Extremely Slow Wifi Speeds After Installing Ubuntu

The other day I decided to install Ubuntu 11.10 Oneiric Ocelot nativly on my Dell Studio 1737 laptop. Everything went great except for one thing. When it came time to connect to the Internet or any network resource for that matter I was reminded of the days of dial up in that things were VERY slow. The problem seems to be with the iwlagn module produced by the iwlwifi Linux kernel driver which supports several Intel wireless LAN adapters. There would seem to be a bug in it causing a huge speed decrease when conneted to a 802.11n network. The only solutions I found was to do one of the following things:

Disable 802.11n  and downgrade to g on your wireless access point.

 (Not an exceptable answer to me due to the fact I have other products running n that have no issues. Why should I suffer on these devices because my laptop fails to run on it.)

And the other solution I was able to hunt down which is the one I am using until a fix for the issue surfaces which involves forcing iwlagn to not use n. Before making the change permanant run the following commands from a console window. The commands will disable n on the device without making it a permanant change to see if this fix will actually work for you before editing files. If this solution don’t work a simple reboot will bring you back to where you were.

sudo rmmod iwlagn
sudo modprobe iwlagn 11n_disable=1

If after running the above commands you notice greatly improved speeds then you can make them permanent by doing the following.

sudo nano /etc/modprobe.d/options.conf

Then add the following line to this file.

options iwlagn 11n_disable=1