Networking

802.11n equipment is morphing to meet new demands

Others have presented the idea that equipment based solely on 802.11n will not adequately support emerging applications. If the technology displayed at this year's CES is any indication, Wi-Fi chip and equipment developers are beginning to agree with this assessment.

New applications mean new requirements

From early on Wi-Fi has been focused exclusively on data traffic pertaining to home and business applications. Now, Wi-Fi is seen as a viable network transmission medium for a variety of non-PC devices and their associated applications. HDTV equipment, gaming consoles, smart phones, and alternative audio/video streaming devices are some that come to mind. Adding these alternative devices to a typical 802.11a/g network can and usually does create frustrating throughput and Quality of Service (QoS) issues.

So, it is not sufficient to just have a bullet-proof Wi-Fi network that is reliable, high bandwidth, affording great coverage, and uninterruptible RF propagation as envisioned by 802.11n. The Wi-Fi networks of today need to have cutting edge QoS enhancements as envisioned by 802.11e. These enhancements allow the network management system to be intelligent enough to determine the type and priority of all of the traffic—VoIP for example—passing through the network.

By understanding this, 802.11n chip and equipment manufacturers instead of just meeting the criteria laid out by 802.11n, are adding enhancements that meet or exceed perceived requirements being presented by new home, SOHO, and enterprise customers applications.

Improved silicon

Broadcom and Atheros, two major developers of chipsets for Wi-Fi devices have displayed some new and very innovative chipset features at CES this year. Interestingly enough, these features directly correspond to the QoS and bandwidth requirements of the emerging applications. It is also apparent that both chip makers now understand that Wi-Fi will be the network of choice for streaming traffic especially video. There is even a new term: "visual networking" as coined by Cisco CEO John Chambers.

At CES, Broadcom presented a new 802.11n chipset that uses 65 nanometer technologies. Broadcom is also definitely paying attention to "visual networking" requirements by developing a dynamic power control component. This feature provides a sensory intelligence that controls RF power levels depending on the physical distance between the access point and clients. This allows more RF output to be focused on the clients that are further away. To complement the power control feature, Broadcom also has improved bandwidth management capabilities of the chip to handle the new and more demanding applications that are sensitive to bandwidth fluctuations. Additionally the new chip has a smaller footprint than previous chips, which leads to more efficient power consumption. Finally and what is even more amazing to me is this chip's ability to simultaneously transmit on both the 2.4GHz and 5 GHz bands.

Atheros also displayed some amazing new technology at CES, with a great deal of thought toward the new emerging applications. Atheros has made both hardware and firmware improvements so the chip will be more sensitive to QoS priorities of the network traffic, especially traffic inbound from the WAN connection. Even more interesting is the work being done by Atheros on a bandwidth allocation algorithm. The algorithm has the ability to sense multiple incoming data streams, prioritize the data streams according to QoS markers found in individual packets and apply the appropriate bandwidth to each data stream. Creating an algorithm with this ability is not a trivial task and in my opinion pretty darn cool.

Hardware also gets a makeover

Equipment developers as a whole are no longer as focused on any single Wi-Fi device, but are beginning to realize the need to consider an entire Wi-Fi network as a symbiotic system requiring a central intelligence. With that in mind, equipment developers are hard at work making sure their devices will make use of the newly developed intelligence built into the 802.11n chips. Developers are also peering into their crystal balls trying to determine what 802.11n will eventually look like, since it appears that ratification of 802.11n will not take place until mid-2009.

Putting that nebulous challenge aside for a moment, developers also have other real-world demands to deal with: emerging applications and technology, working in hybrid networks with legacy 802.11 equipment, improved performance in an ever-more crowded RF environment, and trying to convince the public that now is the right time to buy 802.11n equipment. Definitely enough to think about.

One area that will become extremely important to equipment developers is the use of "metamaterial" antennas. This technology has the potential to revolutionize microwave RF propagation. Antennas using "metamaterial" technology can bend RF waves more than antennas using present day technology, which results in smaller antenna systems. Being smaller in size allows the use of more antennas in a smaller space, creating conditions for improved RF reception and transmission. Antennas using "metamaterial" technology also have the capacity to transmit on either the 2.4GHz or 5GHz bands, they can be set to cover selected horizontal sector coordinates, and through coordination from the chipset determine and use the optimal RF characteristics for a specific remote client.

2008's main controversy

The big debate of 2008 will be whether to start using 802.11n equipment even though the amendment is not ratified. There are numerous well-written articles making points for either side. Two of the better articles are written by Joanie Wexler, and published by Network World. Part one emphasizes the opinion of Chris Kozup a Cisco senior manager. One comment of his that I find extremely fortuitous is his perception of the relationship between IEEE specifications and Wi-Fi certification:

"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."

Part two presents an opinion by Joanne Lenno from Nortel's WLAN marketing group. Lenno is a proponent of the "wait and see" attitude and makes several good points about why this maybe the best approach:

"There are infrastructure concerns. If the throughput benefits of 802.11n are to be realized, the WLAN architecture must be able to support higher traffic volumes. Edge switching capacity and switching power also need to withstand increasing requirements. Without GigE, APs generating around 100Mbps will be artificially constrained. And, today's 802.3af PoE can't supply enough juice for maximum data rates with MIMO. The better fit will be with the coming 802.3at [IEEE PoE Plus standard]."
Final thoughts

My personal take is that 802.11n should be considered for each specific situation and not make all encompassing generalized decisions. I have setup several point to point links recently using 802.11 equipment. During initial testing, I determined that the point to point links would not be possible if I had to use legacy 802.11 equipment. After further testing, I found that 802.11n equipment did not have the same throughput and RF environmental issues, allowing the successful setup of the point to point links. Sure the equipment is Draft 2 and maybe out of spec within a year, but the existing equipment filled a very valuable need that was not financially or technologically feasible any other way.

I also am very excited about the technology behind "metamaterial" antennas systems and hopefully you are as well. I plan to cover that cutting edge subject in my next post.

About Michael Kassner

Information is my field...Writing is my passion...Coupling the two is my mission.

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