N for iNevitable

By Phil Belanger

May 04, 2007

Novarum's analysts begin a series focused on 802.11n, examining the new technology’s promised improvements.

The next generation of wireless local area network standards is on the path to final approval by the IEEE. It is a complex standard – years in the making – and now initial implementations compatible with the nascent standard are starting to appear in real products. Why should we care?

First, it is really a good standard – you will want it. IEEE 802.11n is the fourth generation of wireless LANs and incorporates state-of-the-art technologies available for the first time in wireless networks of any scale. It’s much more than a speed upgrade. It changes everything in the standard - radios, antennas, and medium access protocol. You will want it - the only questions are when and how.

Irresistible speed. 802.11n will deliver data rates up to eight times faster than 802.11g products - though likely only available in stages: three times better now, and three times better later with more advanced products. If you are a conservative and stick to the crowded 2.4 GHz band (along with those nasty microwave ovens), 11n will increase the 20 Megabits per second (Mbps) useful throughput we get from 802.11g up to as much as 80 Mbps. However, if you take the plunge and move to 5 GHz, 11n can deliver as much as 160 Mbps of useful throughput. High-end products like Apple’s new 11n Airport Extreme deliver the best performance by using both 2.4 GHz and 5 GHz to get the most out the new technology.

Delicious range. 802.11n doubles the range over the previous generation, and actually likes obstructions. Clever use of simultaneous transmission from multiple antennas, much like multi-core CPUs, leverages radio parallelism to improve range and throughput. The real win from this range increase is the more practical use of the 5 GHz band. 802.11a products offer 5 GHz operation, but just don’t have the muscle to deliver useful range in many cases. 11n’s improved range will make the 5 GHz band the go-to place for high performance wireless.

Seductive capacity. The untold story. The combination of technologies in 11n has a breakthrough effect on overall wireless capacity. While less important in our homes than in our businesses, the multiplier effect of increased speed, increased range and practical use of the 5 GHz band yields potentially 7 gigabits of raw capacity for 11n networks. By contrast, standard 11g WLANs operating in the 2.4 GHz band deliver 162 megabits of raw capacity at best.

Improved security. WLAN security – if deployed correctly – is a solved problem. Unfortunately, there is still a lot of legacy Wi-Fi equipment deployed with older chipsets that still have broken WEP encryption. All 11n implementations also support 802.11i/WPA2 with AES encryption. The transition to 11n will help eliminate the weaker, legacy security modes of 802.11a/b/g and focus on high security simplicity.

New deployment challenges. Like its soon-to-be-obsolete ancestor 802.11g, 11n provides for interoperation with legacy 11g and even (horrors!) the slower 802.11b nodes. While possible, such network miscegenation will result in severe performance penalties on 11n networks. This will further motivate the migration to 5 GHz, leaving the 2.4 GHz band to legacy 802.11 equipment.

And all that wireless speed? It takes a lot of wire to build a WLAN. The wire connecting those 11n access points will need to be upgraded as well. 100BaseT Ethernet is no longer enough. Gigabit Ethernet will be required to connect all those multi-radio 11n APs. The wired networks in large enterprises will have to be carefully architected to avoid bottlenecks.

Rapid consumer adoption. It is already happening, and will drive 11n integration into mobile clients. The leader in the consumer world, as in the original 11g Wi-Fi boom, has been Apple. Once again, it has gone “all in” with this new wireless technology. Apple’s laptops, their HDTV server and their APs are all 11n compatible – and not just compatible, but dual-band to get the highest performance. The majority of the other consumer-grade 11n routers out right now support only 2.4 GHz.

Inevitably in the enterprise. 11n has the potential to transform enterprise networks. It will take some time to roll out 11n infrastructure in the enterprise (though some, like Meru Networks, already have their plans in place). We need new network architectures and new planning and security tools in order to deploy 11n in a way that will deliver its full potential. It is not simply a matter of replacing your a/b/g access points with 11n access points.

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N is for Novarum. Stayed tuned for future installments in our wireless series as we examine the promise and pitfalls of 11n in more detail.



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