Am I doing something terribly wrong, or is SpeedFusion bonding useless?

Some background: we use Teradek Bond II for video streaming from remote locations (stationary). It works quite well, and we have been generally happy with it. One thing that we wished it had was the ability to carry non-video data for some low-bandwidth IP-based controls, etc. we would do from laptops or iPads.

So I got an HD4 and FusionHub (25 Mbit license running on AWS). I figured we could have the best of both worlds in something that is super easy to setup on location (we always end up fiddling with Bond II for a bit) and a little light side data on other devices besides video.

In the HD4 I have 4 SIMs (LTE) from 3 different carriers (2 AT&T, 1 Verizon, 1 T-Mobile). All have a latency between 80 and 140 ms.

Without PepVPN/Speeed Fusion, running generates about 40 Mbit down and 10 Mbit up. Looking at the real-time bandwidth monitor, it seems to be using 2 different cell connections for up, and 2 different down.

With SpeedFusion on (WITH Send All Traffic to VPN) that is where things seem to go wacky. It uses all 4 WAN connections, but I get about 12 Mbit down, 6 Mbit up. Have experimented with Outbound Policy set to weighted (equal across the cell) and no outbound policy, and it seems to make no difference.

Are these the expected results? After seeing this I came here and did a search and read a lot of comments about bandwidth going DOWN while bonded. Major bummer.

Am I limited at all by the 25 Mbit throughput license on FusionHub somehow?

Looking for a little guidance.

Thanks for the help!


We have provided the answer here.

Thank you.

That does indeed answer the FusionHub throughput question.

As to the rest of the post though: I guess the bonded connection makes all 4 connections the same speed as the SLOWEST connection? At least that’s what I’ve come to conclude from digging through the forum.

If that is the case, it’s an incredible disappointment, and quite perplexing. Maybe there’s a technical reason for this, but it certainly doesn’t make sense to the end user, and isn’t how other bonding solutions I’ve used work.



Hi Shane, please open a support ticket so we can investigate further:

Ticket 758708 has been open on this for almost a week. A recent speedtest showed 1.2 Mbit down, 4.1 Mbit up with SpeedFusion. Unchecking “send all traffic” to that VPN gets me 35 Mbit down, 13 Mbit Up! I must be doing something very, very wrong.


We are working on the ticket. As we need to perform full performance test to confirm the issue

Thank You

A follow-up for anyone who may be reading this: it seems a resolution was achieved (see below). We are using this in the field in 1 week for a real-world production, so we’ll be able to tell then…but the immediate results are highly encouraging. Apparently a mismatch on MTU between HD4 and FusionHub. Interestingly, I did not change MTU on either device (don’t even see the setting on HD4 web interface, but perhaps it is there). SpeedFusion defaults to 1440, but they changed it to 1428 to solve. Perhaps something to look at if you have SpeedFusion issues with HD4/FusionHub. See ticket resolution from Peplink below:

We have identified the issue and fixed the setting. The SpeedFusion slow performance are due to the MTU miss match between Max HD4 & the FusionHub. I have changed the MTU size for the FusionHub and this should fixed the performance issue.

Initial setting: MTU 1440
Changed: MTU 1428 (Refer to the attached screenshot MTU.PNG)

Can you please redo the speedtest again ?

Base on the PepVPN test tools you should get the below:
MAX HD4 SF Upload speed: 20-27Mbps
MAX HD4 SF Download speed: ~ 50Mbps

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The SpeedFusion slow performance are due to the MTU miss match between Max HD4 & the FusionHub. This is a known issue for the FusionHub version 6.2.2 and targeted will be fix in FusionHub version 6.3.0.

Workaround for this is to define the FusionHub WAN interface MTU size to follow the lowest MTU size that defined for the MAX HD4 cellular WANs

For more information regarding to the FusionHub WAN interface MTU setting, please refer to the attached screenshot.

Thank You

What kind of bonding efficiency where you able to achieve with your HD4? You said you had 4 modems plugged in, did you ever see how much faster the speedfusion made your bond?

Hi TD,

For the support case:

Without SF Bonding:13 Mbps Upload, 35 Download
MAX HD4 SF Bonding: 20-27Mbps Upload, ~ 50Mbps Download (This is limited by FusionHub License).

Cellular WAN speeds/Characteristic are variants from time to time, so you have to take consideration for the available bandwidth before you compare again with the SF bonding performance.

For more information, please refer to the URL below:

Thank You

Just an update to this. We rarely use HD4 at all because it never seems to do much for our throughput. Fired it up today, haven’t changed any settings…it just performs as it does in my first posts. I get faster upload/download WITHOUT going through SpeedFusion than I do with. Pretty frustrating.

Hi Shane,

Just wanted to confirm the setup you mentioned here is same as what you did previously (adjusting the mismatch MTU between HD4 and FusionHub) as your post early this year?

Thanks and regards.

MTU is the same on FusionHub and HD4 cell WANs (I believe 1428). Havne’t changed a thing.

Hi Shane,

This is the same device which reported in RT#758708? If so, please enable Remote Assistance and we will follow from there.

Thank you.

Hi guys,

How did you finally solve the problem? Any follow up?

Thanks a lot,


I would suggest to go through the following URLs to verify the SF performance issue.

Hi - I mistakenly added this along with another reply to a different post. That was not the topic I intended to post to, please accept my apologies for unintentionally “spammin” the forum.

Does this sound similar to what anyone else is seeing?
Looking at
Page 4 describes the use of IMIX (RFC 6985 - IMIX Genome: Specification of Variable Packet Sizes for Additional Testing) traffic flows.
Page 5 describes using IMIX over a multiple WAN speedfusion, with the example Download: 10Mb + 10Mb = 20Mbps – 19% = 16.2Mbps
That sounds excellent.

Our setup with SpeedFusion between two Balance 710s (fw ver 7.1.0) has one B710 with a 500Mbps Internet connection, and the other B710 has 5 WAN Internet circuits:
All WAN Internet circuits have been tested to rated capacity individually.
Download: 100Mbps (W1) +60Mbps (W2)+ 60Mbps (W3) + 60Mbps (W4) + 60Mbps (W5), but the throughput using is 35Mbps.

Does that look right?


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Not immediately no.

  • What speeds do you see over the SpeedFUsion VPN for TCP & UDP tests in the PepVPN test tool?
  • When you run a speedtest what happens to individual WAN latencies?
  • What technology are the WAN links?
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Have you found a solution to your speedfusion problems ? I’m in the same case as you…
Thanks for your feedback