Good 802.11n info
Last Post: February 28, 2006:
This is an article that was written with information given by Atheros. Clearly that company supports the idea of 802.11n being backwards compatible with 802.11a/b/g. Remember that when reading the article. 802.11n is still a draft.
Regarding their push for backwards compatibility.....
I know I've only been in this business for 5 years, but why do we cling to the past so much? It is the very nature of technology to change and make yesterday's cutting edge today's butter knife.
You've got to live in the real world sometimes, my man. The reality is that overhauling a large scale network from top to bottom is impossible. It generally has to be done in bits and pieces. Having backwards compatible equipment accommodates that.
I think backwards compatibility is a must for real world implementations. In my environment I am rolling out 600 APs to 330 sites in the next 6 months. They are all 802.11b/g. The clients they talk to today are warehouse handhelds and forklifts which are all 802.11b. Had 802.11b and g not played nice with each other, I'd have been forced to use only an antiquated infrastructure because of client limitations. If 802.11n were a standard today, and I had the option of rolling it instead, I could only do it if it worked with 802.11b as well. It's just the facts of an enterprise. In my 24,000 user enterprise, laptop/pda office users only make up about 5% of my wireless, so I have to meet the lowest common denominator while also trying to stay ahead of the tech for the next wave of clients to hit the network.
Both valid points and reasons why G was accepted more than A. Although we must reach a point one day where we make something obsolete. Are we going to expect the standard after N to be backwards with B? I would hope that we as an industry would expect those still using B to get with the times.
I think many of us would like to "get with the times", but there are 2 obvious hurdles. The first, which is intensified's dilemma (and mine), is upgrading to the newer standard wouldn't just require replacing the wireless distribution infrastrucute, but also require ALL client devices to upgrade as well. I also have thousands of clients, and unless I want to use a pc card solution, (which I did to migrate from both FHSS and 802.11b), we are talking a huge expense, multiples of the expense incurred by upgrading the AP radios. Add to this the problem faced when many of your clients don't actually work directly for your organization, in my case doctors and specialists, whose hardware I can not dictate. I also am forced to cater to the lowest common denominator. The second dilemma would be the manufacturing industry at large. There was quite a wait for 802.11g solutions to be available in handheld devices, and I'm not sure how many, if any 802.11a solutions are out there now, (and I'm talking built-in, not large external modules like yellowjacket). What kind of power drain is MIMO going to incur on a portable device? I would guess significant. Until the manufacturing industry is prepared to do huge rollouts of client solutions that cover the spectrum of device types used, I would have to lean towards backwards compatibility as well.
You sound like a typical networking guy gone astray. Remember the job of a network professional is to *support* the end users. The applications they run bring in the money that makes the company go.
If an end-user runs an 802.11b application that works just fine and requires no upgrade, what's the best path to supporting them? Installing a whole separate infrastructure that might interfere with their old 802.11b system of integrating them in to a system that is backwards compatible?
I'm not fighting either way, nor have I gone astray. I see both sides of the coin and thats what I'm trying to get others to do. Personal stabs should not be necessary Ben. Should you feel the need, they can be directed to me through my MSNM or the forum PMs.
I'm not saying N shouldn't be backwards compatible. What I am saying is that we can't expect every new standard that comes out from here to eternity to be backwards with standards that came out in the 90s. You reach a point in any product's lifecycle where you are forced to upgrade. I'm willing to bet that when N's successor comes about, there's gonna be this same issue and everyone's gonna wanna keep backwards compatibility with B. I'm proposing the idea of a cut off. New standards should be backwards with the two previous revisions but no more.
Just to throw more in the pot, if we go 2 revisions back, that would make "n" compatible with "b" and "g", but would leave "a" out in the cold, although because of strange circumstances "a" became more widely accepted/distributed post "b" and "g". Maybe what we're looking for is more modulation techniques, i.e., "n" should be compatible with OFDM and DSSS, but not FHSS? Then this throws in allowable spectrums, does it need to be 2.4G and 5G compliant/capable?
I didn't mean it as a shot at you, man. I was just pointing out that you always have to think support first in the networking world.
I am sympathetic to what you are saying about cutting off legacy standards at some point, but I just disagree. Remember, you can always just configure the network to not support legacy terminals. I mean, that's why these engineers get paid -- to figure out how to support legacy technologies and high speeds in the same product.