Ubuntu – Wireless with WEP extremely slow on an Acer Timeline 4810T with a Centrino Wireless-N 1000

intel-wirelessSecuritywireless

I've upgraded an Acer Timeline 4810T to Ubuntu 11.10. Everything works fine except for the darn wireless interface (network manager).

I just tested the wireless interface over a non-encrypted signal and it works beautifully. The issue is definitely related to WEP.

Unfortunately, some of the networks I need to connect to are WEP encrypted, therefore this is a serious issue for me that is preventing me from using Ubuntu on my laptop.

This was no problem in 11.04 and prior. Is there a simple solution for this?
Any suggestions?

Here's more hardware information. Hopefully this helps to debug the network issue:

sudo lshw -class network

  *-network
       description: Wireless interface
       product: Centrino Wireless-N 1000
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:02:00.0
       logical name: wlan0
       version: 00
       serial: 00:1e:64:3c:5e:e0
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlagn driverversion=3.0.0-13-generic-pae firmware=39.31.5.1 build 35138 latency=0 link=no multicast=yes wireless=IEEE 802.11bgn
       resources: irq:43 memory:d2400000-d2401fff

lspci

02:00.0 Network controller: Intel Corporation Centrino Wireless-N 1000

rfkill list

0: phy0: Wireless LAN
    Soft blocked: no
    Hard blocked: no
1: acer-wireless: Wireless LAN
    Soft blocked: no
    Hard blocked: no

Many thanks for your help!

I just tested the wireless interface over a non-encrypted signal and it works beautifully.

The issue is definitely related to WEP.

Unfortunately, some of the networks I need to connect to are WEP encrypted, therefore this is a serious issue for me that is preventing me from using Ubuntu on my laptop.

Blacklisting acer-wmi module didn't have any noticeable effect and I reverted the change after testing.

blacklist acer-wmi

========

The following fix, suggested by Bruno, works:

options iwlagn 11n_disable=1

I did not go any further and did not try the second option provided.

Best Answer

Edit the file (or create) /etc/modprobe.d/options.conf, add the line. If the file doesn't exist create it by doing:

sudoedit /etc/modprobe.d/options.conf

The system will then ask for your password and create this file. Then you need to add this line to it. 

options iwlagn 11n_disable=1

or 

options iwlagn 11n_disable50=1

Try each and see which works for you.

Reboot for testing on each line you are testing

sudo reboot

This will disable your N rated wireless access and connect it only with G speeds, if it works you are suffering a known bug (have to look the report for you, drop a comment if this worked). It wont be as fast as connection to a N rated wireless but at least will work.

If none of the 2 lines works for you just remove them to revert the effects.

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