WiFi Causing Ping Spikes

[jhewess]

Hi,

A bit of background first... I'm on Plusnet fibre, and use a 7800DXL along with the Openreach ECI modem. I've noticed on my TBB BQM that every six hours or so I would get ping spikes that last for around an hour. This started happening suddenly on Tues 3rd Feb, no settings had been changed at all. See below graph for an example of spikes:



Here you can see spikes at around 5am, 11am, 4pm, and 10pm.

It's taken a bit of head scratching, but with the assistance of someone else on Plusnet that is using the 8800NL, and who is also experiencing these spikes, we've narrowed it down to the WiFi causing the issues. I've tried everything that I can think of to test this out. I know that it's nothing on my network causing the spikes, as I've previously unplugged every wired device, and deactivated every wireless device overnight to see what would happen, but the spikes were still there. Also, we went away for a few days last week, so nothing on the network was active or being used, and the spikes were still there (see below graph)


I updated to the latest 2.32d.dm12 over the weekend which made no difference. It was previously on 2.32d. I've also tried a factory reset and changing the SSID's and WiFi passwords as a precaution.
Since learning that it could be WiFi related, I tested turning off the wifi to see what would happen. See the below graph:

In this graph the 5g wifi was turned off at approx 10.30pm. I left the 2.4g on overnight to see what would happen. Sure enough, there's a spike just before 2am. I then turned off the 2.4g as well just before I left for work at around 7.15am, and for the rest of the day the graph has been clear.

I've now turned the 5g back on, as I'm curious to see what band is causing the spikes. Also, when I plug the Plusnet supplied Technicolor router back in, there is no evidence of any spikes. I did wonder if it might be something causing interference, but with it starting so suddenly, and nothing changing with any router settings or in the house, nor with it effecting the Technicolor, I've pretty much ruled this out.

Has anyone got any ideas of what might be causing this? Are there any settings that could be changed or tweaked?

[Tomken]

What are the default MTU settings in the PlusNet router compared to the 7800DXL and what is your computer set at.

You can check your computer's setting (which is likely to be 1500) by opening a command prompt as an administrator and entering -

netsh int ipv4 show interfaces

You don't need an admin command prompt for that command but you will to change the computer's settings.

Your computer should match what your router is using and you can change the setting with this command using the Idx number for whichever adapter you are using.

Assuming it's 12 for the Wireless and changing the MTU to 1492

netsh int ipv4 set subinterface 12 mtu=1492 store=persistent

Then repeat the ....show interfaces command again to confirm.

As the ISP's MTU setting isn't a one size fits all, you can run TCP Optimizer which will give you the best setting for your connection but both the router and computer must be set to 1500 first, but it's good for only up to Win 7 http://www.speedguide.net/downloads.php

You can also do it manually through the command prompt if that program isn't supported by your OS or if you want to see what's going on. http://www.sevenforums.com/tutorials/94 ... limit.html

[jhewess]

1492 on both routers, and on the PC. Checked the PC a couple of weeks ago and matched it up then just incase this might be an issue. The PC is wired. Also I'm connecting via PPPoE on the Ewan, and the 7800dxl will only go as high as 1492 because of this. I couldn't set it at 1500 even if I wanted to.

[billion_fan]

1492 on both routers, and on the PC. Checked the PC a couple of weeks ago and matched it up then just incase this might be an issue. The PC is wired. Also I'm connecting via PPPoE on the Ewan, and the 7800dxl will only go as high as 1492 because of this. I couldn't set it at 1500 even if I wanted to.

Has the spike occurred since the 5G band has been enabled?

[jhewess]

After testing over night with just the 5g band enabled, the spikes are much more pronounced. With both bands enabled, even more so. So bizarre as, like I said in my first post, it only suddenly started happening at the beginning of the month, and the other router's not effected.

[billion_fan]

After testing over night with just the 5g band enabled, the spikes are much more pronounced. With both bands enabled, even more so. So bizarre as, like I said in my first post, it only suddenly started happening at the beginning of the month, and the other router's not effected.

Have you tried to adjust the bandwidth over to 20mhz for both bands?? (very strange issue, not sure why it has just popped up and only jumps when the wifi is enabled)

[jhewess]

I'm pretty sure I did try that, yes, but not for very long. I'll switch to 20mhz when I get home and leave it over night and see what happens. I also tried setting the channels to 'auto' to see if the router itself might pick up on any interference etc, but looking at the graph currently, there was a spike about 8am that was massive, so not sure if that's helped.

[jhewess]

OK, I've tested with just the 20mhz setting enabled and its had no effect, the spikes are still there (graph below):
The big spikes at around 6pm was me changing router WiFi settings (amazed it effects ping this much, but there we go), there's a re-sync at 2am (BT maintenance), and wifi spikes at 1am and 9am. There's also a spike just before 11 am, but looking at the logs this might be either the Chromecast or the tablet pulling down an update (no one in the house). I'm also now getting messages in the log re a wl0 reinit, but I assume this is because the 2.4g band is now set to 'auto' channel? However that said, the timer is set at 60mins, but the reinits are happening randomly rather than on the hour.... Log from the last day and a bit attached.

[jhewess]

Also... This is a thread i started over on the Plusnet forums, and it looks like I may not be the only person experiencing wifi ping spikes.. http://community.plus.net/forum/index.p ... 703.0.html

[billion_fan]

Also... This is a thread i started over on the Plusnet forums, and it looks like I may not be the only person experiencing wifi ping spikes.. http://community.plus.net/forum/index.p ... 703.0.html

We are investigating