Sfdwhf

I am having problems with my wireless adapter on Ubuntu 14.04. Sometimes when I boot the computer it is able to establish a connection, maybe one fifth of the time, but mostly it is just trying to connect forever:

 % nmcli nm

RUNNING         STATE           WIFI-HARDWARE   WIFI       WWAN-HARDWARE   WWAN      

running         connecting      enabled         enabled    enabled         disabled 

Even when it is able to establish a connection there are problems. After a long uptime the connection seems to get congested and is often dropped. The same thing happens if I try to stream video or download large files.

My current hardware setup is somewhat peculiar. I spilled soda all over my other laptop, ruining the motherboard, so I decided to put this hard drive into my old one (the one I am currently on) in order to keep all my files and settings. Everything worked right away except for the wifi.

On that old machine I had noticed problems with the wireless connection under low signal strength. I solved that problem by downgrading and putting the bcmwl-kernel-source on hold using apt-mark. But that option doesn't seem to exist for my current drivers. I have since purged the obsolete drivers to make sure there is no conflict, but that had no effect on the problem.

Other threads prompted my to try the following, but to no avail:

sudo apt-get install --reinstall linux-firmware

sudo modprobe -r iwlwifi

sudo modprobe iwlwifi

System info:

 % sudo lshw -C network

  *-network

       description: Wireless interface

       product: Centrino Wireless-N 2230

       vendor: Intel Corporation

       physical id: 0

       bus info: pci@0000:02:00.0

       logical name: wlan0

       version: c4

       serial: 60:6c:66:32:96:f5

       width: 64 bits

       clock: 33MHz

       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless

       configuration: broadcast=yes driver=iwlwifi driverversion=4.2.0-35-generic firmware=18.168.6.1 latency=0 link=no multicast=yes wireless=IEEE 802.11bgn

       resources: irq:33 memory:f7d00000-f7d01fff

 % rfkill list                                                                                 

1: phy0: Wireless LAN

    Soft blocked: no

    Hard blocked: no

2: asus-wlan: Wireless LAN

    Soft blocked: no

    Hard blocked: no

3: asus-bluetooth: Bluetooth

    Soft blocked: yes

    Hard blocked: no

 % dmesg | grep iwl                                                                                       

[    9.487676] iwlwifi 0000:02:00.0: can't disable ASPM; OS doesn't have ASPM control

[    9.514737] iwlwifi 0000:02:00.0: loaded firmware version 18.168.6.1 op_mode iwldvm

[    9.566860] iwlwifi 0000:02:00.0: CONFIG_IWLWIFI_DEBUG disabled

[    9.566863] iwlwifi 0000:02:00.0: CONFIG_IWLWIFI_DEBUGFS enabled

[    9.566865] iwlwifi 0000:02:00.0: CONFIG_IWLWIFI_DEVICE_TRACING enabled

[    9.566868] iwlwifi 0000:02:00.0: Detected Intel(R) Centrino(R) Wireless-N 2230 BGN, REV=0xC8

[    9.566968] iwlwifi 0000:02:00.0: L1 Enabled - LTR Disabled

[    9.630114] ieee80211 phy0: Selected rate control algorithm 'iwl-agn-rs'

[   10.361252] iwlwifi 0000:02:00.0: L1 Enabled - LTR Disabled

[   10.368831] iwlwifi 0000:02:00.0: Radio type=0x2-0x0-0x0

[   10.613667] iwlwifi 0000:02:00.0: L1 Enabled - LTR Disabled

[   10.621565] iwlwifi 0000:02:00.0: Radio type=0x2-0x0-0x0

 % sudo iwlist wlan0 scan                                                                                                    

wlan0     Scan completed :

          Cell 01 - Address: A0:21:B7:AC:C1:3C

                    Channel:11

                    Frequency:2.462 GHz (Channel 11)

                    Quality=39/70  Signal level=-71 dBm  

                    Encryption key:on

                    ESSID:"JsNet"

                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s

                              9 Mb/s; 12 Mb/s; 18 Mb/s

                    Bit Rates:24 Mb/s; 36 Mb/s; 48 Mb/s; 54 Mb/s

                    Mode:Master

                    Extra:tsf=000000001928e67b

                    Extra: Last beacon: 32ms ago

                    IE: Unknown: 00054A734E6574

                    IE: Unknown: 010882848B960C121824

                    IE: Unknown: 03010B

                    IE: IEEE 802.11i/WPA2 Version 1

                        Group Cipher : CCMP

                        Pairwise Ciphers (1) : CCMP

                        Authentication Suites (1) : PSK

                    IE: Unknown: 2A0100

                    IE: Unknown: 32043048606C

                    IE: Unknown: DD180050F2020101830003A4000027A4000042435E0062322F00

                    IE: Unknown: DD1E00904C33CC111BFFFF000000000000000000000000000000000000000000

                    IE: Unknown: 2D1ACC111BFFFF000000000000000000000000000000000000000000

                    IE: Unknown: DD1A00904C340B001B00000000000000000000000000000000000000

                    IE: Unknown: 3D160B001B00000000000000000000000000000000000000

                    IE: Unknown: DD0900037F01010000FF7F

                    IE: Unknown: DD0A00037F04010002004000

                    IE: Unknown: DD860050F204104A0001101044000102103B0001031047001000000000000010000000A021B7ACC13C1021000D4E6574676561722C20496E632E10230008574E4452333730301024000456314831104200046E6F6E651054000800060050F204000110110017574E445233373030763228576972656C65737320415029100800020086103C000103

 % sudo iw wlan0 scan                                                                                                        

BSS a0:21:b7:ac:c1:3c (on wlan0)

    TSF: 742840547 usec (0d, 00:12:22)

    freq: 2462

    beacon interval: 100

    capability: ESS Privacy ShortPreamble ShortSlotTime (0x0431)

    signal: -71.00 dBm

    last seen: 0 ms ago

    SSID: JsNet

    Supported rates: 1.0* 2.0* 5.5* 11.0* 6.0 9.0 12.0 18.0 

    DS Parameter set: channel 11

    RSN: * Version: 1

         * Group cipher: CCMP

         * Pairwise ciphers: CCMP

         * Authentication suites: PSK

         * Capabilities: (0x0000)

    ERP: <no flags>

    Extended supported rates: 24.0 36.0 48.0 54.0 

    WMM: * Parameter version 1

         * u-APSD

         * BE: CW 15-1023, AIFSN 3

         * BK: CW 15-1023, AIFSN 7

         * VI: CW 7-15, AIFSN 2, TXOP 3008 usec

         * VO: CW 3-7, AIFSN 2, TXOP 1504 usec

    HT capabilities:

        Capabilities: 0x11cc

            HT20

            SM Power Save disabled

            RX HT40 SGI

            TX STBC

            RX STBC 1-stream

            Max AMSDU length: 3839 bytes

            DSSS/CCK HT40

        Maximum RX AMPDU length 65535 bytes (exponent: 0x003)

        Minimum RX AMPDU time spacing: 8 usec (0x06)

        HT RX MCS rate indexes supported: 0-15

        HT TX MCS rate indexes are undefined

    HT operation:

         * primary channel: 11

         * secondary channel offset: no secondary

         * STA channel width: 20 MHz

         * RIFS: 0

         * HT protection: non-HT mixed

         * non-GF present: 0

         * OBSS non-GF present: 1

         * dual beacon: 0

         * dual CTS protection: 0

         * STBC beacon: 0

         * L-SIG TXOP Prot: 0

         * PCO active: 0

         * PCO phase: 0

    WPS: * Version: 1.0

         * Wi-Fi Protected Setup State: 2 (Configured)

         * Response Type: 3 (AP)

         * UUID: 00000000-0000-1000-0000-a021b7acc13c

         * Manufacturer: Netgear, Inc.

         * Model: WNDR3700

         * Model Number: V1H1

         * Serial Number: none

         * Primary Device Type: 6-0050f204-1

         * Device name: WNDR3700v2(Wireless AP)

         * Config methods: Ethernet, Label, PBC

         * RF Bands: 0x3

First, check the settings in the router. WPA2-AES is preferred; not any WPA and WPA2 mixed mode and certainly not TKIP. Second, if your router is capable of N speeds, you may have better connectivity with a channel width of 20 MHz in the 2.4 GHz band instead of automatic 20/40 MHz, although it is likely to affect N speeds. I also have better luck with a fixed channel, either 1, 6 or 11, rather than automatic channel selection. Also, be certain the router is not set to use N speeds only; auto B, G and N is preferred. After making these changes, reboot the router.

Next, I recommend that your regulatory domain be set explicitly. Check yours:

sudo iw reg get

If you get 00, that is a one-size-maybe-fits-all setting. Find yours here: http://en.wikipedia.org/wiki/ISO_3166-1_alpha-2 Then set it temporarily:

sudo iw reg set IS

Of course, substitute your country code if not Iceland. Set it permanently:

gksudo gedit /etc/default/crda

Use nano or kate or leafpad if you don't have the text editor gedit.

Change the last line to read:

REGDOMAIN=IS

Proofread carefully, save and close the text editor.

Next, I'd set IPv6 to Ignore in Network Manager: http://docs.fedoraproject.org/en-US/Fedora/18/html/Installation_Guide/images/netconfig/network-connections-ipv6-ignore.png This example is for ethernet, but you want wireless.

If these changes do not help, please try:

sudo modprobe -r iwlwifi

sudo modprobe iwlwifi 11n_disable=8

If it helps, make it permanent:

sudo -i

echo "options iwlwifi 11n_disable=8"  >>  /etc/modprobe.d/iwlwifi.conf

exit