Internet speed reduces significantly when using openconnect/anyconnect on the openWrt

Hello everyone, I live in a dormitory where to use the internet I must connect to my university network through anyconnect/openconnect. When I use openconnect VPN on a device, for example, my phone or PC, I get an internet speed of around 70 Mbps. But when I installed the anyconnect on the Luci I have been able to use the internet but the speed was significantly reduced to 12 Mbps. I want to use anyconnect on the router rather than the device itself because I have some devices, for example, Alexa, a printer, a smart bulb, and Xbox, they cannot connect to the internet since it is not possible to install anyconnect on them.
My question is why the internet connection slows down too much when using openconnect on the router and is there any way I can fix this issue? I am not really very well versed in OpenWrt. I use openWrt onTP link Archer C7 router. Any suggestion is appreciated.

Because CPUs are used to encrypt the traffic.

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Does that mean, without having a more powerful router it is not possible to get the same speed as I usually get?

  • Using a VPN takes CPUs, so no; but
  • Some devices have a crypto accelerator/processor, so using a VPN with a compatible encryption algorithm on such devices could help
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OpenConnect is based on SSL, which is not very fast on a small CPU.

As far as what could be done without buying anything, you could try setting up your PC to share its Internet connection (after it passes through VPN) or run OpenWrt in a VM.


In both cases I guess, I will have to keep my PC running to share internet. Which wouldn't work for me.

That gels with the Archer C7's QCA9558 CPU and from what I'm gathering about Openconnect is an AES-256 encrypted VPN, the CPU just cannot do more than that. To get higher speeds, or even your full line speed, you would need a much more powerful router, simple (if understandably disappointing for you) as that.


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