Slow OpenVPN on AC87r

[jazzy_jeff_81]

I have an AC87R router with the latest build and I have a subscription to PIA for OpenVPN. I am using the connection via my router, but I am achieving speed of 2-3Mbps, sometimes less than a 1MB! My cable internet providers offers me 60Mbps down and 4Mbps up, which I achieve when using the speedtest site.

Does anyone else have this issue? The AC87R is supposed to be one of the best routers out there, and I've read that speed of 50Mbps can be achievable. I am using the UDP protocol, and changing it TCP doesn't make any difference.

Any ideas what's wrong and what is causing this slow speed?

Thanks.

 

[cosmoxl]

I'm sure you've tried different servers? A few months ago somebody bought an AC87 for use with PIA and shared his happy experience on the PIA forums. He was getting over 50mbit/s down IIRC.

It could be nothing to do with you, and nothing to do with PIA, but your ISP that's throttling openvpn.

 

[sfx2000]

Have you tried the OpenVPN client on your desktop?

Those little ARM cores in the router are working hard enough, and OpenVPN just beats them to death..

 

[jazzy_jeff_81]

I tried the 2 UK server options that I am presented with, but both offer the same speeds. I tried a US server too, and this also offers no speed increase. Yes perhaps my ISP is throttling the connection. I never contemplated this possibility.

I haven't tried the openvpn client on my desktop, because I assumed my asus router could handle it. I checked the CPU stats on the router, and to be honest my cpu doesn't seem to be working that hard and memory is less than 50% utilization.

Are there any other users of PIA in the US that have Charter broadband and have speed issues with OpenVPN?

I'll try on the desktop and then I'll try it at my parents house in the UK to see if the problem persists on their ISP.

 

[john9527]

Not Charter, but I use PIA in the US and get over 50Mbps on my overclocked AC68R. Here's a post with my setup and some speedtest results (I was surprised I was able to get near 50Mbps even going to a server in Germany).
http://www.snbforums.com/threads/openvpn-on-rt-ac68u.23548/#post-174596

 

[golgi42]

Pulling 50 up and down (max of my regular FiOS connection) with Merlin's latest firmware through PIA on a RT-AC68P. This is when connecting to servers from the US to Europe. Nothing special in my settings it all, just the default. It is very impressive. So it could be a Charter issue. Before I was on Comcast, and couldn't even get close to the same speeds.

 

[Chrysalis]

I get a paltry 6mbit on my openvpn, the server and router are both nowhere near cpu saturation so I always put it down to a openvpn protocol limitation.

 

[RMerlin]

I get a paltry 6mbit on my openvpn, the server and router are both nowhere near cpu saturation so I always put it down to a openvpn protocol limitation.

Most common reason for performance issues (after the CPU power and the remote server have been ruled out) is an mss/mtu mismatch. Search the forums on this, I believe there are a few discussions about how to optimize an OpenVPN tunnel's MSS.

 

[jazzy_jeff_81]

Thank you everyone for your responses.
Merlin, adding these settings to the custom config page in the openvpn page allowed me to get 12.5Mbps speed. A significant improvement!
tun-mtu 1500
mssfix 1400

I'll play with these settings some more and try and get some more Bandwidth! Thank you All!

 

[Chrysalis]

Most common reason for performance issues (after the CPU power and the remote server have been ruled out) is an mss/mtu mismatch. Search the forums on this, I believe there are a few discussions about how to optimize an OpenVPN tunnel's MSS.

yeah I already done loads of playing with those values and the max throughput doesnt budge, I suspect I have an RWIN problem and its failing to grow past a small size, but luckily it isnt a big issue as 6mbit is enough for the purpose I use the VPN for.

 

[Skirk]

yeah I already done loads of playing with those values and the max throughput doesnt budge, I suspect I have an RWIN problem and its failing to grow past a small size, but luckily it isnt a big issue as 6mbit is enough for the purpose I use the VPN for.

I have this issue too. It would appear in my case that the adaptive QoS is the issue. When the VPN client is enabled my download speeds are limited to the cap set for upload speed in the QoS settings. If the QoS is turned off I get full speed. Additionally if the VPN client is off and QoS is on I get full speed. And yes, I haven't got the fields filled in back to front Furthermore, while performing a speedtest with the VPN and QoS turned on, the Adaptive QoS - WAN/LAN Bandwidth Monitor registers the download test in the Upload monitor and vice versa. Hope that makes sense.

Has anyone else noticed this?

Edit: The result is the same for clients using VPN via "Policy rules" or "All traffic"

 

[regular]

I have this issue too. It would appear in my case that the adaptive QoS is the issue. When the VPN client is enabled my download speeds are limited to the cap set for upload speed in the QoS settings. If the QoS is turned off I get full speed. Additionally if the VPN client is off and QoS is on I get full speed. And yes, I haven't got the fields filled in back to front Furthermore, while performing a speedtest with the VPN and QoS turned on, the Adaptive QoS - WAN/LAN Bandwidth Monitor registers the download test in the Upload monitor and vice versa. Hope that makes sense.

Has anyone else noticed this?

Edit: The result is the same for clients using VPN via "Policy rules" or "All traffic"

I have the exact same problem but no response to raising this issue on the main firmware thread. Hopefully it can be remedied!

 

[Skirk]

I have the exact same problem but no response to raising this issue on the main firmware thread. Hopefully it can be remedied!

Just spotted your post, I missed it on my initial search before posting here I'm afraid. I thought the op's VPN speeds appeared similar to their cable provider's upload speed which is why I thought we may have had the same problem (and not to hijack the thread)

I have been using the Astrill app without issues, but this weekend I tried PIA with selctive routing which is when the problem became apparent - ADSL2 upload limits are quite restrictive! If this appears to be an isloated problem I'll try a factory reset and manually re-enter settings....doh!

 

[Skirk]

Okay, I have just performed a factory reset and entered all settings manually.

The issue has persisted; the VPN client breaks the adaptive QoS or vice versa. The VPN download speeds are limited to the upload speed set in the QoS. Apart from @regular can anyone else reproduce this?

Thanks.

 

[cosmoxl]

so maybe there is a bug with openvpn and QoS interacting. but, is there a reason you have to use QoS? why not just shut it all off? less work for the router to do.

 

[jazzy_jeff_81]

I spoke too soon on my mtu settings adjustment. I went back down to 3-4Mbps connection speeds on the VPN. I also had QOS enabled and turned it off. This improved my connection speed to 5.5Mbps, but that isn't a significant increase and I can't confirm that it will stay like that, because my initial change on the mtu settings boosted my connection to 12Mbps.

 

[Skirk]

so maybe there is a bug with openvpn and QoS interacting. but, is there a reason you have to use QoS? why not just shut it all off? less work for the router to do.

I have turned off QoS in the meantime. Unfortunately on an ADSL connection QoS is somewhat necessary in our home, and those speeds don't seem to stress the router much with both the VPN client and QoS enabled

 

[rlcronin]

I've got a related question that seems appropriate in the context of this discussion (but will move it to a new thread to avoid topic drift if you all think that would be better). If I were buying a new Asus router and VPN performance was a key requirement, which model would be best? I was contemplating getting an AC68U (mostly because I really like the vertical form factor and don't need the bells and whistles of the newer models with their silly looking forest of antennas and such).
--
bc

 

[RMerlin]

I've got a related question that seems appropriate in the context of this discussion (but will move it to a new thread to avoid topic drift if you all think that would be better). If I were buying a new Asus router and VPN performance was a key requirement, which model would be best? I was contemplating getting an AC68U (mostly because I really like the vertical form factor and don't need the bells and whistles of the newer models with their silly looking forest of antennas and such).
--
bc

The RT-AC68U with its 800 MHz dual core CPU should give you around 60 Mbps of OpenVPN throughput (I was doing some development work this weekend on it, so I happen to have some very fresh iperf benchmarks results for it), which should be enough for most. If you do need an extra oomph, the RT-AC87U has a 1 GHz CPU.

 

[rlcronin]

The RT-AC68U with its 800 MHz dual core CPU should give you around 60 Mbps of OpenVPN throughput (I was doing some development work this weekend on it, so I happen to have some very fresh iperf benchmarks results for it), which should be enough for most. If you do need an extra oomph, the RT-AC87U has a 1 GHz CPU.

60 Mbps sounds more than adequate for my purposes, many thanks for the information Merlin.
--
bc