An Experimental Testbed and Methodology for Characterizing IEEE 802.11 Network Cards
WOWMOM '06 Proceedings of the 2006 International Symposium on on World of Wireless, Mobile and Multimedia Networks
On the feasibility of IEEE 802.11 multi-channel multi-hop mesh networks
Computer Communications
Validation of the IEEE 802.11 MAC model in the ns3 simulator using the EXTREME testbed
Proceedings of the 3rd International ICST Conference on Simulation Tools and Techniques
An emulation tool for PlanetLab
Computer Communications
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The IEEE 802.11 DCF protocol is known to be fair in termsof long-term resource repartition among the contending stations.However, when considering real scenarios, where commercial802.11 cards interact, very unpredictable as well as sometimessurprising behaviors emerge. Motivation of this paper is toinvestigate the reasons of the very evident disagreement betweenthe theoretical IEEE 802.11 DCF protocol models and its practical implementations. In particular, we try to characterize the card behavior not only in terms of perceived throughput, but also in terms of low-level channel access operations. In fact, the simple throughput analysis does not allow to identify what affecting parameters, both in terms of transceiversarchitectures and MAC layer deployments, determine the performancedifferentiation among the cards. To this purpose, we implemented a tunable DCF network card, inwhich all MAC parameters are programmable and all the basebandsignals are available, and we used this card as a probe instrument.We registered the low-level access operations of commercial cardsin terms of access times revelead by the carrier sense function of our probe card. By comparing these times, we surprisingly provedthat the most evident performance differences are not due to PHYlayer issues, but to the MAC implementations,which often seemto do not respect the standard specifications.