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802.11ac: Better Coverage, But Won't Hit Advertised Speeds
New submitter jcenters writes "Apple's new AirPort routers feature the new 802.11ac protocol, promising Wi-Fi speeds in excess of 1 Gbps, but Glenn Fleishman of TidBITS explains why we are unlikely to see such speeds any time soon. Quoting: 'When Apple says that its implementation of 802.11ac can achieve up to 1.3 Gbps — and other manufacturers with beefier radio systems already say up to 1.7 Gbps — the reality is that a lot of conditions have to be met to achieve that raw data rate. And, as you well know from decades of network-technology advertising, dear reader, a “raw” data rate (often incorrectly called “theoretical”) is the maximum number of bits that can pass over a network. That includes all the network overhead as well as actual data carried in packets and frames. The net throughput is often 30 to 60 percent lower.'"
Another issue is these routers are probably going to barf all over the spectrum, so as soon as you get a few of them operating in one area, performance will go to hell for everybody.
This has already happened on 2.4GHz in some areas, and is starting to happen on 5GHz too. Greater speeds require more spectrum.
"In theory, there is no difference between theory and practice. In practice, there is."
The term "theoretical" is not just standing in for "raw" data rate. In complex data communication, it also covers whether all frequency sub-bands, spacial directions, etc. are also available.
Use ethernet. Cables don't have these kinds of problems. I just wish somebody made lighter ethernet cables though, my iPhone cable backpack is killing me.
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I'm sorry, but since the advent of marketing (the new wheel, now travel up to 1000x faster than walking!) the speeds we actually get *very* rarely ever approach the advertised "up to" speeds. Even the summation says this: "And, as you well know from decades of network-technology advertising, dear reader, a “raw” data rate (often incorrectly called “theoretical”) is the maximum number of bits that can pass over a network. That includes all the network overhead as well as actual data carried in packets and frames. The net throughput is often 30 to 60 percent lower.'" So...... why bother mentioning it, let alone headlining it? Is it just to attract us grumpy old trolls? The advertised wireless network speeds are very much like gas mileage, wildly inaccurate in the real world.
The school curriculum should be amended so that every school child graduates school knowing that physcial layer rate > MAC layer throughput.
I should use this sig to advertise my book ISBN-13 : 978-1501515132.
The advertised speeds are used by normal people to estimate performance compared to other products. If this was the only product that advertised "raw" data then a distinction would be necessary. Using the same speed measurement conventions as the rest of the industry allows for an accurate performance comparison against other available hardware.
No one is going to exclude the new AirPort from their short list because it can't transmit 1 GB within a certain amount of time. The choice will be based on if it transmits the data faster than other routers.
I get over 1024Mbs on my AC setup....
More then likely, the WISP's will do what they have been doing, further increase there already illegal power output and blow consumer equipment out of the water.
Like in my area where we have 3 different WISP's in a giant pissing match making 2.4ghz almost useless for most peoples intended unlicensed usage.
Maybe 802.11ac is the kick the WISP's need to start making the investment and move to 802.11y and get off the 2.4ghz band.
for many devices, the ratings are best described as "we guarantee that this device will never perform any better than This, no matter what"
For example: for Cisco equipment, many admins mentally divide the advertised values by 10 to get some idea of what they are really likely to need, and if you have a really complex configuration, even that is grossly optomistic
Considering the vast majority of consumers use their routers for one thing: connecting multiple devices to their Internet service, upgrading in general is a waste of money unless you need better range because you have a large house. The 1 Gbps only does you good on communications between different devices on the local network, but most people don't use their network to talk to other PCs in the house, everything is talking to stuff outside the network where you're limited to the speed of you Internet service (so less than 20 mbps for most U.S. people).
I'm still plugging away on a WRT54G, and the only reason I'm considering upgrading is issues doing DLNA streaming from my PC in the bedroom to the blu-ray player in the living room because the blu-ray is getting too low a connection speed over wifi. This doesn't effect Netflix and other online services because of their lower (700-1500 kbps) stream requirements, but when things are having to get transcoded to MPEG2 on the PC sometimes bitrates can push past 20 mbps for the stream.
DECT 6.0 phones work on the 1900MHz band and more or less act like short-range cell phones with their protocols and compression. They work quite well, have decent penetration through walls, and are outside of the range used for computers.
I cannot fathom that any reader of /. would be unaware of theoretical vs real world performance, particularly in the networking space. This post is almost insulting.
So many injustices..so little time..
I have 802.11ac gear, and I'm getting about 8MB/sec whether on the 2.4GHz or 5GHz band. It's nothing anywhere near the pie-in-the-sky claims of 300mbps or 800mbps, but it is significantly faster than the 2.3MB/sec I was getting on 802.11g.
Wire based Ethernet is spec'd at MAC layer throughput. It is talking about the data rate of Ethernet frames, the 8b/10b encoding overhead is already accounted for and all that. So you discover that, particularly with Jumbo Frames, you get real near that speed in actual throughput.
Wireless Ethernet, not so much. You find that effective throughput, even under basically ideal conditions, are way less than the listed speed.
So it leads to confusion for people. Basically wireless is over advertising the speed.
if you can't offer us ftp or whatever transfer benchmarks about what the actual speed is, stfu because nobody cares and everyone has been using 100mbit cards that never ever push 100mbit/s for over a decade...
world was created 5 seconds before this post as it is.
stories without comments and comments getting lost on submission.
and this article is stupid. it doesn't offer real benches on .11ac. it's just stupid apple article trolling.
world was created 5 seconds before this post as it is.
We've already got an 802.11A standard, so how are they going to specify a router that uses all the standards? 802.11BAGNAC (ordered by speed)? 802.11AACBGN (alphabetical)? There were plenty of 1-character suffixes left, so why use a 2-character suffix that can be confused with an existing suffix?
Duh. Of course. So what. And when you bought that walkie-talkie that advertised 2-mile range did you expect to actually get that in the mountain valley, the city, the mall? Get a tad bit real.
Hello,
The problem with the current crop of 802.11ac adapters is that most of them have USB 2.0 interfaces (Edimax and Zyxel each offer a USB 3.0 adapter, and Asus has a PCIe card). With 480Mbit/s of bandwidth (and that's theoretical, since it does not include serialization, 8b/10b conversions, other overhead from peripheral bus communications, etc.) no one is is going to be getting anything near a Gbit/s of bandwidth over the bus even if they do have a strong signal. They may get better data rates due to technological improvements over previous generations of Wi-Fi (fatter channels, more MIMO streams, beamforming, etc.)
That will change as more adapters enter the market (probably in the form of MiniPCIe cards inside laptops), but consumers are not going to be much better off, bandwidth-wise, then going with 802.11n gear at home until the market for 802.11ac wireless adapters matures.
Regards,
Aryeh Goretsky
Dexter is a good dog.
they had a footnote next to the "up to 1.3 Gbps" claim, explaining that it's "Based on theoretical peak speeds. Actual speeds will be lower.". so, thanks for this enlightening article for us people who have no clue about technology whatsoever - and don't know how a footnote works or what the phrase "up to" means either.
So to clear up the confusion 802.11n rate specification should be "180mbps unless its higher, up to 300 or less".
I think you underestimate just how much I just dont care.
I'm not an Apple fanboi but do own a 2011 Macbook Air (2gb). The only real reason I still have a Desktop PC at home for web and video is because 802.11n cannot stream 1080p (at least not consistently in VLC over SMB). I do not want to buy an overpriced Apple Display for Gigabit Ethernet connectivity. So I'm stuck. I have an Ultrabook (docked to a 24" monitor) I'd like to solely use that's fast enough but it doesn't support the bandwidth I need.
Once the new Macbook Pro's are out I'll finally be able to upgrade to one of them and pair it with a new Airport Extreme (if 802.11ac can do 1080p in my apartment).
Sadly, I think at that point I will probably be masked as a fanboi even though I was really only looking for a powerful Ultrabook platform. None of which was previously possible unless I missed the marketing brochure from a boutique hardware provider (Sony) where they also started shipping 802.11ac.
Apple is once again lying to people??? You mean the iPad isn't really "magical"??? /mind blown
If i am reading things correctly in the IEEE draft (and i like to think i can read) 802.11ac offers absolutely NO increase in ACTUAL range compared to 802.11n.
You MAY get 1 or 2 feet (and thats about it) more range due to the additional mimo i/o's. But there really isn't any big leap here at all.
And what makes matters even worse the 5ghz band doesn't penetrate through walls very well at all.
Best to stay on 802.11n until draft 802.11r is fully ratified. Anything else is just a waste of money.
ps: The guy on lifehacker who wrote about 802.11ac had it wrong from the start!
The slashdot article is EXTREMELY misleading.
You WILL get better data rates at greater distances but the new draft will NOT give you better distance itself.
I am so sick of these misleading slashdot articles.
Must be a slow news day.
The 802.11 phy rates were always specified at a range of speeds to accommodate the varying wireless environment and varying capabilities of the AP and STA.
It is the amateur attempts to describes the 'speed' of the device in terms of the absolute maximum without explaining how the specification actually specifies things that is wrong and misleading.
I should use this sig to advertise my book ISBN-13 : 978-1501515132.