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    Can't break 15mbps OpenVPN throughput

    OpenVPN
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    • C
      coachmark2
      last edited by

      It's been this way since 2.1.4, but I haven't made a thread because it hasn't been a tremendous problem.

      From the OP:

      ISP for Server: Comcast
      Arris CPE in bridge mode
      105mbit/s downstream
      20mbit/s upstream

      ISP for Client1 and Client2: Other business grade ISP
      100mbit/s downstream
      100mbit/s upstream

      Client1 and Client2 are on a network with an ISP that provides 100megabits per second synchronous. They are the only devices on said network.
      The OpenVPN server running on pfSense are on Comcast behind their CPE which is in bridge mode. That connection is rated at 105 down and 20 up, but real world sees 125 down and 22-25 up.

      Whether pushing files TO a server behind the pfSense box or when retrieving files FROM the server behind the pfSense box, speeds never exceed 12-15mbit/s

      I have also used iperf from both sides to test. iperf varies from 11-14mbit/s.

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      • DerelictD
        Derelict LAYER 8 Netgate
        last edited by

        12-15mbit/s

        What do you expect on a 20M upstream?

        Chattanooga, Tennessee, USA
        A comprehensive network diagram is worth 10,000 words and 15 conference calls.
        DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
        Do Not Chat For Help! NO_WAN_EGRESS(TM)

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        • C
          coachmark2
          last edited by

          @derelict

          I understand that pulling files FROM the site would be limited to 20 megabits minus some overhead.

          However, when pushing files the other direction, the speeds are the same. Since my client has 100mbit/s upload and the network behind the pfSense box has 100mbit/s download, I would expect transfers to be higher than 15mbit/s…

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          • DerelictD
            Derelict LAYER 8 Netgate
            last edited by

            Sorry.  I read fast and only saw pulling files FROM server.

            So what are the various CPU loads while you're running these uploads?

            Chattanooga, Tennessee, USA
            A comprehensive network diagram is worth 10,000 words and 15 conference calls.
            DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
            Do Not Chat For Help! NO_WAN_EGRESS(TM)

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            • C
              coachmark2
              last edited by

              :)

              No worries.

              2012R2 VM behind the pfSense box: 3% CPU
              Dell R210 running OpenVPN and pfSense: Average 5-6% with occasional spikes to 9%
              Client: i7-2600k showing 8-10% usage.

              I have also checked carefully here to make sure that nothing is pegging a single thread, etc. Throughput remains in the 15mbit/s range as I'm transferring a .mkv.

              I can add pics if you'd like. :)

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              • C
                coachmark2
                last edited by

                Bump. Any other thoughts? Other tests I could run to see what's happening?

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                • M
                  marvosa
                  last edited by

                  Over the years, I've read many posts on other forums that state using software-based NIC's contribute to that 20 Mb/sec cap.  The posts always mention upgrading to high quality, hardware-based Intel NIC's.

                  Here's an interesting article on network tuning and performance:
                  https://calomel.org/network_performance.html

                  It touches on getting the most out of your firewall by looking at hardware, bus speed, os tweaks, MTU, etc

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                  • C
                    coachmark2
                    last edited by

                    Thanks for the reply but… I'm not using a software NIC.... It's a well-supported Broadcom unit.

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                    • M
                      marvosa
                      last edited by

                      Supported doesn't necessarily = max performance.  What NIC's are you using?

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                      • K
                        kejianshi
                        last edited by

                        Have you considered trying a well supported Intel unit?

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                        • C
                          coachmark2
                          last edited by

                          I don't have an Intel unit to test on. :(

                          But when not using VPN, I can pull 120+mbit/s through that interface all day long. It's just over VPN that it chokes.

                          1 Reply Last reply Reply Quote 0
                          • DerelictD
                            Derelict LAYER 8 Netgate
                            last edited by

                            Wasn't the pfSense store recently selling Dell R210s?  I would think that pretty much clears his hardware.

                            Chattanooga, Tennessee, USA
                            A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                            DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                            Do Not Chat For Help! NO_WAN_EGRESS(TM)

                            1 Reply Last reply Reply Quote 0
                            • C
                              coachmark2
                              last edited by

                              @__Derelict__

                              That was my thought. :( They were actually R200s, but the R210 uses a very similar NIC setup.

                              I have a performance update for inquiring minds. I re-ran my iperf testing with a few different parameters. When I use 8 simultaneous TCP streams, I see at or around 50mbit/s :D That's more like it and very tolerable. UDP looks like about the same.

                              So… what could possibly be limiting a single TCP stream to 15 mbit/s?

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                              • K
                                kejianshi
                                last edited by

                                I also get throttled reliably at certain times of day.

                                Example.  I can always download at my max rate from the web (like hulu or netflix) but a vpn is throttled to death after say 5pm here and not as bad at say 9am.

                                It could be an ISP deal and traffic shaping.

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                                • C
                                  coachmark2
                                  last edited by

                                  Sure, I'm certain that happens to me too. But this IS a VPN. To the ISP, it appears as a bunch of UDP gibberish, so they wouldn't be able to even see the fact that I'm running 1 vs. 8 TCP streams inside the tunnel.

                                  Consistently reproducible is the fact that I get 15mbit/s for a TCP data stream and 50mbit/s aggregate when number of streams >4. No matter the time of the day.

                                  Any idea what could be causing that?

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                                  • K
                                    kejianshi
                                    last edited by

                                    Yeah - sounds like they are throttling you per connection.  That or "long fat pipe" issues.  How far away are these vpns?

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                                    • C
                                      coachmark2
                                      last edited by

                                      Approx. 400 miles by road. Since the East Coast routing tables are all kinds of screwed over right now (thanks Comcast!) it might be going through anywhere from 10 to 17 hops depending on what BGP feels like doing this particular time of day.

                                      How would the ISP realize whether or not I'm pushing multiple TCP connections over this VPN though if it's encrypted UDP?

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                                      • K
                                        kejianshi
                                        last edited by

                                        Are you telling me that all your traffic is going out over this 1 udp vpn but that if you are doing 1 TCP downlaod with this vpn you are limited to 15 but when doing many tcp downloads over this same vpn you can hit 50?

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                                        • C
                                          coachmark2
                                          last edited by

                                          Not exactly.

                                          All traffic going over this VPN. I have 100mbit/s UPLOAD speed for my client. I have 100mbit/s download speed where the OpenVPN server is. Pushing FROM my client TO my server, I would expect 100mbit/s minus some overhead. I instead get 15mbit/s with one TCP stream or 50mbit/s with 8 TCP streams.

                                          50 is acceptable, and looks like ISP shaping. 15 is not good or expected.

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                                          • K
                                            kejianshi
                                            last edited by

                                            You didn't answer my essential question.

                                            Are the TCP stream all inside the vpn when you test or are you testing without vpn?

                                            If you are getting these results while everything is being tunneled on vpn, then your problem is latency.  Latency will cause 1 single TCP stream to have limited available bandwidth.

                                            This is the "long fat pipe" issue I mentioned earlier.  The cure for this is to either break a single file into multiple tcp streams for transfere or to transfer many files at once to max out available bandwidth.

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