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.'"

Re:wasteful on spectrum

[phizi0n]

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.

And this is news?

[holysin]

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.

Re:wasteful on spectrum

[MightyYar]

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

Re:wasteful on spectrum

[adri]

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.

Re:Simple solution

[Bengie]

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.

These days phones are going to 1900MHz

[Sycraft-fu]

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.

The problem is that you see different ones spec'd

[Sycraft-fu]

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.

Re:wasteful on spectrum

[exodus2]

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