Speed issues with ASUS RT-AC87U

[bleedr 3]

Hello,

I've tested some of the servers which are pretty near to me, even in the same city and I got no speed faster than 10-20 MBit/s.

I tried it as OpenVPN on my router which should be able to use VPN up to my speed of 50 MBit/s. I used the configuration which is provided for the ASUS RT-AC87U.

So I tried disabling it on my router an using the Application for Mac OS X, I was surprised using the same server I got 50 MBit/s!

Can you please help me, what is wrong with the router and why doesn't it provide the speed? The CPU should be able to handle it - it has two cores and not even one goes up!

 

[Staff 9751]

Hello,

 

just an idea: please check the OpenVPN socket buffers sizes in the router (you can see how they are set for example in the OpenVPN logs). When you run the client, it tells OpenVPN to set buffers of 128 kB. Buffers smaller than 64 kB may slow down performance significantly when required throughput exceeds 20 Mbit/s.

 

The directives for OpenVPN are (respectively for the send and the receive buffer):

sndbuf n

rcvbuf n

 

where n is in bytes (so set them to 131072 to have 128 kB buffers).

 

Kind regards

[bleedr 3]

Thanks for the fast reply,

I checked the logs and so far I can see it does set the buffers correct:

 

Oct 13 02:51:45 openvpn[9721]: Socket Buffers: R=[122880->131072] S=[122880->131072]

 

Any other idea?

[dj77 6]

Which Firmware you use?

[bleedr 3]

I tried the newest official from ASUS and the newest from Merlin.

Both had the same results.

[go558a83nk 352]

I use an Asus AC68 with merlin firmware as VPN client and I've never had your experience.  If it's slow or throttled it is with either the router or Eddie.

 

one thing to look at on the router is the status page with the CPU usage graph.  make sure that both cores are being used when you're downloading something and openvpn is having to work hard.  what that shows is that kernel work is done on one core while openvpn is running on the other core.

 

if only one core is being used then try switching to another openvpn client in the web GUI as programming sometimes has different clients mapped to different cores.  or you can just change core affinity using taskset via an SSH session.

[dj77 6]

Can you maybe Try Google DNS or Open DNS?

[go558a83nk 352]

Can you maybe Try Google DNS or Open DNS?

 

DNS has nothing to do with download speed capability.  Remember, all DNS does is convert "www.youtube.com" to IP address.

[bleedr 3]

 

I use an Asus AC68 with merlin firmware as VPN client and I've never had your experience.  If it's slow or throttled it is with either the router or Eddie.

 

one thing to look at on the router is the status page with the CPU usage graph.  make sure that both cores are being used when you're downloading something and openvpn is having to work hard.  what that shows is that kernel work is done on one core while openvpn is running on the other core.

 

if only one core is being used then try switching to another openvpn client in the web GUI as programming sometimes has different clients mapped to different cores.  or you can just change core affinity using taskset via an SSH session.

 

You are right, it uses only one CPU instead of two!!!

What do you mean with OpenVPN client switching? There is only one in the router? 

 

Can you provide me with more info about taskset?

 

I hope you don't mean PPTP or L2TP as I don't want to use these protocols for security reasons!

[go558a83nk 352]

 

I use an Asus AC68 with merlin firmware as VPN client and I've never had your experience.  If it's slow or throttled it is with either the router or Eddie.

 

one thing to look at on the router is the status page with the CPU usage graph.  make sure that both cores are being used when you're downloading something and openvpn is having to work hard.  what that shows is that kernel work is done on one core while openvpn is running on the other core.

 

if only one core is being used then try switching to another openvpn client in the web GUI as programming sometimes has different clients mapped to different cores.  or you can just change core affinity using taskset via an SSH session.

 

You are right, it uses only one CPU instead of two!!!

What do you mean with OpenVPN client switching? There is only one in the router? 

 

Can you provide me with more info about taskset?

 

I hope you don't mean PPTP or L2TP as I don't want to use these protocols for security reasons!

 

no, I do not mean PPTP or L2TP. 

 

not sure what the stock firmware looks like but firmware 378.55 Merlin firmware has two openvpn clients.  just select which client you use in the GUI.

 

you can search the web for how to use taskset.

[bleedr 3]

I installed Asuswrt Merlin, the newest beta. Now it works with both CPUs.

I've still not a stable speed, but it's a lot better.

 

 

 

Can you maybe Try Google DNS or Open DNS?

 

DNS has nothing to do with download speed capability.  Remember, all DNS does is convert "www.youtube.com" to IP address.

 

 

I've open DNS as a second option (after 10.4.0.1). The speed drops with Usenet connections, it might really be that resolving the address makes the speed drop temporary, or?