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It's an interesting predicament in the enterprise. Thanks for the whitepaper and the insight. It offers another perspective on things. We spoke of this briefly last night over the CWNA or Bust CC.

Wilddev (Chris),

Thanks for confirming the protection mechanism on 802.11g. I "thought" it was correct, but appreciate another listening ear. (you can't have too many wifi techies on a single blog, can you??)

I think you will love the Netgear router and since it is dd-wrt, it really does not matter "who" makes the firmware. Also, I saw the Gigabyte link. Just a sidenote, the Intel 5300 client card was the bomb! I say "was", due to the fact that I know I saw (per www.wi-fi.org) that it was certified with 3 spatial streams for 5 GHz in 802.11n. I don't know of another client card that is certified by wi-fi.org with three streams. But, the web site has been recently revised to certify the 5300 card as only 2 spatial streams (this is the std card we use in all our Lenovos in house). It is a good card and very easy to very configure with Intel ProSet client software (much better than any Micro$soft product and almost as good as Odyssey Client). My bottom line is that I am still looking for a 3 spatial stream client card AND AP. So far, I know of none. Marvel has a 3 spatial stream AP, but I am not sure if it is just their chipset or if they actually make the AP to go with it. If 3 steams are realized, you can approach 450 MBps. (Yes, I have a need for speed--for testing purposes,of course...)

JCB,

If you flash the Netgear (or any router that is dd-wrt compatible) with this dd-wrt flash, you can use the http GUI to program in scripts as well as access it directly throught the command line interface (CLI) via DOS prompt. I usually use the http interface, then write any needed scripts and copy/paste them in the command line box and hit save. There is just so much you can do with dd-wrt and although you would not want it for enterprise work (although, I do have our church WLAN - 4 APs- all flashed dd-wrt and data roaming works very well) it is great for testing and learning about wifi theory. Here is a wifi of the main support pages--just a lot you can do with this AP flash (which is Linux based): http://www.dd-wrt.com/wiki/index.php/Main_Page

OK at the expese of looking stupid,or for clarity as far as I know 3x3 is three transmit and three recieve OK I think we can all agree on that.

The question then it "This actaully has no relationship to spatial stream" in that you could have two or three spatial streams in a 3x3 access point?

OK I pray thats not as stupid a question as it appears.

Some very big knowledge gaps!!!!!!!!!!!!!!

Here is a three spatial stream ap

http://www.marvell.com/platforms/dual_band.html

Some vendors are using the 3X3:2 type nomenclature to denote TransmitXReceive:Spatial Streams. Not all 3X3 are 3X3:3... buyer beware!

Keith

Thanks Keith. Good to know.

Thanks for the info Glenn.

I was unaware that Cisco and/or the WFA changed the WFA listing that showed 3x3 to show 2x2 for the Intel 5300. I checked, and you are correct. Although, from the dates on the website, it looks like they were [b]never[/b] 3x3. It makes me wonder if some kind of shenanigans are going on.

The WFA site shows three 5300 Wi-Fi cards. [u]All with the same Product name[/u] "Intel WiFi Link 5300" [u]and all with the same model/SKU#[/u] "5300AGN/533AN_MMWG". All of these were certified on different dates, have different certification numbers, and most obviously, different capabilities. Two have WMM-PS, and one does not. 802.11i security coverage differs too. All are 2x2 and certified as 802.11n [i]Draft 2.0[/i], and were certified from mid to late 2008. The last certified, seems to be the least advanced.

There is no 3x3 5300 in the WFA database.

I think the best thing to assume is that [i]you may get anyone of the three in a product[/i]. Hopefully all three versions are flash upgradeable, but I don't have anything to substantiate that. The Intel site seems to have two driver versions available for download, but not much detail is readily available.

The Intel site shows the "Ultimate N WiFi 5300" as being a 3x3, but I don't see any claim that they are WFA certified. They do claim support for Cisco CCX v4.

I think this is just another indication that some manufacturers change the hardware, and don't change the model numbers. I've had several clients bitten by this practice. It can make buying used equipment risky.

I have some other interesting observations I'll post later under a different heading.

What I think it does mean, is that Intel has a non-WFA certifed 3x3 version, that is compatible with "some" AP's.

Its interesting that 3x3 does not always mean 3 spatial streams as what I undestand from a very simplistic point is this.

3x3 = 3 radios each with a transmitter and receiver if it was 2x3 that would be 3 radios two with transmitters and all three with recivers.

Now the spatial stream is from the Tx side so a 3x3 SHOULD have 3 spatial streams. How can a 3x3 NOT have 3 spatial streams, are they just lying and using marketing speak

Intel definitely uses marketing speak at times......

For now, let me say that the Intel 5300 pictures definitely show 3 U.FL Antenna connectors on the cards, so a 3x or a x3 probably belongs in the description somewhere.

If you link to the Intel site from the WFA site, using the Link on the left of particular product declaration, you will almost always end up at the [u]same[/u] Intel search page.

Originally, the various manufacturers links took you to a unique product page that further described the specific product (on the mfg's site) that you were interested in. Over the last couple years, several manufacturers have stopped doing this.

I once asked the WFA about this practice and was told it was up to the manufacturer, not them. In some cases this may be due to simplification, but obviously it also makes it easier to obfuscate things.

I have no problem with devices having the same product number, but I would like to see a version or revision number attached.

Wlanman09,

Yes, I think WFA changed their 3X3 -- or-- they removed the 5300 Ultimate. Notice on the Intel site they list their 5300 as "5300 Ultimate", but the term "Ultimate" is not on the WFA site. But, I did see it--it was there.. WFA does not denote the model and type of the card (I wish they did) I am also confused by the numerous listings/certification dates for the several 5300 cards noted. Your comment on WFAs response that it is up to the mfg is also interesting. I always thought wi-fi.org did their own testing, certification, etc. Maybe not...??

Also, I am not an 802.11n guru by any means. So, I need help. I have a GREAT AirMagnets (now owned by Fluke) 802.11n chart on my wall at work. A terrific reference tool. It might still be avaliable, not sure. Spatial streams have the nomenclature of "M x N:S", indicating the number of transmit (M) antennas, number of receive (N) and number of spatial streams (S); So, a 3x3:3 indicates 3 transmit, 3 receive (antennas) and 3 spatial streams. (I wished 802.11n writers had used Tx/Rx for transmit/receive as is common in the RF/amateur radio world...). As for U.Fl. connectors--3 would be needed for three Tx/Rx antennas (see, there's the ham radio in me coming out...). But even our lower end Intel 4965AG_MM1 cards MIMO cards have 3 U.Fl connectors--two for Tx and one for Rx (so marked on the card), . So, be sure to consult mfg documentation to verify all antennas and spatial stream capbilites.. Lastly, having 3 spatial streams does not guarantee max throughput. STBC and transmit beamforming are other optional 802.11n features that help with signal reliability and concentrating signal energy in direction of receiver. OK, one more lastly-lastly. The new CWNA book has a great chapter on 802.11n technology. That chapter used to be in the CWNP white paper section, but not sure if it was removed when the book was released, but definately a great tool for 802.11n technology.