Buyers of Wi-Fi equipment and systems must be assured that all products have the performance and stability to carry mission-critical applications and data. However, testing of Wi-Fi, or 802.11, devices and systems for performance and stability is a challenge for the industry because of the complexity of the 802.11 protocol. That is compounded by the inherent mobility of the wireless devices and the prevalence of radio frequency interference.

In July 2004, the IEEE formed the IEEE 802.11T Task Group to develop a test specification document, "Recommended Practice for the Evaluation of 802.11 Wireless Performance," expected to be completed in January 2008. By forming the task group, the IEEE has acknowledged the need to provide users with an objective means of evaluating functionality and performance of 802.11 products.

The 802.11T document defines test metrics in the context of use cases. The three principal-use cases are data, latency sensitive and streaming media.

Data

Data applications do not impose critical requirements on a network and include Web downloads, file transfers, file sharing, e-mail and others. Data-oriented traffic is typically transmitted using low priority. Performance test metrics important for data use include throughput vs. range, access-point capacity and access-point throughput per client.

Latency sensitive

Latency-sensitive applications are time-critical, such as VoIP over Wi-Fi. QoS requirements for these applications include limits on voice quality (latency, jitter and packet loss) vs. range, voice quality vs. network load, and voice quality vs. call load and Basic Service Set (BSS).

BSS is a single access-point network, similar to a single cell in the cellular environment. BSS transition is the process of a mobile station roaming from one access point to another.

Streaming media

Streaming-media applications include real-time audio/video streaming, stored content streaming and multicast high-definition television streaming. These applications require the most stringent QoS, including bandwidth and latency guarantees. Performance metrics include video quality (throughput, latency, jitter) vs. range and video quality vs. network load.