Wi-Fi Slows Down over Time

Support & Help Requests
1

Hi there! Loving MATE 16.04. Question about internet connectivity, and I’m not sure if this is related to the problems Ubuntu 16.04 has in general with internet.

When I startup my machine, the internet is fast. 50mb/s, consistent with my colleagues using Windows machines in the office.

Beginning in about a half hour, it begins to slow. From 50mb/s to, to 30, to 12, eventually settles around 3mb/s, then in the end becomes completely unstable.

Usually doing sudo service network-manager restart will help restore, but the process starts all over. Sometimes a reboot is required. Sometimes it takes several reboots to get the process to start again.

Is this related to Ubuntu in general or MATE? This does NOT happen on Linux Mint 18. I’ve read about Ubuntu 16.04 internet problems, but not one like this.

If it is Ubuntu, is it being addressed in the point release this month? If not, I may sadly need to use Mint on my main machine. Can’t really take this anymore.

2

It’s likely a problem caused in the kernel. I myself have used wireless sticks in the past where its own driver just deteriorated the connection similar to what you’re experiencing.

The next point release for 16.04 may help address this should it ship a newer kernel.

You could tell us what wireless hardware you’re using:

inxi -i

You could find out which version the kernels are on Ubuntu MATE and again on Linux Mint:

uname -a

You could manually install a much newer kernel (or revert to an older one).

3

What wifi card are you using? Post the output of

lspci -nn

Is this related to Ubuntu in general or MATE?

No.

Post the output of

iwconfig your_wireless_interface

It should look somewhat like this:

box99@sys99:~$ iwconfig wlan0
wlan0     IEEE 802.11bg  ESSID:off/any  
          Mode:Managed  Access Point: Not-Associated   Tx-Power=20 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:off

I have seen problems with wireless cards failing at maximum power (20dBm in my case). Also have seen problems with Power Management.

Problems with wifi cards are usually specific to the Linux kernel version and do not really have much to do with the Linux distribution. If Mint works, what is the Linux kernel version there?

4

Thanks for your help, everyone!

Wireless card:

Network:   Card: Intel Wireless 7260 driver: iwlwifi
           IF: wlan0 state: up mac: 6c:29:95:42:49:f6
           WAN IP: 206.71.250.242 IF: wlan0 ip-v4: 10.1.1.223

Kernel (the special one for Chromebook Pixel 2):

Linux [MYNAME]-Samus 4.4.2ph+ #2 SMP Mon Feb 22 13:25:03 PST 2016 x86_64 x86_64 x86_64 GNU/Linux

Output of lspci -nn

00:00.0 Host bridge [0600]: Intel Corporation Broadwell-U Host Bridge -OPI [8086:1604] (rev 09)
00:02.0 VGA compatible controller [0300]: Intel Corporation Broadwell-U Integrated Graphics [8086:1616] (rev 09)
00:03.0 Audio device [0403]: Intel Corporation Broadwell-U Audio Controller [8086:160c] (rev 09)
00:14.0 USB controller [0c03]: Intel Corporation Wildcat Point-LP USB xHCI Controller [8086:9cb1] (rev 03)
00:1c.0 PCI bridge [0604]: Intel Corporation Wildcat Point-LP PCI Express Root Port #3 [8086:9c94] (rev e3)
00:1f.0 ISA bridge [0601]: Intel Corporation Wildcat Point-LP LPC Controller [8086:9cc3] (rev 03)
00:1f.2 SATA controller [0106]: Intel Corporation Wildcat Point-LP SATA Controller [AHCI Mode] [8086:9c83] (rev 03)
00:1f.6 Signal processing controller [1180]: Intel Corporation Wildcat Point-LP Thermal Management Controller [8086:9ca4] (rev 03)
01:00.0 Network controller [0280]: Intel Corporation Wireless 7260 [8086:08b1] (rev cb)

Output of iwconfig:

wlan0     IEEE 802.11abgn  ESSID:"Schweiger"  
          Mode:Managed  Frequency:5.745 GHz  Access Point: 8A:15:14:B5:7F:E0   
          Bit Rate=18 Mb/s   Tx-Power=22 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=36/70  Signal level=-74 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:11  Invalid misc:1181   Missed beacon:0
lo        no wireless extensions.
5

-74 dBm is mighty weak from your wireless router. I would expect -50 to -60 dBm over about 1000 sq feet. Also, there have been reports of the newer firmware for the Intel 7260 adapter reject some badly constructed beacon frames from some wireless routers. Over time, the link slows down and then disconnects. Sound familiar?

I don’t know anything about the special kernel for the Chromebook. Is this the same kernel that Mint is using?

You usually can find out what firmware is being loaded by looking through the dmesg.

dmesg | grep "[mM]icrocode\|firmware"