Abysmally slow UDP upload speeds, but only over wireless?

[neomech]

I posted this issue in a discussion about the new AC86U (which rocks) but thought I’d post to the general vpn group, as I’m not sure my issue is device specific.

My problem relates to using UDP as my OpenVPN protocol. When I do, I get fantastic download speeds (close to what I get without a VPN) for both wired and wireless devices. I also get good upload speed, but only for wired devices. Wireless devices have terrible scores (frequently choking down to 0) uploading with the UDP protocol.

If I switch to TCP my wireless upload speeds are just fine. Within 10% of my wired speeds and several times faster than UDP. But unfortunately my wireless download speeds get cut almost in half moving to TCP.

Again, UDP uploads just great over a wired connection, and also works great downloading over wireless. And in both wired and wireless, UDP download is twice as fast as TCP download (which is why I’d like to stick with UDP if I can).

Here are the results I'm getting (download/upload Mbps):

No VPN (both wired and wireless): 125/10.5
VPN with UDP - wired: 120/10.0
VPN with UDP - wireless: 120/1.5
VPN with TCP - wired: 75/9.5
VPN with TCP - wireless: 65/9.5

So since I want to keep my very fast UDP download speeds, is there a setting I can change to make UDP upload speeds work well over wireless? I assume from some reading that I am experiencing packet loss issues. Is this one of those times to use an sndbuf or rcvbuf setting? Of course I’m probably way off base.

What's really surprising (for me, anyway), is that I didn't think the wireless communication between the device and the router had really anything to do with the VPN...it's just sending information between the wireless devices and router over the usual wifi network. It's the router that's doing the whole VPN encryption/communication thing with the ISP. I'm confused why the wifi transmission between the device and the router wouldhave any real impact on what's happening between the router and the ISP.

For what it's worth, there is no noticeable difference in CPU load, whether I am using wired or wireless, UDP or TCP. Upload actually seems to use hardly any CPU at all.


Any advice is greatly appreciated!

 

[JJQuin]

I just installed the official 382.2_beta3 on my RT-AC86U and found the same issue. My download speeds are within 3-5mbps of my max but my upload speed drops to 10% of my max. Strange thing is it only happens on PIA VPN. Works fine on NordVPN. Of course, I was in the process of switching to PIA!

Speed tests (Note my wired speed is using Powerline adapters max speed is 75mbps)
PIA - 114/1.5 - Wireless
PIA - 72/11 - Wired
NordVPN - 72/11 - Wired
NordVPN - 112/11 - Wireless
PIA client on my Windows PC instead of on the AC86U - 114/11 - Wireless & 72/11 Wired.

I tried turning off QoS, no luck. Also tested PIA on both aes-256 and aes-128. Even setup PIA on both client 1 and 4 to make sure it wasn't the core it was using (NordVPN is on client 2).

My next test is going back to 382.1_2. It's just such a pain to downgrade the firmware.

Has anyone else seen this issue?

 

[JJQuin]

I set a ticket to PIA. They got back to me in about 15 minutes! They sent me a new custom configuration that worked great. The PIA Chicago server for some reason was doing 20mbps download with the new config but the midwest and east servers were perfect. 114/11!

Here's the config they sent me:

explicit-exit-notify 2
ifconfig-nowarn
tls-client
persist-key
persist-remote-ip
remote-cert-tls server
auth-nocache
fast-io
sndbuf 524288
rcvbuf 524288

I actually tried these using the 1197 port/aes-256 configuration. It worked and used the higher encryption but gave me some conflicting setting warnings in the log.