300Mbps Wireless USB on 150Mbps Router getting only 50Mbps speed

[Thee]

Hey

I need some help, I know Wireless speeds are lower in real world then advertised, but I really expected at least 100Mbps ...

My hardware:
D-Link DIR-600 (with latest firmware)
D-Link DWA-131 Wireless N USB adapter

My router supports up to 150Mbps, and the USB adpter 300Mbps, so the speeds should be good, but I'm only getting around 50Mbps (on Ubuntu, on Windows I get around 40Mbps)
The distance from the router to the USB adapter is like 1 meter. And there are no objects in between, except my desk.

So regardless of the OS, Im getting really low speeds. Anyone got any tips, because all I got on google search is that wireless sucks.
My router settings are attached.

Thanks

wireless.jpg

[TheFu]

Wifi sucks. There are lots of issue with it. Interference can be a big one. That is highly localized. Antenna design and deployment is more complex than most people appreciate. Being a few inches off of the broadcast cneter for an antenna can make huge differences. Also, each vendor many not implement the "standard" in the same way, so they all slow down. The number of devices on the network effectively halves the bandwidth and whatever the slowest device connect is becomes the upper limit on bandwidth for everyone. Don't use a microwave and any 2.4Ghz cordless phones nearby either.

Why do you have it set to high power? That messes with the SNR negatively. Also, why not let it auto select the best channel and speed? I see you are force N-only - THAT is good.

What is the bandwidth limitation of USB2? Isn't is 40Mbps .... and that is the theory, so in reality, it becomes somewhere south of 30Mbps. Or is that MBps?

I know that my wifi-N wireless card inside my laptop was the cheapest one and doesn't even support 75Mbps. I should have paid the $15 for an upgraded version, which would have gotten me to 300Mbps.

I've never been impressed with d-link. Then again, I've never been impressed with most wifi except Ubiquiti WAPs.

I'd also point out that greater speeds only matters for your internal LAN. Most broadband connections are 30Mbps or less and most internet servers will throttle fast connections to 1-2Mbps to be fair with all their users.

Wifi sucks.

[Thee]

I know the speed is as slow as the slowest client, but I only have this one connected, rest of the computers are connected via ethernet and I would connect this one too if I had more ethernet slots on the router, and a switch I dont wanna buy yet when I have this wifi adapter laying around.

Why do you have it set to high power? That messes with the SNR negatively. Also, why not let it auto select the best channel and speed? I see you are force N-only - THAT is good.

Power I did not change, I think it was set like that by default. What should i choose? Medium or Low?
Ill try with auto settings and see where that gets me, but I think it wont matter much.

I'd also point out that greater speeds only matters for your internal LAN. Most broadband connections are 30Mbps or less and most internet servers will throttle fast connections to 1-2Mbps to be fair with all their users.

Actually I have a 50Mbps internet connection, so with speeds that this wifi adapter gives me, I'm not even capping my internet speed It goes up to 52mbps on ethernet. And I was thinking of getting 100mpbs internet connection in the future...

Thanks for the reply!

EDIT: Channel set to Auto / Transmission rate set to Auto / Power set to Low = speed is 25Mbps now ...

[tgalati4]

Install iperf. Run iperf -s on one desktop machine and iperf client on the wireless to get some statistics.

I normally get 20 MB/sec using wirelss-G, but when netflix is streaming in another room it drops:

tgalati4@Mint14-Extensa ~ $ iperf -c tubuntu2 -w 1024k -i 2 -t 20
------------------------------------------------------------
Client connecting to tubuntu2, TCP port 5001
TCP window size: 256 KByte (WARNING: requested 1.00 MByte)
------------------------------------------------------------
[ 3] local 192.168.1.103 port 48497 connected with 192.168.1.114 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0- 2.0 sec 2.12 MBytes 8.91 Mbits/sec
[ 3] 2.0- 4.0 sec 2.50 MBytes 10.5 Mbits/sec
[ 3] 4.0- 6.0 sec 3.25 MBytes 13.6 Mbits/sec
[ 3] 6.0- 8.0 sec 2.75 MBytes 11.5 Mbits/sec
[ 3] 8.0-10.0 sec 2.75 MBytes 11.5 Mbits/sec
[ 3] 10.0-12.0 sec 2.50 MBytes 10.5 Mbits/sec
[ 3] 12.0-14.0 sec 3.25 MBytes 13.6 Mbits/sec
[ 3] 14.0-16.0 sec 3.38 MBytes 14.2 Mbits/sec
[ 3] 16.0-18.0 sec 3.00 MBytes 12.6 Mbits/sec
[ 3] 18.0-20.0 sec 2.75 MBytes 11.5 Mbits/sec
[ 3] 0.0-20.1 sec 28.4 MBytes 11.8 Mbits/sec

Reverse the connection and go from the desktop to the wireless to see if there is a difference.

With all of the physical, electrical, and software layers, it's amazing that any of this stuff works at all.

[TheFu]

Actually I have a 50Mbps internet connection, so with speeds that this wifi adapter gives me, I'm not even capping my internet speed It goes up to 52mbps on ethernet. And I was thinking of getting 100mpbs internet connection in the future...

The total available internet bandwidth helps, but very few servers on the internet will push data that fast. Most will throttle users to 1-2Mbps. OTOH, being able to have 30+ connects that are each throttled to 1-2Mbps is pretty great. I had a really fast connection like yours a few years ago, but it didn't make much real difference, so I dropped back to a 12/3 connection and got more public IPs instead.

Could you run similar tests with exactly the same equipment over wired ethernet? Perhaps there is something else getting in the way, like a slow HDD?

Sorry that I'm not much help.

[Thee]

Here are the results:

Desktop > WIFI


[  3] local 192.168.0.104 port 40646 connected with 192.168.0.101 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 2.0 sec  7.25 MBytes  30.4 Mbits/sec
[  3]  2.0- 4.0 sec  6.75 MBytes  28.3 Mbits/sec
[  3]  4.0- 6.0 sec  5.25 MBytes  22.0 Mbits/sec
[  3]  6.0- 8.0 sec  6.25 MBytes  26.2 Mbits/sec
[  3]  8.0-10.0 sec  6.38 MBytes  26.7 Mbits/sec
[  3] 10.0-12.0 sec  4.88 MBytes  20.4 Mbits/sec
[  3] 12.0-14.0 sec  5.50 MBytes  23.1 Mbits/sec
[  3] 14.0-16.0 sec  4.75 MBytes  19.9 Mbits/sec
[  3] 16.0-18.0 sec  4.50 MBytes  18.9 Mbits/sec
[  3] 18.0-20.0 sec  5.12 MBytes  21.5 Mbits/sec
[  3]  0.0-20.1 sec  56.8 MBytes  23.7 Mbits/sec




WIFI > Desktop


[  3] local 192.168.0.101 port 37479 connected with 192.168.0.104 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 2.0 sec  7.75 MBytes  32.5 Mbits/sec
[  3]  2.0- 4.0 sec  7.75 MBytes  32.5 Mbits/sec
[  3]  4.0- 6.0 sec  7.75 MBytes  32.5 Mbits/sec
[  3]  6.0- 8.0 sec  8.12 MBytes  34.1 Mbits/sec
[  3]  8.0-10.0 sec  8.25 MBytes  34.6 Mbits/sec
[  3] 10.0-12.0 sec  8.00 MBytes  33.6 Mbits/sec
[  3] 12.0-14.0 sec  8.50 MBytes  35.7 Mbits/sec
[  3] 14.0-16.0 sec  8.12 MBytes  34.1 Mbits/sec
[  3] 16.0-18.0 sec  7.75 MBytes  32.5 Mbits/sec
[  3] 18.0-20.0 sec  7.38 MBytes  30.9 Mbits/sec
[  3]  0.0-20.0 sec  79.5 MBytes  33.3 Mbits/sec


-----


Desktop > WIFI (This time WIFI disabled and connected via ethernet)

[  3] local 192.168.0.104 port 40654 connected with 192.168.0.101 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 2.0 sec  22.5 MBytes  94.4 Mbits/sec
[  3]  2.0- 4.0 sec  22.5 MBytes  94.4 Mbits/sec
[  3]  4.0- 6.0 sec  22.5 MBytes  94.4 Mbits/sec
[  3]  6.0- 8.0 sec  22.4 MBytes  93.8 Mbits/sec
[  3]  8.0-10.0 sec  22.5 MBytes  94.4 Mbits/sec
[  3] 10.0-12.0 sec  22.4 MBytes  93.8 Mbits/sec
[  3] 12.0-14.0 sec  22.5 MBytes  94.4 Mbits/sec
[  3] 14.0-16.0 sec  22.4 MBytes  93.8 Mbits/sec
[  3] 16.0-18.0 sec  22.5 MBytes  94.4 Mbits/sec
[  3] 18.0-20.0 sec  22.4 MBytes  93.8 Mbits/sec
[  3]  0.0-20.0 sec   225 MBytes  94.1 Mbits/sec




WIFI > Desktop (This time WIFI disabled and connected via ethernet)

[  3] local 192.168.0.101 port 37485 connected with 192.168.0.104 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 2.0 sec  22.6 MBytes  94.9 Mbits/sec
[  3]  2.0- 4.0 sec  22.4 MBytes  93.8 Mbits/sec
[  3]  4.0- 6.0 sec  22.5 MBytes  94.4 Mbits/sec
[  3]  6.0- 8.0 sec  22.4 MBytes  93.8 Mbits/sec
[  3]  8.0-10.0 sec  22.5 MBytes  94.4 Mbits/sec
[  3] 10.0-12.0 sec  22.5 MBytes  94.4 Mbits/sec
[  3] 12.0-14.0 sec  22.4 MBytes  93.8 Mbits/sec
[  3] 14.0-16.0 sec  22.5 MBytes  94.4 Mbits/sec
[  3] 16.0-18.0 sec  22.4 MBytes  93.8 Mbits/sec
[  3] 18.0-20.0 sec  22.5 MBytes  94.4 Mbits/sec
[  3]  0.0-20.0 sec   225 MBytes  94.2 Mbits/sec

So I think we can rule out every hardware as a possible problem, except the WIFI.

[TheFu]

Install iperf. Run iperf -s on one desktop machine and iperf client on the wireless to get some statistics.

I normally get 20 MB/sec using wirelss-G, but when netflix is streaming in another room it drops:

This is due to multiple devices sharing the same frequencies. A rough estimate for the impact is to reduce the theoretical bandwidth by 50% for every device on the channel.
0 Dev = 150 Mbps
1 Dev = 75 Mbps
2 Dev = 37.5 Mbps
3 Dev = 18.75 Mbps

So, with 2 devices connected to a wifi-150 AP, both can expect throughput of about 38Mbps.
We aren't talking active use, just being connected impacts.

Of course, you can deploy TDMA APs (like Ubiquiti) and get higher throughput, but most home users and small businesses will not bother.

Could there be other wifi devices on your network? Smartphone, tablet?

[Thee]

No, absolutely nothing is running on WIFI except that one.

I have:
2 desktop PCs
1 Raspberry Pi
1 Laptop
1 NAS device
And except that one desktop, everything else is connected via ethernet.

[TheFu]

What do your neighbors have that could be interfering? If you live on less than 3 acres, interference can be a problem.

My neighbors don't seem to understand that there are only 3 non-overlapping wifi-G channels in the USA. 1, 6, 11. Every other channel overlaps with 1 or 2 of those, so picking anything other than those is just going to slow everyone down.

[pierceTN]

If you only have 50 Mbps going into your wifi router, then your not going to get any more out of it over wifi. If it is interference, than you will be having intermittent issues as well.

Try plugging directly in to your Ethernet cable that is plugged into the internet port in your router, then run a few speed tests. (like, speedtest[dot]net) then unplug, and connect to your wifi router through wireless and run a few, then compare the speed between the hardwired, and wireless. If they are about the same (give or take about 10%) then it is not going to be a wireless problem.

also, make sure you have a good connection signal to your router, it could be that your router is out of range, (i.e. distance, brick wall, etc...).


And like others have said, it could be interference from other radios on the same frequency.This will most likely happen when you live in a neighborhood. If you see what channels other routers are on then you can set yours to a different channel to avoid interference.



Hope that helps some,


-Pierce