How can Ruckus R710 Deliver 800 Mbps on 2.4 Ghz ?

[vineet_tomar]

I have Ruckus R710 deployed in Office environment, Ruckus R710 is configured on Static Channel on 2.4 Ghz.
I connect 1 Laptop with R710 my Laptop gets associated on 144 Mbps speed and try to download a 3Gb file the MAX throughput i Get is 11MBps = 88Mbps.
I connect 2 Laptops with R710 and the Speed gets shared (Laptop1=5MBps / Laptop2=6MBPS)
I connect 3 Laptops with R710 and again Speed gets Shared (1=3, 2=5, 3=2).

What is Understand is total capaity on this Unit is 100 Mbps = 12.5 MBps

How can anyone use 800 Mbps ?? Because incase i have 20 Client connected speed will be shared from 100 Mbps.

[jake_shehan]

What type of laptops are you using? How many spatial streams do they support?

What throughput does this office get from their ISP? The Ruckus gear can only go as fast as the pipe that is feeding it if you are judging the performace based on what you have above. 

What channel size are you using on the 2.4 Radio? 800Mbps is not in real world applications but for you to improve what you are currently seeing I would recommend to set the channel width to 40MHz, you also mentioned that you have this set on a static channel, did you let the AP choose that based on the interference or did you assign it manually?  

[john_d]

88mbit is actually pretty good from 2.4GHz. The Ruckus calculation of 800mbit is based off peak theoretical throughput for:

  - 4x4:4 client
  - 256-QAM on 2.4GHz
  - 40MHz channel


This is a standard industry practice to advertise peak theoretical throughput on each band, but in reality, each of those 3 points are not really feasible, because:

 - 4x4:4: I don't know of any desktop or laptop, much less smartphone, that's got 4 MIMO radios. 3x3:3 is what you tend to find, and 2x2 is still popular for tablets and small laptops. So, this will cost you 50% or 75% of your max advertised capacity.
 - 256QAM on 2.4GHz is supported by a few Broadcom and Atheros chipsets (Broadcom calls it TurboQAM). Most other clients only support 64QAM (e.g. 300/450/600mbit 802.11n for 2, 3, and 4 streams respectively). In reality, you are unlikely to see a client that supports this extension, and also, this rate requires such good signal integrity that in a real world moderate-to-heavy density environment, it probably won't be usable.
 - 40MHz channels on 2.4GHz are basically impossible to use. Here's a good article that explains why: http://www.smallnetbuilder.com/wireless/wireless-features/31743-bye-bye-40-mhz-mode-in-24-ghz-part-1 Basically, it uses too much of the 2.4GHz spectrum (basically 2/3 of it), and causes so much potential interference that devices are allowed by protocol to advertise themselves being 40MHz-intolerant, and almost all devices do that... which in turn means the AP can never really use that width.


And finally, 2.4GHz penetrates so well through walls, and with only 3 truly nonoverlapping channels, you are almost surely going to see some level of interference in a real world test. Not to mention devices such as bluetooth, Zigbee, and even baby monitors share this frequency.


I think the 100mbit you're seeing on 2.4GHz is actually excellent. In my apartment with 80 neighboring AP's, I am lucky if I see 30-40mbit from a 3-stream 2.4GHz client. To truly get 100+mbit wifi reliably using ANY equipment, you will really have to rely on 5GHz.



P.S. The 2.4GHz radios in Ruckus AP's are really some of the best I've seen. I bought some consumer stuff that can't even maintain a connection on 2.4GHz in my high-interference dwelling.

P.P.S. Also, the "mbits" you see advertised for wifi are actually for signaling rate not data throughput rate. In reality, even with zero interference in the air, wifi is somewhere around 1/2 to 2/3 efficient. That is, 2 bits of data for every 3 bits transmitted in the air. That's just signaling / protocol overhead, not even counting TCP/UDP protocol overhead. So even the peak theoretical 800mbit only results in something like 400-500mbit of visible throughput in ideal conditions with ideal clients.

[bobby_wittenber]

Well put!