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802.11ac: Better Coverage, But Won't Hit Advertised Speeds 107

Posted by Soulskill
from the are-you-implying-marketers-would-lie-to-us?!? dept.
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.'"
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802.11ac: Better Coverage, But Won't Hit Advertised Speeds

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  • by ZorinLynx (31751) on Friday June 14, 2013 @03:53PM (#44010541) Homepage

    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.

    • by phizi0n (1237812) on Friday June 14, 2013 @04:04PM (#44010657)

      5GHz doesn't penetrate well so you won't get much interference from neighbors except maybe in very small apartments, the real problem is other devices within your home that use 5GHz such as cordless phones.

      • Re: (Score:3, Insightful)

        by h4rr4r (612664)

        1. That is the best thing about moving to 5Ghz
        2. Throw those things out, while you are at it get rid of the fax machine. Cordless phones have all the disadvantages of cell phone and landlines together for maximum failure.

        • by SJHillman (1966756) on Friday June 14, 2013 @04:13PM (#44010751)

          My apartment is in a cellular dead spot. My landline only has two ports... one in the kitchen and one in the master bedroom. It would really suck if I couldn't use the phone in the living, garage, basement or office without having a long-ass cord getting tangled on everything. So maybe cordless phones do have a purpose after all.

          • by h4rr4r (612664)

            What you really need is a cell phone booster.

            You can thank me later.

            • Re: (Score:3, Informative)

              by exodus2 (88214)

              I got a notice today from Sprint that they are canceling my Air rave which gives me an indoor cell tower

          • by MightyYar (622222) on Friday June 14, 2013 @04:42PM (#44011019)

            And "landline" (or internet) phones are still waaaaay cheaper than cellular. Free, even.

            • by antdude (79039)

              And faster and more reliable for emergencies like 911.

            • by Molochi (555357)

              I can do a basic mobile phone service for about $30 per month. That includes any US long distance calls.

              I have a phone on the wall that can dial 911 for free.

              I prefer my lowfi Android Cricket connection. $65 per month that gives me unlimited US calls, text, sms, and specifically allows tethering(wifi or usb). It has a data transfer limit of only 1GB per month, but after that they don't charge you they just throttle your bandwidth to ~128kbps. I can usualy still find an open wifi AP for my laptop , but it's

              • by evilviper (135110)

                I prefer my lowfi Android Cricket connection. $65 per month that gives me unlimited US calls, text, sms, and specifically allows tethering(wifi or usb). It has a data transfer limit of only 1GB per month

                Sounds like you're getting ripped off. I'm paying $40/mo with Boost Mobile (Sprint) and have similarly unlimited service, nation-wide coverage without roaming, and data was only just recently capped at 3.5GB/mo before throttling.

                It's true they don't explicitly allow tethering, but it's a simple matter to in

                • by Molochi (555357)

                  Yeah I guess Cricket isn't the deal it once was. You say Boost doesn't explicitly allow tethering, do you know if they have anything about it in TOS?

                  FWIW Cricket was "allowing" (they weren't actively blocking) tethering and didn't have a data cap in place, on a $40 plan, back when I put this phone on their network. But they've moved to actively looking for and blocking use of tether apps, (charging 5bucks to use them) and only allowing that "feature" on their 60 dollar smartphone plan. If I could do without

              • by MightyYar (622222)

                Yes, I have cell phone service, too. It's $30/month for 100 minutes and 5GB of high speed on T-Mobile. I usually use about $10-15 more at $0.10/minute, for a total cost of around $45/month. But that's my toy tax. My home phone is an OBI that hooks to Google Voice and makes and receives free calls. I pay CallCentric $1.50/month for 911. So even if you stretch the OBI price over a single year, I'm only paying $6/month. This time next year it will be $3.50/month. The economics are similar for the other "pay on

                • by Molochi (555357)

                  I like that OBi.

                  And you can use something like GrooVe IP on an unactivated smartphones over WIFI.

            • by evilviper (135110)

              And "landline" (or internet) phones are still waaaaay cheaper than cellular. Free, even.

              You can find nearly free cell phones if you want... But almost nobody wants them... Just like land-line phones.

              And land-line phone service is no longer cheaper than cellular in the US, perhaps with the exception of folks on the fringe coverage areas. In fact it can be considerably cheaper, starting at about $7/mo if you don't make many calls, and topping out at about $30/mo for an unlimited voice plan on any of severa

              • by MightyYar (622222)

                You can buy a Obi or Magic Jack or whatever and pay nothing at all after the initial purchase price. I'm unaware of anything like that in the cell phone world.

                If you don't use your phone, then yeah you can go cheap, but $7/mo is still more than you will spend on a VOIP phone if you don't use it (in fact that will get you 500 minutes at a place like CallCentric).

                • by evilviper (135110)

                  but $7/mo is still more than you will spend on a VOIP phone if you don't use it

                  Is internet service free, now?

                  • by MightyYar (622222)

                    I didn't feel that I needed to say that, it is so blatantly obvious. These numbers all only work if you are already paying for internet.

                    • by Molochi (555357)

                      I agree with this. I wasn't really aware of OBi like products or thinking about VOIP apps because I personally make make most of my phone calls between locations.

                      For the ultimate savings you might have to combine Mobile and VOIP ...a "found" smartphone with no service, running a Google Voice App on you neighbors' unsecured AP.

          • by wbr1 (2538558)
            Hmm, you live in an apartment with a basement, and a garage? Is perhaps your Mom's basement your apartment?
            • Probably an actual house being rented as an apartment? I've lived in a lot of places like that
            • It's a townhouse. Picture six tiny houses (with the basement and garage being the ground level floor) in a row and then squash them together into one building, each with it's own garage on the front and deck on the back. Nonetheless, it's still a rented apartment with all of the limitations of such (paint is the most permanent change we can make).

              It would be much nicer if it were my mom's basement and garage. Either one is twice the size of my entire apartment.

              • by wbr1 (2538558)
                I figured it was a townhouse. I in fact rent a basement apartment. But, making the miles basementnjokenwas far to easy. I couldn't resist.
          • by evilviper (135110)

            My landline only has two ports... one in the kitchen and one in the master bedroom.

            It's really not that difficult to install more phone jacks or other low-voltage wire drops in your home. In the best case, all you need is a bit of tape and some wire. In less common cases, you might need fish tape, a drill, and a saw if you don't have an existing box to reuse.

            They even make combination jacks with various quantities of phone/coax/ethernet/etc., jacks, so you usually don't need to make any more holes in your

      • by whois (27479)

        I would have rather seen radios that bonded on 4 40Mhz channels than one 160Mhz channel. Maybe the overhead is lower because you can do all your FEC at once, but it means you can't work around noise by grabbing two low 40Mhz and two high 40Mhz. Or even better if you could break it into 8 20Mhz channels.

        Maybe they're doing all or nothing because there is already so much overlap in 5Ghz than it's not worth frequency hopping or whatever, or maybe they're trying to keep the chip cost down so people can afford

        • by adri (173121) on Friday June 14, 2013 @04:58PM (#44011167) Homepage Journal

          The 802.11ac spec lets you do that.

          You can use 40, 80, 80+80 or 160. Right now I think everything is shipping 80 only, but I could be wrong. But the chip is allowed to transmit on whichever channel is free. If the primary 20MHz channel is free, it transmits on that. If the Primary and Extension 20Mhz channel are both free (ie, the "HT40" channel in 802.11n parlance) it transmits on that. If all 80MHz is free, it transmits on that.

          It's pretty nifty stuff.

      • by Sycraft-fu (314770) on Friday June 14, 2013 @05:11PM (#44011317)

        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.

        • by vlueboy (1799360)

          DECT 6.0 phones work on the 1900MHz band and more or less act like short-range cell phones.

          Seconded. I have a DECT 6.0 implementation that lets me bind up to 2 BT smartphones so that incoming calls ring at home. It's still pretty poor tech with an unacceptable lag and adds VOIP-like quality loss, but in theory would mitigate issues for those who leave the phone on Vibrate when it's misplaced.

          I'd love it if DECT 7.0 could replace the chiptune ringing. I mean, POTS's bell-less "Ring-Ring" tones are soooo 1990's... add smartphone ringtone cloning to my home base phones, and it will give the industry

      • by eggboard (315140)

        Outdated opinion on 5 GHz. The channels 149 and higher can broadcast at 20 times the signal strength of channels 36 to 48, and Apple and others have been boosting power progressively over the years. I can see it around me in my home and the last office I had: you can see a lot of 5 GHz now because of newer devices, where before, I only saw 2.4 GHz. That's anecdote, but fire up iStumbler or a Windows equivalent (aircrack-ng?) and see what I mean.

      • My cell phone does not operate on 5ghz

      • Cordless phones as in land lines? Few people under 40 have a land line and if you really need something besides a cell phone why not connect to that same wifi?

      • by Molochi (555357)

        I'm going to repeat this, because it didn't get +5 Informative (yet).

        5GHz (even802.11a) is best if your office/apartment shares a wall/ceiling/floors with neighbors. It doesn't penetrate as well as 2.4GHz and that means that your wifi isn't affected as much by your neighbors use of the spectrum.

        It does increase the need for repeaters to keep the bandwidth high on your own LAN, but you don't get screwed as much by the neighbors.

    • by jimbouse (2425428)
      As a wireless ISP owner, I dread all this 802.11ac gear. 80+mhz channels so that they can stream their AirPlay or whatever they *think* they need to see in HD.

      There is a finite amount of spectrum and every bozo is going to turn their router up to the max width and power because "more is better".

      /soapbox
      • by Anonymous Coward

        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.

      • by Bengie (1121981)
        AC uses beam-forming, so it should help that the wifi is directional.
      • by Bengie (1121981)
        It uses beam forming and should help a bit with noise.
      • by Bengie (1121981)
        I hope this isn't a dupe. /. has been mad at me. AC uses beam-forming, making it at least somewhat directional.
      • by omnichad (1198475)

        Correct me if I'm wrong, but since this is all on 5GHz how does this even affect you? Outdoor 5GHz implementations won't make it through exterior walls, and indoor 5GHz routers won't even reach outside to interfere.

    • by Anonymous Coward

      Greater speeds require more spectrum.

      More spectrum is the easiest way to get greater speeds, but things like MU-MIMO increase speeds without using more spectrum. Check out the article. It address everything you mentioned.

    • by sigipickl (595932)

      Yes and no. There is boatloads more space in the 5GHz spectrum, and as another person has already stated, 5GHz doesn't do well with solid objects, so the signal will not propagate nearly as far.

      Where .11ac is going to cause problems is when wave 2 of the standard hits the market in another year or two- 160MHz wide channels will eat up the available 5GHz spectrum real quick. We'll have multi-user MIMO with that release though, which will mean much more efficient use of the spectrum.

  • "In theory, there is no difference between theory and practice. In practice, there is."

    • I occasionally have someone ask me why their internet is so slow when there router says up to 300mbps or a gigabit all I can do is reply "yes but the internet is coming through your dsl modem at a much lower 6mbps".

  • 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.
  • by ArcadeMan (2766669) on Friday June 14, 2013 @04:03PM (#44010649)

    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.

    • That's not really a solution. Gigabit ethernet doesn't have a practical throughput of 1 Gb either.

      Oh, right, and sometimes there's a reason why people are using wireless.

      • Re:Simple solution (Score:5, Insightful)

        by Anonymous Coward on Friday June 14, 2013 @04:21PM (#44010833)

        Gigabit ethernet doesn't have a practical throughput of 1 Gb either.

        Yes it does, I've never seen any problems with pushing 1gig either at home or at work.
        Perhaps you're having problems with the backplane capacity of your router, or issues with your NIC or computer. But it's not the connection between the ports at fault, unless you've got the cable wound around a source of powerful RF emissions.

        • by klui (457783)

          Maybe the guy's cables are patched like this. http://i.imgur.com/jVbuPjTh.jpg [imgur.com]

      • Re:Simple solution (Score:4, Informative)

        by Bengie (1121981) on Friday June 14, 2013 @04:59PM (#44011191)
        I get 960Mb one direction and 1.6Gb bi-directional with my consumer-grade network at home. I also get 110MB/s+ over SMB with sub 1% cpu usage. 1Gb is not hard.
      • Yeah, that's nonsense. I regularly push 120MByte/sec (just under 1Gbps) over a variety of 1Gbps links. But it doesn't have to deal with significant noise or collisions, which are two of the speed losers. Also fairly reliable delivery (amount of loss is about 0.000000001%, and I'm not exaggerating) and its always 1Gbps, unlike Wifi which depends on channel bonding and signal quality for its base rate.

        Usually if you have 1gbps and can't saturate the link it's a bottleneck somewhere else - the source or destin

    • >Use ethernet. Cables don't have these kinds of problems.

      Yes they do. 802.3 has packet and medium access overhead. Just not as much as 802.11

      • by Anonymous Coward

        I'll say. 5-10% vs. 50-60% (comparison for me in real world usage). I put up with shaky/slow wifi in my office for 6 months before I finally ran CAT6. My gigabit connection is about 10-20x faster than my "150-300 Mbps" wifi connection was.

        • by MightyYar (622222)

          Same here - I just run CAT6 whenever possible. A couple of hours of fishing cables beats recurring wireless hiccups any day.

      • by AmiMoJo (196126) *

        I think he means that you don't have to share the available bandwidth with your neighbours. At least, hopefully not.

        • >I think he means that you don't have to share the available bandwidth with your neighbours.

          But you do. Your neighbors might not get to use your AP and internet connection, but they certainly occupy bandwidth on the wireless channel when they run their own equipment on the same channel.

  • And this is news? (Score:3, Informative)

    by holysin (549880) on Friday June 14, 2013 @04:08PM (#44010699) Homepage
    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.
    • by eggboard (315140)

      Now, c'mon, grizzled veteran (like myself?).

      The point of this article, which I wrote, is both to inform people of the practical aspects of 802.11ac, and also to deal with the disappointment. Average users, to whom these products are marketed in sound bites, may be upgrading because they think "faster is better!" This is to provide a realistic case for what 802.11ac will offer in Apple's version (and everyone's).

    • BREAKING NEWS: Tech veteran rips apart Apple's high speed claims

      Key word there is "Apple". It's a story involving $media_darling doing something that can be perceived to be wrong if you squint and tilt your head just so. Never mind that it's an industry standard that isn't deceptive or that Apple explains it using plain-written wording and simple, animated diagrams on their website. Media folks are going to take it and run with it because it drives hits, even if that wasn't Glenn Fleishman's intent with his

  • by TechyImmigrant (175943) on Friday June 14, 2013 @04:13PM (#44010747) Journal

    The school curriculum should be amended so that every school child graduates school knowing that physcial layer rate > MAC layer throughput.

    • by Sycraft-fu (314770) on Friday June 14, 2013 @05:17PM (#44011377)

      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.

      • So to clear up the confusion 802.11n rate specification should be "180mbps unless its higher, up to 300 or less".

        • 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.

  • by Anonymous Coward on Friday June 14, 2013 @04:17PM (#44010805)

    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.

  • 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

    • by fa2k (881632)

      Dropbox uses LAN sync when available. Granted, people don't usually stick gigabytes of stuff on dropbox and expect it to sync immediately, but it's still a bonus when it's fast.

  • I don't even.. (Score:4, Insightful)

    by Rytr23 (704409) on Friday June 14, 2013 @05:11PM (#44011319)
    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.
  • by Dwedit (232252) on Friday June 14, 2013 @05:11PM (#44011329) Homepage

    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.

    • Just thought I'd throw this out there since I was just testing it today. I have 802.11n gear (Airport Extreme, the 3x3 version with advertised 450 mbps speed). From 50ish feet away through a few walls I get 8 MB - 10 MB per second to my home server. That's getting up near 100 mbps which is good enough for me on wireless, but obviously nowhere near the 450 mbps that Windows claims my link speed to be.

      This is of course normal for wireless networking but I'd hope that 802.11ac gear would be able to do a b
  • 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...

  • 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.

  • 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?
    • by tlhIngan (30335)

      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?

      Well, not all AC devices will do 5GHz, like not all N devices do 5GHz. It's the difference between 802.11abgn and 802.11bgn devices (the 'a', representing 802.11a, only works on 5GHz, and there isn't a 5GHz N device

  • by pubwvj (1045960)

    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

  • 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.
  • 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 u

  • Apple is once again lying to people??? You mean the iPad isn't really "magical"??? /mind blown

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