January 24, 2008

Is 802.11n Right for You?

The debate over the readiness of 802.11n and whether businesses should adopt or wait is nothing new. Remember when Ethernet was too unpredictable to displace ATM? IP VPNs too unreliable for critical business data? The adoption rate of new technologies is commensurate with the benefits they deliver. 802.11n offers significant performance improvements over existing standards. Still, for most, the benefits must be evaluated in combination with longevity. In other words, few want to deploy a technology that may soon be obsolete – no matter how great the benefit.

802.11n can deliver both performance and longevity. Illustrating market support, the Wi-Fi Alliance has certified over 180 products as 802.11n draft 2.0. Still, the draft status of the standard continues to beg the question of whether the technology is ready. The definition of “standard” includes consistency and interoperability – which are more a function of Wi-Fi certification than IEEE specification. Consider briefly the relationship of the original 802.11b to Wi-Fi, 802.11i to WPA2 and 802.11e to WMM. Businesses don’t deploy an IEEE specification; rather, a standard that guarantees interoperability. The same rings true for 802.11n. While not yet ratified, the 802.11n draft 2.0 has already become a de facto standard thanks to Wi-Fi certification and product development momentum.

Cisco customers are putting this new technology to work today. A large apparel retailer is improving the quality of its warehouse voice-over-wireless implementation by deploying 802.11n. MIMO has improved the call quality of the company’s Cisco wireless IP phones by increasing network reliability and coverage predictability. A large U.S. hospital is deploying 802.11n to ensure consistent connectivity for synchronous patient care applications deployed to mobile computer carts. Without 802.11n, mobile carts were losing connectivity due to coverage holes caused by interference and multipath. Finally, Duke and Western Michigan universities are…deploying 802.11n across campus to support a growing diversity of client devices.

Technology shifts are gradual events that generally take years. With the Wi-Fi Alliance assuring longevity, the adoption timeframes should be determined purely on business need. Assured of investment protection and the performance required for the truly mobile experience, businesses can adopt 802.11n with confidence today.

Posted by Chris Kozup at 05:29 PM Permalink | Comments (5) | TrackBacks (0)

January 07, 2008

The Power of 802.11N

One can barely open a trade rag these days without reading about the arrival of the next generation of wireless standards - 802.11n. It's always exciting when new technology hits the market, especially when that new technology truly lives up to the hype. Of course, as with anything new there's always a bit of misinformation that exists before folks have made it through the learning curve. As I follow the comments of various industry pundits, I'm starting to see a reoccuring theme - misinformation on how to power 802.11n access points.

Power over Ethernet (PoE) has helped many an IT shop save money and improve application availability. Its value extends beyond wireless to include other peripherals, including IP Phones. But arguably, PoE's true calling is in obviating the need for AC power in the ceiling and by default, simplifying and reducing the cost of wireless deployments. However, with the emergence of 802.11n, a new power paradigm is emerging.

Here are the facts:

The 802.3af standard provides up to 12.95 watts at the remote end of the Ethernet cable to power a variety of devices.
To perform at full capacity, dual radio 802.11n access points require greater than 12.95 watts.

Thus, our conclusion:

Currently, 802.3af is not adequate to fully power dual radio 802.11n access points. That is, without some trade offs.

Despite these facts, a number of industry players are claiming to power their dual radio 802.11n access points with standard 802.3af power. While at face value the statement is true, the devil is in the details. The truth is simple. Powering dual radio 802.11n access points with standard 802.3af power will result in a reduction in performance. Here are some different ways in which performance will be impacted:

1. Up to 60% reduction in coverage area (requiring additional access points to cover the same facility)
2. Reduction in throughput (disable transmitters, reduce CPU clock rate, etc.)
3. A loss of services (e.g. security)
4. Limiting to a single radio

What does this mean for the business deploying 802.11n? To realize the full value of their investment, the business must invest in power options that deliver full power to the access point. Options that promise support for standard 802.3af PoE for dual radio 802.11n access points don't come without significant performance implications. IT must assess whether investment in these suboptimal solutions is worth it.

Cisco offers four alternatives that each deliver complete power:

1. Enhanced Power over Ethernet - Cisco has innovated beyond the 802.3af standard to deliver up to 20 watts of power from a single Ethernet port across select members of the Catalyst switch family. This option offers the greatest performance with the lowest operational impact.
2. Power Injector - The Aironet 1250 Series supports power injectors that can deliver adequate power to support full operation.
3. Local AC Power - Access points within proximity of a power outlet can deliver full performance with AC power.
4. Standard 802.3af - The Aironet 1250 Series can fully power a single 802.11n radio with standard 802.3af power. This is ideal for businesses that chose to only deploy on a single frequency (2.4GHz or 5GHz).

Other options such as the nascent 802.3at PoE standard will emerge over the next several quarters.

The next several months promise to be exciting as businesses start to experience the true power of 802.11n. The inadequate power alternatives offered by other providers will leave IT questioning the true performance of 802.11n. Only by treating next generation wireless as an integrated wired and wireless decision can businesses truly unleash the power of business mobility.

Posted by Chris Kozup at 01:21 PM Permalink | Comments (1) | TrackBacks (0)