Inferring Queue State by Measuring Delay in a WiFi Network
Packet round trip time is a quantity that is easy to measure for end hosts and applications. In many wired networks, the round trip has been exploited for purposes such as congestion control and bandwidth measurement because of relatively simple relationships between buffer occupancy and drain time. In 802.11 networks, the buffer drain times show considerable variability due to the random nature of the MAC service. We examine some of the problems faced when using round-trip-time-based queue estimates in these networks, particularly in relation to congestion control.
KeywordsQueue Length Congestion Control Busy Period Measuring Delay Buffer Occupancy
Unable to display preview. Download preview PDF.
- 1.Multiband Atheros driver for WiFi (MADWiFi) r1645 version, http://sourceforge.net/projects/madwifi/
- 2.Soekris engineering, http://www.soekris.com/
- 4.Dangerfield, I., Malone, D., Leith, D.J.: Experimental evaluation of 802.11e EDCA for enhanced voice over WLAN performance. In: Proc. WiNMee (2006)Google Scholar
- 5.Franceschinis, M., Mellia, M., Meo, M., Munafo, M.: Measuring TCP over WiFi: A real case. In: WiNMee (April 2005)Google Scholar
- 6.IEEE. Wirless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, IEEE std 802.11-1997 edition (1997)Google Scholar
- 7.Jacobson, V.: Pathchar - a tool to infer characteristics of internet paths. MSRI (April 1997)Google Scholar
- 8.McCullagh, G.: Exploring delay-based tcp congestion control. Masters Thesis (2008)Google Scholar
- 9.Ng, A.C.H., Malone, D., Leith, D.J.: Experimental evaluation of TCP performance and fairness in an 802.11e test-bed. In: ACM SIGCOMM Workshops (2005)Google Scholar
- 10.Rizzo, L.: Dummynet: a simple approach to the evaluation of network protocols. ACM/SIGCOMM Computer Communication Review 27(1) (1997)Google Scholar
- 11.Sundaram, N., Conner, W.S., Rangarajan, A.: Estimation of bandwidth in bridged home networks. In: Proc. WiNMee (2007)Google Scholar
- 12.Tan, K., Song, J., Zhang, Q., Sridharan, M.: A compound tcp approach for high-speed and long distance networks. In: INFOCOM (2006)Google Scholar