A Tolly Group analysis compared the sustainable performance levels of single-channel and emerging multi-channel 802.11 solutions under real-world enterprise conditions. The test is the most comprehensive assessment to date on the impact typical of enterprise usage populations and dynamics on the wireless network, and its findings stand in sharp contrast to current market assumptions. Specifically, the test found today's single-channel networks to be highly vulnerable to sharp drop offs in performance in mixed client and data rate conditions, while multi-channel WLAN solutions achieved and sustained dramatically higher throughput rates, out-performing single-channel solutions by as much as 50-to-1.
Findings specifically revealed that just one minimum data rate client, such as, for example, an 802.11b PDA user at a moderate distance from an AP, brings today's single-channel 802.11g network down from 54 Mbps to close to 1 Mbps. Engim CEO Nick Finamore commented: "Increasingly, WLAN systems must contend with an unpredictable and heterogeneous client environment. At the same time, end users want to add services beyond just data, such as VoWIP. By having multiple channels operating from the same access point, we are able to partition the client traffic to dramatically enhance throughput. As end users deploy new services onto their WLAN system, Engim enables these services to be partitioned intelligently, and implemented on the same WLAN system."
Engim developed the multi-channel access point used in the tests together with Intel, based on the Intel Coyote reference platform. Intel's groundbreaking IXP425 network processor coupled with Engim's EN-3000 multi-channel WLAN chipset enables unprecedented WLAN performance.
Multiple Channel WLAN Infrastructure Enables New Services: Engim's multi-channel processors are the foundation for multi-channel wireless LAN access points that simultaneously support and optimize an array of new user services such as voice, security, video, and location detection from a single, far more efficient platform. These multi-service APs, deployed strategically throughout the enterprise network, provide the performance and stability to help drive wide-scale enterprise migration to wireless networks.
Tolly Group engineers compared the aggregate throughput of several popular current single-channel access points and a prototype multi-channel access point. To emulate real-world user configurations, a mix of .11b and .11g clients were associated to the access points at various distances and data rates. Eight client combinations were tested that reflect typical enterprise WLAN configurations, and the potential impacts of RF anomalies and environmental noise were eliminated.
The results were dramatic, and showed that APs based on Engim multi-channel WLAN silicon consistently performed far higher than any of the three commercially-available, single-channel APs tested. In most scenarios, the multi-channel AP results were 10 to 20 times greater than those of single-channel APs, and in some tests, the multi-channel AP delivered approximately 50 times greater throughput than single-channel solutions.
Kevin Tolly, President and CEO of The Tolly Group, noted: "The situation is potentially a significant problem for the enterprise: just one minimum rate association client can substantially reduce the channel's capacity. This means that just one 802.11b-only user walking through a 54 Mbps network slows the entire network, including users and voice applications, to mere single digit Mbps, and scanners sharing the network with data devices will have the same effect. Considering the importance of consistent performance to emerging applications such as Voice over Wireless IP, the case for multi-channel Wi-Fi becomes a compelling advantage for users and vendors."
Test results demonstrate the Enterprise impact of the use of multiple 802.11 channels and Engim's Intelligent Channel Association (ICA), which maximizes system throughput by intelligently associating clients to strategic channels based on the individual client's signal integrity, 802.11 standard type, traffic type, and traffic load. The approach actively prevents the bottlenecks that now commonly plague single-channel wireless networks, when slower data rate users reduce the throughput of all clients on the network. The combination of multiple channels and ICA provides substantial performance gains that are particularly important to ensure the throughput, stability and Quality of Service of performance-sensitive applications such as VoWLAN (Voice over Wireless LAN).
The Tolly Group is an independent testing and strategic consulting organization recognized worldwide for its expertise in assessing leading-edge technologies.
Engim is a fabless developer of wireless system-on-chip technology.
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