2nd International ICST Conference on Wireless Internet

Research Article

Impact of 802.11e EDCA on mixed TCP-based applications

  • @INPROCEEDINGS{10.1145/1234161.1234187,
        author={Marina  Thottan and Michele C. Weigle},
        title={Impact of 802.11e EDCA on mixed TCP-based applications},
        proceedings={2nd International ICST Conference on Wireless Internet},
        keywords={IEEE 802.11e EDCA TCP admission control},
  • Marina Thottan
    Michele C. Weigle
    Year: 2006
    Impact of 802.11e EDCA on mixed TCP-based applications
    DOI: 10.1145/1234161.1234187
Marina Thottan1,*, Michele C. Weigle2,*
  • 1: Center for Networking Research, Bell Laboratories, Murray Hill.
  • 2: Department of Computer Science, Old Dominion University, Norfolk.
*Contact email: marinat@research.bell-labs.com, mweigle@cs.odu.edu


There has been an explosive growth in the use of wireless LANs (WLANs) to support network applications ranging from web-browsing and file-sharing to voice calls. It is difficult to optimally configure WLAN components, such as access points (APs), to meet the quality-of-service requirements of the different applications, as well as ensuring flow-level fairness. Recent work has shown that the widely-deployed IEEE 802.11 MAC Distributed Coordination Function (DCF) is biased against downstream flows. The new IEEE 802.11e standard introduces QoS mechanisms, such as Enhanced Distributed Channel Access (EDCA), that allow this unfairness to be addressed. So far, only limited work has been done to evaluate the impact of these MAC protocols on TCP-based applications. In this paper, through ns-2 simulations, we evaluate the impact of EDCA on TCP application traffic consisting of both long and short-lived TCP flows. We find that the performance of TCP applications is very dependent upon the settings of the EDCA parameters and buffer lengths at the AP. We also show that the performance of the admission control strategy employed depends on the buffer lengths at the AP and the traffic intensity.