March 2005
March 2005
Tom Alexander
VeriWave, Inc.
Slide 1 Tom Alexander

March 2005
• Task group within the IEEE 802.11 Wireless LANs group
• Formally created in August 2004 to recommend methods for testing performance of 802.11 devices and systems
– Goal: establish a common framework, terminology and methodology for the 802.11 Wireless LAN industry
Slide 2 Tom Alexander

March 2005
• Scope and purpose
– Official scope: “to provide a set of performance metrics, measurement methodologies, and test conditions to enable measuring and predicting the performance of 802.11 WLAN devices and networks at the component and application level”
– Official purpose: “to enable testing, comparison, and deployment planning of 802.11 WLAN devices based on a common and accepted set of performance metrics, measurement methodologies and test conditions”
• Output will be IEEE 802.11.2, a “Recommended Practice”
– Uses the word “should”
Slide 3 Tom Alexander

March 2005
• Officers
– Chair: Charles Wright, Azimuth Systems
– Technical Editor: Tom Alexander, VeriWave Inc
– Secretary: none yet
• About 15 – 20 active members
– Sometimes up to 40 people attend
• Involvement from a broad cross-section of the WLAN industry
– System and chipset vendors: Dell, Intel, Broadcom, AMD, Atheros, …
– Test equipment vendors: Spirent, Azimuth, Rohde & Schwarz, VeriWave, …
– Installation tools & services vendors: Wireless Valley, …
– Users: Microsoft, UBC, UNH-IOL, …
– And some just plain interested folks
• Activity
– Meets during every 802.11 interim or Plenary for about 10 – 16 hours
– Weekly teleconferences (Thursday mornings, 9AM PST)
– Ad-hoc teleconferences
Slide 4 Tom Alexander

March 2005
•
Scope and framework
– What kind of metrics? What sort of approach to measurement? What layer(s) do we include?
– Diverse group; these discussions help build common understanding
– General consensus on some key issues
• Both open-air and conducted metrics should be specified
• Metrics should be somehow tied to end-user experience
• Etc.
•
Draft structure
– Proposed templates for the overall draft and for individual measurement descriptions have been created, plus proposals for the organization of the standard
•
Terminology
– Key discussion point in group to date (e.g., “What is a metric? What does
‘controlled environment’ imply?)
• Lots of “this is how we did it” and “this is how we should do it” presentations
– Very useful in assessing what is possible and what is not
– Wireless measurement methodologies differ somewhat from wired
Slide 5 Tom Alexander

March 2005
• Convergence on some basic terminology
– Examples: ‘controlled test environment’, ‘conducted test’, ‘overthe-air test’, ‘interference’, etc.
– Most of these are specific to wireless testing (as opposed to benchmarking in general)
• Not much disagreement (yet!) on terms such as latency, throughput, loss, delay, etc.
• Adoption of ground rules before voting on formal proposals
– Requirements for a proposal to be considered “complete”
– Format and content of formal metrics & methodology proposals
• Timeline for first draft standard: uncertain at the moment
Slide 6 Tom Alexander

March 2005
• The 802.11 document server
– www.802wirelessworld.com – 802.11 document server with 802.11T contributions
– Examples of interesting contributions:
• # 11-04-1160-00-000t Enabling Prediction of Wireless Performance
• # 11-04-1202-00-000t Proposed Metrics and TGT Call to Action
• # 11-04-1222-01-000t Measurement Methodology Proposal Based on
Approved Framework
• # 11-05-1582-00-000t Environment and Metrics: Laboratory vs. Real-world
• # 11-05-0002-00-000t Proposed TGT Document Structure
• # 11-05-0004-01-000t TGT Terminology and Concepts
• The 802.11T reflector
• March 802.11 Plenary
– March 14th to 18th, Atlanta, GA
Slide 7 Tom Alexander