802.11n - The official delivery of pipe dreams

The IEEE's 802.11n standard is supposed to bring high speed wireless to the masses.
It's been in draft longer than most can remember, and from the schedule it appears that it won't be out of draft release and make it to a final specification until Dec 2009. This is from a working party that was setup in January 2004!

Sure there was a rival groups in the early days, but as of July 2005 these rivals (TGn Sync, WWiSE, and MITMOT) all agreed to merge their proposals into the TGn draft.

Last month we saw Draft 4 of the specification approved, and there is already talk of a Draft 5... how many before we get something into our hands?

Sure, there is a bunch of 'Draft 2.0' 802.11n devices on the market. It's risky business deploying one now. Why?

• Being at 'draft' status each manufacturer has a different interpretation of the standard. This can mean that different manufacturers equipment is unlikely to work well (if at all), in addition different releases from the same manufacturer has no guarantee of interoperbility
• There is no guarantee that these devices (wireless cards, embedded chips and Access Points) will be upgradeable to the final specification.
• Not all the details of the specification have been sorted out (thus the draft). You're likely to run into some 'interesting' issues.

Even before the release, 802.11n will be a failure. Harsh words yes... but let me explain.

Many believe it will be the silver bullet for networking, with the promise of delivering 600Mbps. Many read that as 'data throughput' - that's not the case, it's raw bit-rate.

How many people to you currently speak to that use an 802.11g network whinge that they aren't seeing 54Mbps transfers?

Expect anywhere between 30-70Mbps in real world data-transfer rates.

Many have moved their cordless phones from the overburdened 2.4Ghz spectrum up to the 5Ghz area. (Just look at any new cordless phone -- most are shipping in this space). 802.11n will operate in both the the crowded 2.4Ghz space and the 5Ghz range.

Expect to see the same issues we saw when 2.4Ghz wireless networks first came out with a range of devices interfering with the 802.11n network. (on either 2.4Ghz or 5Ghz).

MIMO (multiple input, multiple output) does help somewhat, in extending the quality, range and provides multiple streams.

The draft allows for up to 4 antennas on either end, but you'll be lucky to see one of these. Expect dual antennas to be the norm.

In addition, high-throughput will require high performing CPUs (particularly if you have encryption enabled -- which should be unless you want to be wifi-jacked). Home wireless network routers are notorious for having underpowered CPUs... whilst they will get a little jump in grunt, expect them to falter if attempting several large data transfers at the same time.

It appears 802.11n routers will be a mine-field for some time for consumers, there are loads of options and those cheaper ones are likely to miss the bells and whistles... watch out for the cheapies that can't do both bands. Many are working solely in the 2.4Ghz range. Most of those on the market presently are only Draft-2.0 models, so they are quite a fair way from the 'final spec' (We know of 5 drafts at least prior to the final spec).

Ars Technica has a great review on current 802.11n routers. What they have to say doesn't suprise me. These are speeds all running in 802.11n mode and show the average of UDP/TCP throughput results at multiple locations:

Device	2 feet	25 feet	35 feet
Apple AirPort Extreme @ 2.4Ghz	22.75Mbps	25.15Mbps	17.80Mpbs
Apple AirPort Extreme @ 5.0Ghz	44.30Mbps	34.20Mbps	12.65Mpbs
Netgear RANGEMAX Next Wireless Router	28.48Mbps	24.83Mbps	5.39Mpbs
D-Link XtremeN Wireless N Gigabit Router	56.10Mbps	17.42Mbps	FAIL!
Linksys Wireless-N Gigabit Router with Storage Link	44.37Mbps	20.10Mbps	10.70Mbps

For those Aussies wonder what the feet is in metres (well it was a US review).
1 metre ~= 3.28 feet. On the flip side, 1 foot ~= 30.48cms

So these results were measured at: 60.96cms, 7.62 metres, and 10.67 metres. Nothing out of the ordinary and actually relatively close for at least the first two. If you were < 1 metre away, just plug in an Ethernet cable!

One thing 802.11n will deliver is supposedly better range. so those struggling with dropouts on a 802.11g network may like the upgrade... though it will come at a cost. Don't expect the devices to come cheap. A 'decent' 802.11n device currently costs upwards of $200USD.... plus adding in all the cards you'll need, you could be up for some serious dollars.
From all reports if you want the range and speed - get the 5.0Ghz models.. though if it doesn't support 2.4Ghz you won't have backwards compatibility with 802.11g devices.

You will also notice most currently advertise 270Mbps or 110Mbps..... it's no where near real-world results. I would love to see one of these manufacturers demonstrate their delivery of these speeds, to date -- we haven't seen anything near them. Advertising raw bit speed is also misleading and these makers know it... they are aware when people look at speeds they normally are looking at 'real world' speed performances. I expect more outrageous claims to be made and the infamous 600Mbps will soon start to be sprouted. Realistically on a '600Mbps device' -- don't expect anything beyond 80Mbps. See that Ethernet cable isn't looking that old at all.

Me, I'll stick with 802.11g for the time being.. . I only use it currently to get to the Wii and the MythTV box. Occassionally I might use it for our laptops or visitors (if I can't be bothered running an Ethernet cable from the switch).

I'm laying Gigabit Ethernet on Cat6 throughout my new house (48 ports baby! ), and expect that all bar the Wii will be on that.

For streaming High Definition Video, don't expect your sparkling new 802.11n device to handle it, or if it does, don't expect multiple streams.

For a specification that been in the thinking tank now for 4 years, the current speeds are pretty disappointing.