two-way TCP Connections : Old Problem, New Insight

Andrzej Duda, Martin Heusse — 2011-04-01T15:26:00Z

Available on line

Many papers explain the drop of download performance when two TCP connections in opposite directions share a common bottleneck link by ACK compression, the phenomenon in which download ACKs arrive in bursts so that TCP self clocking breaks. Efficient mechanisms to cope with the performance problem exist and we do not consider proposing yet another solution. We rather thoroughly analyze the interactions between connections and show that actually ACK compression only arises in a perfectly symmetrical setup and it has little impact on performance. We provide a different explanation of the interactions — data pendulum, a core phenomenon that we analyze in this paper. In the data pendulum effect, data and ACK segments alternately fill only one of the link buffers (on the upload or download side) at a time, but almost never both of them. We analyze the effect in the case in which buffers are structured as arrays of bytes and derive an expression for the ratio between the download and upload throughput. Simulation results and measurements confirm our analysis and show how appropriate buffer sizing alleviates performance degradation. We also consider the case of buffers structured as arrays of packets and show that it amplifies the effects of data pendulum.

@Article { Heusse:2011ws, author = {Heusse, Martin and Merritt, Sears A and Brown, Timothy X and Duda, Andrzej}, title = {{T}wo-way {TCP} {C}onnections: {O}ld {P}roblem, {N}ew {I}nsight}, journal = {{ACM} {C}omputer {C}ommunication {R}eview}, year = {2011}, month = {apr} }