Speed Fusion bonding a 8/0.7 connection and a 9/6 connection .. creating a 17/6.7 connection?

Hi, Pretty new to Peplink and bonding multiple connections.

I currently have one connection at 8mbps download and 0.7 upload and a second at 9mbps download and 6 upload.

i have created a speed fusion connection to another site and that is set up correct. However when i have bonded the two connections i am getting speed tests of around 8.8 mbps and 3.6 upload?

Is there a setting that i have missed or needs to be changed to increase the download as the upload seems to be increasing but the download seems to stay similar or is it not possible to do?

any help or ideas would be appreciated.



To get an optimum bonding throughput, you need 3 prerequisites condition below:-


  • Latency must less than 1000ms for each WAN link.
  • The different of latency between WAN links must lower than 150ms.


  • The bandwidth of the slowest link is at least 15% of the bandwidth of the fastest link.

Look like the upload bandwidth between 2 links doesn’t meet the requirement above. SpeedFusion Hot Failover is recommended for your environment. If you need our further checking, please open ticket for us to take a closer look.

Thank you.

Apologies to @corner26 for hijacking your thread with a question of my own, but I am in much the same situation as you, with no prior experience of Peplink’s SpeedFusion bonding.

The information provided here by TK is all new to me, and I didn’t notice any of these prerequisites being made clear in the marketing information. They may be obvious to some, but certainly weren’t to me, and I imagine others may find themselves in the same boat!

TK - Can you please confirm whether, assuming the above criteria are met, it is possible to set up SpeedFusion bonding if one party only has 1 WAN link, and the other has multiple WAN links?

To use my own situation as an example:

Balance A
5 x WAN links, with total throughput of 65/5 Mbps

Balance B
1 x WAN link, with throughput of 13/1 Mbps

  • Each WAN link has latency of 250ms - 350ms
  • Difference in latency is <150ms
  • 13 Mbps is 20% of 65 Mbps
  • 1 Mbps is 20% of 5 Mbps

Or does Balance B need to have 2 WAN links in order for Balance A to enjoy SpeedFusion bonding?

I hope this question may help others, too!

Many thanks, Edward

Hi Edward,

Yes, you can use SpeedFusion to bond 5 WANs for Site A together with 1 WAN for Site B.

Do note that the performance between Site A & Site B as below:

Site A – Upload –> Site B ( ~ 5Mbps - Overhead )
Site A <– Download – Site B ( ~ 1 Mbps - Overhead )


Site B – Upload –> Site A ( ~ 1 Mbps - Overhead )
Site B <– Download – Site A ( ~ 5Mbps - Overhead )

Thank You

Hi sitloongs

Many thanks for your reply. I’m delighted to hear that SpeedFusion will work if one side has just one WAN (although it’s easy to get another if necessary)

Just to confirm, are you saying that when connecting to the internet, from Site A’s total available 65/5 Mbps throughput, the overhead will be 5Mbps on upload? That means there is none!

Similarly, from Site B’s 13/1 Mbps, the upload speed will be zero due to overhead of 1 Mbps?

Please note that I am not concerned about uploading / downloading between Sites A and B. I have bought the two Balances purely to get the bonding and for both sides to enjoy faster internet connections overall.

When I use a VPN service such as VyprVPN, I note a performance drop of about 20% when testing on SpeedTest.net. I can understand why SpeedFusion would impact similarly, but to lose all uploading ability is going to be a problem.

Can you please verify?

Thanks again, Edward

Hi Edward,

Let me rephrase the expected performance for the SpeedFusion:

Local connections:
Site A – Upload –> Site B ( ~ 5Mbps - 20 % Overhead = Expected 4Mbps )
Site A <– Download – Site B ( ~ 1 Mbps - 20% Overhead = Expected 0.8Mbps )


Site B – Upload –> Site A ( ~ 1 Mbps - 20% Overhead = Expected 0.8Mbps )
Site B <– Download – Site A ( ~ 5Mbps - 20 % Overhead = Expected 4Mbps )

Internet Connection for Site B –> Site A –> Internet
Expected Download: 4Mbps
Expected Upload: 0.8 Mbps

Please refer to the attached illusion for the connections. The bottleneck still at the Site B whereby the upload Speed & download are limited to the available bandwidth between Site A <–> Site B.

Thank You

Hi sitloongs

Thank you very much for your detailed message, and for going to the trouble of doing an illustration. Really very kind of you.

Am I right in understanding that the bottleneck you describe only applies to uploading / downloading done between Sites A and B?

If Site A has a 65/5 Mbps connection, at roughly what speed will it be possible to download from iTunes, for example? What kind of upstream bandwidth will be available to Site A when using Skype / FaceTime / Fuze HD to the world at large? (i.e. Not VOIP between the two sites)

Thanks, Edward

No problem for asking a question Edward.

The set up i currently am using is two line at site B which both have download of around 7-8 Mbps and upload of around 0.7Mbps, i currently have these lines bonded through share band and my speed test results are around 14/1.35 which is pretty much the combined speeds from both lines.

The above figures were using one of those lines and a 4g Device but to make it easier and the download and upload speed to be practically the same we will use both the standard lines. 8/0.7 + 8/0.7

Rather than using share band i am trying to get the same figures by using speed fusion and bonding the two lines together on the a peplink 310.

Site B has a speed fusion connection with Site A (peplink 380) however when i do bond these two lines together (similar to my original question) I get speeds of around 8-9/1.2-4 so to me looks as if the uploads are bonding but not the downloads? My logic would suggest i could get the same speed as i was getting with the share band bonding with the peplink bonding?

Thank You

Sorry this may be a repeat of what was just discussed on this thread but to clarify, if I have a connection of 10/3 at site a (vpn server) and the site B I am bonding two lines. Is the max download and upload I can get from the bonded lines the same as the output from site A?

Essential site A 10/3
Site B two lines of 8/0.7

The max I could get would be 10/1.4?

@corner26, you are on the correct path here. Your bonded download speed is always going to depend on the upload speed of the other site. In your case site A only has 3Mbps upload capacity so this will be your maximum download speed at site B.

Your bonded connection at site B would be 3/1.4

@Tim S. Thank you for your reply that has cleared some things up.

Does the download at site A effect anything to do with the speed from site B or is it just the upload on site A?

It goes both ways. Your download speed at site A is 10Mbps but your max upload speed coming from site B is only 1.4Mbps, so the max download speed at site A would be 1.4Mbps.

Keep in mind that this is only for the traffic that actually goes through the tunnel. The default SpeedFusion behavior is split tunnel, meaning only traffic that is destined for a remote subnet actually goes across the tunnel and regular browsing to the internet will go directly out the WAN connection to come back at full speed. This works out great for most customers but for some applications people do choose to force ALL traffic over the tunnel.

Hi Edward,

Clients –> Site B <– 4Mbps/0.8 (Bonded Speeds) –> Site A <– 65Mbps/5Mbps –> Internet

The application speed will follow bonded Speed between Site A & Site B (4Mbps/0.8Mbps).

Thank You

@Tim.S my main goal is to basically get better speeds at site B by bonding 2 or 3 lines together. Currently on my setup the outbound policy has the VPN as Priority number one pushing all traffic through the VPN purely for the reason to improve the speeds from have a standard connection a site B to 2/3 lines bonded.

Would you suggest that’s the wrong way to do it or is there any other ways using the peplink devices to achieve this. The other option would be to increase the connection at site A to allow higher speeds from site B?


Since you will send all traffics from site B to A, upload bandwidth at site A will be important. Suggest to upgrade the WAN link on site A.

Hi sitloongs

Thank you! That clears things up perfectly!

Is there a “How SpeedFusion works in the real world” PDF that I’ve missed? I’m sure it would be useful for all your customers who don’t have a background in networking and computers / IT in general. Diagrams and all! :slight_smile:

Thanks again, Edward

Hi Edward,

Please refer to Peplink DesginLab for the info.

The Design Lab include the collection of network designs using Peplink technology & detailed diagrams from real-world deployments.

Design Lab

Thank You

Hi sitloongs,

Thank you very much, but I still don’t see where it’s explained that SpeedFusion can eat up 20-25% of one’s available bandwidth in overhead, or that data can only be transferred between bonded sites at the rate of the slowest connection…

Please don’t misunderstand me. I think Peplink is wonderful, but I don’t believe one gets the full picture from reading your marketing material, and I would imagine this leads to an unmatched expectation at times.

Best wishes,


Hi Edward,

Believe that you are looking at the best Practice guide for SpeedFusion:

Here are the download Link:

Thank You
Sit Loong

Thank yiu, Sit Loong! Very helpful!

However, i do think it would be extremely useful to have clear a link to this (and any other relevant information) on the SpeedFusion web pages, so that prospective customers get a better understanding of the technology, beyond “unbreakable, encrypted bonded connections”

With thanks and best wishes,