IMDEA Networks Institute Publications Repository

Impact of Transient CSMA/CA Access Delays on Active Bandwidth Measurements

Portoles-Comeras, Marc and Cabellos-Aparicio, Albert and Banchs, Albert and Mangues-Bafalluy, Josep and Domingo-Pascual, Jordi (2009) Impact of Transient CSMA/CA Access Delays on Active Bandwidth Measurements. In: The 9th ACM Conference on Internet Measurement Conference (ACM IMC 2009), 4 – 6 November, 2009, Chicago, Illinois, USA.

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WLAN devices based on CSMA/CA access schemes have become a fundamental component of network deployments. In such wireless scenarios, traditional networking applications, tools, and protocols, with their built-in measurement techniques, are usually run unchanged. However, their actual interaction with the dynamics of underlying wireless systems is not yet fully understood. A relevant example of such built-in techniques is bandwidth measurement. When considering WLAN environments, various preliminary studies have shown that the application of results obtained in wired setups is not straightforward. Indeed, the contention for medium sharing among multiple users inherent to CSMA/CA access schemes has remarkable consequences on the behavior of and results obtained by bandwidth measurement techniques. In this paper, we focus on evaluating the effect of CSMA/CA-based contention on active bandwidth measurement techniques. As a result, it presents the rate response curve in steady state of a system with both FIFO and CSMA/CA-based contending cross-traffic. We also find out that the distribution of access delay shows a transient regime before reaching a stationary state. The duration of such transient regime is characterized and bounded. We also show how dispersion-based measurements that use a short number of probing packets are biased measurements of the achievable throughput, the origin of this bias lying on the transient detected in the access delay of probing packets. Overall, the results presented in this paper have several consequences that are expected to influence the design of bandwidth measurement tools as well as to better understand the results obtained with them in CSMA/CA links.

Item Type: Conference or Workshop Papers (Paper)
Uncontrolled Keywords: Bandwidth measurements, Wireless, CSMA/CA, Achievable Throughput
Subjects: Q Science > Q Science (General)
Q Science > QA Mathematics > QA75 Electronic computers. Computer science
T Technology > T Technology (General)
T Technology > TK Electrical engineering. Electronics Nuclear engineering
Divisions: Faculty of Engineering, Science and Mathematics > School of Electronics and Computer Science
Depositing User: Systems Ad Systems Administrator
Date Deposited: 14 Feb 2012 13:20
Last Modified: 15 Dec 2016 10:41

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