VPN question...

[Sushiglobster]

I recently signed up for an OpenVPN service.

When running the provided OpenVPN software and logging into the VPN via the software my connection speeds are very high and stay around 24/3 which is what I am paying for with ATT Uverse.

When I set my RT-N66U (latest Merlin firmware) to connect to the VPN my speeds drop down dramatically to roughly 4/3 or so.

Why is this happening? Is it a setting of some sort? I can understand why the software allows for my connection speeds to stay normal but when having my router do the tunneling, my connection speeds drop to awful levels.

Help!

 

[RMerlin]

Hard to give you an actual answer not knowing the actual speed you are talking of. Keep in mind that the 600 MHz CPU of your router might not be able to do the encryption AND routing at full speed compared to a multi-gigahertz PC if you are talking fairly high speeds.

 

[CaptainSTX]

Off Loading VPN Processing

To minimize the speed loss when running a VPN connection you may need to off load the processing.

Take a look at Sabai Technology's web site. They make a VPN accelerator to work in conjunction with certain routers to handle the VPN processing and increase throughput.

Read the testimonials, FAQ, etc. on their web site to see if their technology might resolve your issues.

I know it works well for me.

 

[Sushiglobster]

Hard to give you an actual answer not knowing the actual speed you are talking of. Keep in mind that the 600 MHz CPU of your router might not be able to do the encryption AND routing at full speed compared to a multi-gigahertz PC if you are talking fairly high speeds.

This makes complete sense to me now. It was also something that was mentioned to me by my VPNs tech support as well. It would completely account for why the software connection is much faster given my PC is much more beefier than the router, especially since we are talking OpenVPN. As for speeds, my UVERSE connection speed is 24Mb down and 3Mb up. My speeds when connected through the router drop to 4Mb down and 3Mb up. HOWEVER, I did switch over to a different node which had less hops and acceptable ping rates. I now sit around 8-12Mb down.

I also need to mess around with MTU rates. I've read that adjusting MTUs between 1400-1500 may help with an increase.

However, I still imagine that it's hardware that's keeping things slow.

Maybe we can find a way to overclock that 600Mhz cpu on the RT-N66U

 

[Sushiglobster]

To minimize the speed loss when running a VPN connection you may need to off load the processing.

Take a look at Sabai Technology's web site. They make a VPN accelerator to work in conjunction with certain routers to handle the VPN processing and increase throughput.

Read the testimonials, FAQ, etc. on their web site to see if their technology might resolve your issues.

I know it works well for me.

Thanks for the suggestion. I did not know such a thing existed. I read through the product information, but it seems to only support Linksys E2000, E3000, E4200 and Asus N-16 products. No RT-N66U support Not to mention it's a bit more than the cost of my the actual RT-N66U.

 

[RMerlin]

This makes complete sense to me now. It was also something that was mentioned to me by my VPNs tech support as well. It would completely account for why the software connection is much faster given my PC is much more beefier than the router, especially since we are talking OpenVPN. As for speeds, my UVERSE connection speed is 24Mb down and 3Mb up. My speeds when connected through the router drop to 4Mb down and 3Mb up. HOWEVER, I did switch over to a different node which had less hops and acceptable ping rates. I now sit around 8-12Mb down.

I also need to mess around with MTU rates. I've read that adjusting MTUs between 1400-1500 may help with an increase.

However, I still imagine that it's hardware that's keeping things slow.

Maybe we can find a way to overclock that 600Mhz cpu on the RT-N66U

If you can select the encryption type, make sure you use one that starts with AES. With recent Asuswrt-Merlin I replaced the AES encrypt/decrypt code with highly optimized ASM code taken from newer versions of OpenSSL, which gives a pretty nice boost in performance when dealing with AES and SHA encryption types.

Also take a look at the CPU load while doing a large transfer to see if your CPU is actually capped (load average should be close or above 1.0 in that case). You can check it through the Tools -> Sysinfo page.

 

[Sushiglobster]

If you can select the encryption type, make sure you use one that starts with AES. With recent Asuswrt-Merlin I replaced the AES encrypt/decrypt code with highly optimized ASM code taken from newer versions of OpenSSL, which gives a pretty nice boost in performance when dealing with AES and SHA encryption types.

Also take a look at the CPU load while doing a large transfer to see if your CPU is actually capped (load average should be close or above 1.0 in that case). You can check it through the Tools -> Sysinfo page.

Thanks RMerlin! I appreciate your help and suggestions. I'll check it out.

 

[Sushiglobster]

Also take a look at the CPU load while doing a large transfer to see if your CPU is actually capped (load average should be close or above 1.0 in that case). You can check it through the Tools -> Sysinfo page.

Okay, so I ran some speedtests over at speedtest.net and had another window open so I can monitor the CPU load as you mentioned.

I'm not sure what I'm looking at exactly, but these numbers popped up during test: 0.08, 0.02, 0.00

It doesn't seem high, however a 1080P YouTube video gives me this result: 0.99, 0.29, 0.10

That seems high. It does fluxuate quite a bit, 0.99 eventually dropped to .49 or so..then back up to .75...none the less, it seems like it remains high.

This would be evidence of a high CPU load with OpenVPN yes?

EDIT: 1080P YouTube video just showed this on CPU load: 1.14, 0.55, 0.21

EDIT: Downloaded a 176MB Nvidia driver, CPU maxed out around here: 0.77, 0.56, 0.28

 

[RMerlin]

1.00 means that one process is using 100% of the CPU. So anything close to that on the first number would mean the router is fully using the CPU.

The first number is the current average. The second number is the average over 5 mins. Third number is average over 15 mins.

 

[CaptainSTX]

Thanks for the suggestion. I did not know such a thing existed. I read through the product information, but it seems to only support Linksys E2000, E3000, E4200 and Asus N-16 products. No RT-N66U support Not to mention it's a bit more than the cost of my the actual RT-N66U.

Yes it is expensive.

You would probably use your RT-N66U as your primary router then the Sabai router and VPN Accelerator as an AP of the primary router.

This is how I have my network set up. Primary router connects direct to ISP and services G only wireless clients. E3000 with Sabai's dual gateway software and Accelrator handle N clients and VPN connections for both Wifi and Ethernet connected devices.

If you read the testimonials people b uy this technology need the throughput to stream video from USA to Europe or Asia.

Hopefully tweaks to your router bring your speed up to what you need for your applications. With my setup from Sabai i get twice the speed that I was getting running a PPTP VPN on a router flashed with DD-WRT.

Otherwise you may have to pay to play.

 

[Sushiglobster]

Hey RMerlin,

My VPN service is adding PPTP to their line up of services. As I understand it, PPTP is less secure but also less taxing compared to OpenVPN so maybe performance may improve compared to using OpenVPN. How would I go about getting Merlin firmware to use PPTP if I wanted to set this up on the RT-N66U? I see sections for OpenVPN, but no PPTP.

Any insight?

 

[RMerlin]

Asuswrt only supports PPTPD as a server, not as a client.

 

[Sushiglobster]

Oh man, bummer.

 

[Sushiglobster]

So when the router's CPU is under heavy load, is it normal behavior to dramatically reduce internet connection speeds? Is this because it's throttling?

Would putting my Uverse Mode/Gateway into a passthrough/bridge mode help out with OpenVPN speeds or is the CPU's load to blame for the low speeds?