Openvpn upload speed limited to 355kb/s


I am using openwrt on my router for a couple of years, but I have the following problem when using OpenVPN.

Scenario: When connecting using the openvpn client to my router from another location everything is working fine. When I want to copy something from a server behind the router with openwrt the speed of the upload is limited to 355kb/s. If I upload something to the server then the speed goes to 2Mb/s.
The internet speed when running speedtest is ~90MB/s upload/download.

So I believe that there is a setting that I need to modify at the level of the interface to allow to increase the speed of the upload.
I have checked the load of router and it isn't that high to not allow higher speed. The server is connected to the router via a 1GB connection.

Router model: TP-Link TL-WR1043ND v2.x

Can you suggest on what I can do to increase the speed of the upload ?

Thank you

This router is rather old. Verify with top or htop that CPU during the transfer is not over utilized.

1 Like

I already verified and the CPU doesn't go above 10%. It also has enough RAM available.
I have already search the forum and I haven't found any answer or anybody with the same problem.

Version running is 19.07.5 on the router.

Can you check cables? Because i've seen similar issues in past.

Already tested this.

If I am in the network with my laptop transfer between the laptop and the server is around 10mb/s.

Download speeds and upload speeds to the internet from the server is also consistent with 10mb/s.

So for this reason I have excluded the cables.
What I find strage is that the speed is 355kb/s when uploading data from the server, but 2mb/s when downloading data through the same vpn.

I am thinking that it might be an issue with the TAP adapter that I am using, but I am unsure at the moment as I have been able to find any limitation concerning this.