ABSTRACT
Wireless LAN (WLAN) market consists of IEEE 802.11 MAC standard conformant devices (e.g., access points (APs), client adapters) from multiple vendors. Certain third party certifications such as those specified by the Wi-Fi alliance have been widely used by vendors to ensure basic conformance to the 802.11 standard, thus leading to the expectation that the available devices exhibit identical MAC level behavior. In this paper, however, we present what we believe to be the first ever set of experimental results that highlight the fact that WLAN devices from different vendors in the market can have heterogeneous MAC level behavior. Specifically, we demonstrate with examples and data that in certain cases, devices may not be conformant with the 802.11 standard while in other cases, they may differ in significant details that are not a part of mandatory specifications of the standard. We argue that heterogeneous MAC implementations can adversely impact WLAN operations leading to unfair bandwidth allocation, potential break-down of related MAC functionality and difficulties in provisioning the capacity of a WLAN. However, on the positive side, MAC level heterogeneity can be useful in applications such as vendor/model level device fingerprinting.
- Cisco Systems Inc., www.cisco.com.Google Scholar
- D-link Systems Inc., www.dlink.com.Google Scholar
- Intel Corporation, www.intel.com.Google Scholar
- Netgear Inc., www.netgear.com.Google Scholar
- 3Com Inc., www.3com.com.Google Scholar
- Proxim Inc., www.proxim.com.Google Scholar
- IEEE 802.11 Standard, Wireless LAN Medium Access Control (MAC) and Physical layer (PHY) Specifications, 1999.Google Scholar
- Wi-Fi Alliance, www.wifialliance.comGoogle Scholar
- Wi-Fi CERTIFIED®: The Safe Buy, October 5 2004, http://www.wi-fi.org/white_papers/whitepaper-100504-wifisafebuy/.Google Scholar
- Hagen Woesner et al., Modified backoff algorithms for DFWMAC's distributed coordination function, Proc. of 2nd ITG Fachtagung Mobile Kommunikation '95, Neu-Ulm, Germany, September 1995.Google Scholar
- Byung-Jae Kwak et al., "Performance Analysis of Exponential Backoff", IEEE/ACM Transactions on Networking, Vol 13, Issue 2, April 2005 Google ScholarDigital Library
- Prism Wireless LAN, http://www.intersil.com/globespanvirata/.Google Scholar
- G. Bianchi, "Performance Analysis of the IEEE 802.11 Distributed Coordination Function", IEEE Journal on Selected Areas in Communications, Vol 18, No. 3, March 2000. Google ScholarDigital Library
- F. Cali, M. Conti, E. Gregori, "IEEE 802.11 Wireless LAN: Capacity analysis and protocol enhancement", In Proc. of Infocom' 98, San Francisco, USA, 1998.Google Scholar
- Ping Chung Ng et al., "Experimental Study of Hidde-Node Problem in IEEE802.11 Wireless Networks", Poster Presentation, SIGCOMM 2005, PA, USAGoogle Scholar
- Joshua Wright, "Detecting Wireless LAN MAC Address Spoofing", http://www.polarcove.com/whitepapers/detectwireless.pdf.Google Scholar
- IEEE 802.11e Standard, Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements, 2005, http://grouper.ieee.org/groups/802/11/.Google Scholar
Index Terms
- An empirical analysis of heterogeneity in IEEE 802.11 MAC protocol implementations and its implications
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