Baffled by intermittent slow wifi internet

mrpringle · 2014-08-25 10:32:03

Hi,
It seems my laptop running arch linux with an Intel Wireless 7260 network adapter is having issues with intermittent slow internet connectivity via wifi.

I think I can reliably reproduce this problem after a reboot. I've tried running speed tests using my ISP mirror and get speeds like 200KB/s, when I should be getting > 1MB/s.

This is what I've tried to rule out other issues.
Using wifi on my phone I consistently see speeds > 1MB/s.
I've moved my laptop close to the wireless AP when running tests, the signal is good.
When I plug an Ethernet cable into my laptop I do not observe these sub par speeds - even straight after a reboot.
If I run iperf from the laptop wireless interface to a PC connected to wireless AP via Ethernet I see good speeds: 30MB/s to 50MB/s.

This problem only came about quite recently. Possibly after a kernel update but I don't keep track of these things.

I'm quite baffled because the behaviour I'm observing doesn't seem to make any sense. It is making things like youtube and xbmc quite often unusable because buffering is so slow.

Pse · 2014-08-26 02:46:51

Is QoS enabled on the router? I've seen this with routers that set a wrong max throughput for QoS packets. If you can, disable QoS temporarily to test.

mrpringle · 2014-09-05 07:55:29

I thought I replied but apparently not. I can't find QoS settings on the router. I've figured out that when the internet is slower than usual and I run iperf to another PC inside my LAN that seems to fix the slowness issue. It all seems very bizarre to me but the problem is consistently reproducible.

brebs · 2014-09-05 08:13:34

mrpringle wrote:

get speeds like 200KB/s, when I should be getting > 1MB/s.

I had the same problem, which was fixed by replacing a wireless Intel 5100 card for a 5300 card.

Seemed to be a hardware problem.

ratcheer · 2014-09-05 13:31:12

I had a problem similar to that a few days ago. In my case, I discovered that my router had assigned my Arch system's static IP to another device. Choosing an unused IP solved it.

I still have not figured out how to reserve an IP on that router, even though I have done so many times on other routers.

Tim

mrpringle · 2014-09-05 14:29:55

Thanks for the suggestions. I decided to try installing the lts kernel because this problem only seemed to come about recently. I was running linux-3.16.1-1 and installed linux-lts-3.14.17-1 and after that everything is running smoothly.

I've flipped between the lts and base kernel a couple of times just to verify the behaviour is consistent.

I'll stick with the lts kernel from now on

Arch Linux

#1 2014-08-25 10:32:03

Baffled by intermittent slow wifi internet

#2 2014-08-26 02:46:51

Re: Baffled by intermittent slow wifi internet

#3 2014-09-05 07:55:29

Re: Baffled by intermittent slow wifi internet

#4 2014-09-05 08:13:34

Re: Baffled by intermittent slow wifi internet

#5 2014-09-05 13:31:12

Re: Baffled by intermittent slow wifi internet

#6 2014-09-05 14:29:55

Re: Baffled by intermittent slow wifi internet

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