Wireless Performance Prediction (WPP) - Addressing End-User Issues doc.: IEEE 802.11-00/457 November 2003 Wireless Performance Prediction (WPP) - Addressing End-User Issues Tom Alexander tom@veriwave.com VeriWave, Inc. Tom Alexander, VeriWave

Outline Common end-user issues with 802.11 WLANs November 2003 Outline Common end-user issues with 802.11 WLANs What WPP can do to address these issues Tom Alexander, VeriWave

Common End-User Issues doc.: IEEE 802.11-00/457 November 2003 Common End-User Issues Early-adopter experience with WLANs usually positive Lots of anecdotal problems – but users generally happy However, corporate users have been conditioned by over a decade of wired LANs Relative to wired LANs, wireless LANs today: Variable and unpredictable coverage Indeterminate capacity and coverage Interoperation problems Susceptibility to outside interference Widespread corporate adoption will make these issues more visible Current environment of folklore (e.g., people who can “see RF”) won’t go very far Tom Alexander, VeriWave

Unpredictable Coverage and Capacity doc.: IEEE 802.11-00/457 November 2003 Unpredictable Coverage and Capacity WLAN coverage significantly affected by environment Often changes over time Walk-around site surveys normally done to address this Expensive, but new equipment/technology starting to address Directive antennas make this issue worse Deterministic capacity is a bigger problem Common question: "How much bandwidth should I be getting?” Also: How many clients can be assigned to a given BSS? Exactly what improvement can be obtained with 802.11g? 802.11a? Nobody seems to know … No standard metrics or test methods for capacity 802.11b WLANs do NOT provide 11 Mb/s of throughput! Variation of throughput with client loading unknown Tom Alexander, VeriWave

Unreliable / Non-conformant Equipment doc.: IEEE 802.11-00/457 November 2003 Unreliable / Non-conformant Equipment Equipment reliability issues in WLANs APs locking up, client driver issues, etc. AP reliability issues quite difficult to handle Inconvenient locations - safety and access problems 802.11 standards conformance is also an issue Adherence to standards is rather spotty Issues for future protocols (e.g., EDCA) No standards for WLAN equipment reliability and conformance Need to develop test methods and benchmarks Tom Alexander, VeriWave

Interoperation, Interference, Security doc.: IEEE 802.11-00/457 November 2003 Interoperation, Interference, Security These are some of the biggest problems Interoperation is a significant end-user problem Sometimes equipment from same vendor doesn't interoperate Standards conformance issues Interference issues are widespread Installers carry spectrum analyzers into end-user sites Frequently interference occurs from other 802.11 equipment e.g., due to improper power settings Problem will get worse over time as ISM bands fill up Security is a well-known problem Lots of publicity, hence many solutions coming on line End-user apathy probably biggest concern Need significant enhancement of metrics for interoperation and interference resistance Tom Alexander, VeriWave

Need to define repeatable metrics and tests for: doc.: IEEE 802.11-00/457 November 2003 Conclusions Need to define repeatable metrics and tests for: Conformance Performance and capacity Interoperability Resistance to interference Security Need to ensure that metrics and methods are correlated to end-user experience Users need to be able to rely on metrics and benchmarks to predict the installed performance of WLAN equipment Need to ensure that metrics & methods accommodate all types of end-user WLAN equipment The standard and the industry is continuously evolving Tom Alexander, VeriWave