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dbeberman 12/5/2012 | 12:17:48 AM
re: Extreme Hatches Switch Surprise WLAN Switches, Aruba, Vivato, how much bandwidth are they really getting?

I’ve read articles on Unstrung about WLAN switch boxes (or shared media hubs), and beamsteering antennas. Vivato claims 33 Mbps. over 100x100 meter office area with 802.11b. Aruba claims 2 Gbps. Capacity with 802.11b.

Here’s the thing, 802.11, without counting any interference from overlapped access points, or hidden nodes, or reduced data rate because of blocked signals, will suffer from increasing numbers of collisions-and-retries as the number of users increases. These collisions cost the network real data throughput, and the congested network phenomenon results.

Vivato claims they can support 150 users in a 100x100 meter office space. That’s about 105,000 square feet. This means that each user occupies about 700 square feet of office space. This means 150 devices congesting the wireles LAN. This means that whenever there isn’t sufficient signal strength between a mobile device and the Vivato antenna, the data rates train in steps from 11 Mbps. down towards 1 Mbps.
Any time a mobile device trains down the data rate, it means that packets take longer to transmit on the network. This means there is less network available for other devices. Which in turn means more collisions and more congestion.

Can an 802.11b network deliver more than 2 Mbps. actual data throughput reliably with more than a handful of users? Where does that leave the Vivato system, perhaps 6 Mbps. (upto 3 simultaneous beams claimed), total throughput for 150 users?

Aruba Networks claims 2 Gpbs. capacity using 802.11b. That translates to just over 180 Access Points.
The question is, can you really use the claimed 2 Gbps.? If an Access Point has a coverage radius of 250 feet for 802.11b operation, then 180 AP’s will cover about 35 million square feet. (PI*R*R) * 180.
Since I don’t think that’s what Aruba Networks had in mind, lets try putting the Access Points close together. If you don’t reduce the power, the AP’s will all interfere with each other, let alone all the devices interfering with each other. If you do reduce the power, then the distance that your mobile device can be from the AP and experience the full 11 Mbps. data rate is severly reduced. Even with reduced power, the nearby mobile devices will act as hidden nodes causing interference, while the co-channel interference from the neighboring AP’s will further reduce the actual data throughput of the wireless LAN.

Lets say you use 180 AP’s in the same 100x100 meter space that the Vivato antenna covers. Essentially every AP can hear every other AP. 802.11b has 3 channels. So lets assume that 60 AP’s interfere with each other on each channel. Lets further assume that mobile devices must roam between these AP’s as they move within this office space, causing hidden node problems, and perhaps some unintentional oscillating between AP’s as the mobile devices try to pick the best AP to associate with. Again, how much actual data throughput does the wireless LAN support? Somewhere between 2 – 6 Mbps.?
Maybe it’s a little better than a Vivato antenna, maybe a little worse. Is either one really much better than a dialup modem in the office environment?

Whats really needed is a wireless LAN technology that can scale to real data throughput of 100’s of Mbps., reaching the equivalent of a Gigabit per second wired network, in a 100x100 meter office space.
A technology that is immune to congestion problems, co-channel interference problems, hidden node problems.
A technology that is resistant to temporary moving obstacles, (such as co-workers), between the mobile device and the Access Point.
A technology that can deliver a sustained network efficiency of better than 85% of the actual maximum wireless LAN maximum data rate.
A technology that can deliver better than 45 Mbps. of real data throughput on a 54 Mbps. WLAN network. A technology that is easy to deploy and doesn’t require extensive site surveys to carefully place Access Points, since neither the number of Access Points nor the number of mobile devices has any effect on the performance and throughput of the network.

What do you call such a technology? Where do you find such a technology?

Corporate WaveNet, Inc.’s TRUEratetm at www.corporatewavenet.com.
deepciscothroat 12/5/2012 | 12:17:46 AM
re: Extreme Hatches Switch Surprise Vaporware
Who really cares
Tie 3 APs together
And Vivato's a not starter
Where's the meat
Where do they eat
Who's using it
Skip this vaporware shit
dbeberman 12/5/2012 | 12:17:41 AM
re: Extreme Hatches Switch Surprise >>Vaporware, Who really cares, Tie 3 APs together
>>And Vivato's a not starter, Where's the meat
>>Where do they eat, Who's using it
>>Skip this vaporware shit

A response:


2 Years of R&D effort.
Reviewed by university academics and industry technologists.
Algorithms implemented and demonstrable, working on open source simulation platform, Network Simulator.
If that's vaporware, then I'm proud to call it vaporware.

Try tieing 3 AP's together to cover an office of 100 users. I don't know of too many MIS departments that are going to buy into a new technology that might deliver only 6 Mbps. Especially when the bandwidth drops just when everyone needs it most, because of congestion. (That’s what you might get with the current technology).

If all the AP's are on the same channel in a 100x100 meter space, then this is really only 1 channel, since the AP's all "hear" each other.
Assuming that the AP's are perfectly positioned so that every device is able to communicate at
peak raw data rates, the collision overhead alone may eat up almost 70% of the bandwidth, with heavy
traffic loads.

If the AP's are on different channels, and all the users are distributed exactly such that each AP only has 1/3 the users, and all the users are within range such that they enjoy maximum data rates, then perhaps the users can get enough reliable data throughput.

What happens if too many users are within range of only one of the AP's?

What happens if some users need to be down the hallway a bit and connect at a much lower data rate slowing your wireless LAN to a crawl?

What happens when other wireless LANs are installed around yours, and the unexpected
co-channel interference and resulting hidden nodes corrupt your network?

What happens when you run out of channels to switch to?

Maybe these things won't happen on your network, but wouldn't it be nice if you didn't have to worry about it?

More importantly take every single RF data communications technology that you have
ever heard of and analyze the real throughput possible with the number of users in a normal
corporate office space, and see if it can come close to offering the level of sustained efficiency this technology offers.

TRUErate technology delivers efficient, deterministic, congestion free, data throughput. It does it using an entirely new approach to solving the multiple access problem. It increases
data throughput, not through better antennas, or more power, but through greater network efficiency.

TRUErate is a new technology. You won’t find it in any of the products on the market today. When the next generation of wireless LAN chips have TRUErate inside them, your old WLAN NIC cards will still work so that you won’t lose your initial investment.

But just like black&white TV gaveway to Color TV, when you want your network to have all of the benefits of TRUErate, you will be able to incrementally replace your NIC cards with TRUErate enabled NIC cards.

[email protected]

wifi_radio 12/5/2012 | 12:17:41 AM
re: Extreme Hatches Switch Surprise To ciscowireless,

bla bla bla bla bla bla .... wow, i'm bored now. Gotta go to sleep. Seriously, cisco is just playing as a big a** bad company ... trying to create a confusion on the market and slow it down. The same trick like what Microsoft is doing basically. The big evil company is afraid that someone out of nowhere is trying to grab its lunchbox money, so one way of doing it is basically to scare the potential new customers to deliver all talks about vaporware sh**.

Nuff said. The market will decide whether it's buying from Cisco, Vivato, Aruba, and others. The more selection of products available on the market, the better it is to get a good deal. Remember to start negotiating from the car' invoice price (by getting the info from the Internet such as kbb, edmunds, etc) instead of from the car' sticker price on the lot.
airbb 12/5/2012 | 12:17:39 AM
re: Extreme Hatches Switch Surprise "But the trend Extreme is joining is bad news for smaller 802.11 outfits. Incumbent players entering the market have two significant advantages over startups. First, on the business side, they can sell through existing channels and to an installed customer base. Second, on the technology side, they have spent years developing management capabilities. Startups are working from scratch in both regards."

Obviously, the author never worked in one of these companies.

- How did Extreme come to existance?
- Why didn't Cisco prevent all other successful startups?
- Why does Cisco keep buying other startups for the technologies?

Incumbent players entering this market have five significant disadvantages over startups.

1. Company lost touch with the market change
2. Managements are not taking risks
3. Engineers not motivated to be creative
4. Product development cycle is unreal
5. Product and R&D costs are too high

Virtually, every successful technologies that we enjoy today are started by startups, i.e. PC, Internet(or was it Al Gore?), IP, ATM, DSL, TiVo and WLAN AP.

More realistic statement maybe "Incumbent players will buy the successful startups and sell it to the massive markets.

If you don't believe me, just ask ciscowireless.


deepciscothroat 12/5/2012 | 12:17:32 AM
re: Extreme Hatches Switch Surprise Hey Airbb
who's buying your products baby?

deepciscothroat 12/5/2012 | 12:17:32 AM
re: Extreme Hatches Switch Surprise So CEO of some weird company is selling his products on the message boards. How creative. Like that GO experiment with Jerry Kaplan

- $75M down the drain and all we got was a stupid book that blamed the GO fiasco on everyone else.

Corporatewavenet (great name?) is toast
Illongot 12/5/2012 | 12:17:02 AM
re: Extreme Hatches Switch Surprise Perhaps y'all missed the point of the article...Xtream going into the WiFi market simply gives them a strategic way to "cross the chasm" and gain a foot hold in the consumer market where UBW has its ultimate potential.

Go ahead and put your head in the sand and think that this is all about the 802.11 market and ignore/dismiss the competition.

IF/WHEN the FCC breaks down and goes against the all powerful Wireless Operators wishes and lifts the restrictions on the power cap on UWB...Cisco will have to pay a hefty sum for Xtream's or Time Domains' IP.

PS. Note that the FCC has already opened more 'free spectrum' for the 802.11g / 5.8Ghz market much to the chagrin of those that paid billions for spectrum rights and invested heavily in 3G, and there is no reason to think that they will not do the same in UWB
see: http://www.wirelessweek.com/in...
Illongot 12/5/2012 | 12:17:00 AM
re: Extreme Hatches Switch Surprise My mistake...had a collegue point out that I was thinking of Xtream not Extream...sorry cisco etal.

jacksullivan66 12/5/2012 | 12:15:14 AM
re: Extreme Hatches Switch Surprise Even though you got the company wrong both times, Illongot (it's Xtreme Spectrum, not Extreme Networks, or Xstream?), at least you were hinting at the right subject...

Who out there doesn't think Bluetooth is complete toast (not that it wasn't heading that way already). Let's see:
Bluetooth = low power, small form factor, low cost, 10M range, and roughly 1Mb/s throughput.
UWB = lower power, smaller form factor, low cost, 10M range, and roughly 100Mb/s throughput.

And that's only in first generation silicon!

Several PHY manufs will likely announce by the beginning of next year 2nd Gen silicon at roughly 480Mb/s, and the IEEE 802.15.3a standard (on track for a final draft status by Nov of this year) has a silicon roadmap that includes throughput to 1Gb/s.

The question is, why are people only talking about UWB as a consumer device / home networking play? Are you kidding me? UWB at 480Mb/s replaces not just USB1.1, but USB2.0 (which is just coming out)! As a matter of fact, there isn't a cable on most users desktops that will achieve that rate of throughput, even with the cost and hastle of a physical wire.

If Intel has their way, expect an all CMOS UWB radio on the corner of every pentium die they produce by the end of the decade. In that world, all in-building short and intermediate range communication will occur over UWB...

802.11? Relegated to 2nd class status because it just can't stack up to UWB in short and intermediate ranges...
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