Difference in Speed
One question that often comes up when evaluating SpeedFusion bonding performance is that
Speedtest.net says that I have 10Mbps on this landline/4G LTE, but SpeedFusion says it is only 5Mbps?
There are a couple of dimensions to this puzzle.
First of all SpeedFusion is a point-to-point virtual private network (VPN) protocol. Like every other VPN protocol e.g. IPsec and L2TP etc., SpeedFusion does encapsulation on your network traffic for routing purposes. This is similar to how courier adds labelling to your parcel for shipping.
This extra layer of encapsulation costs 10 to 20% of bandwidth. In return, it provides all the sweetness and benefits of a VPN and, uniquely to SpeedFusion, bandwidth bonding.
VPN connects two remote networks as if they were one e.g. connecting a remote branch to the headquarter and allow it to access resources hosted at the headquarter. Bandwidth bonding allows you to use multiple internet connections of different underlying technologies at the same time for extra bandwidth and resiliency.
The second dimension is that
It is a completely different road going from where you are to speedtest.net and where you are to your Peplink router at the other end of the SpeedFusion connection.
For starter, speedtest.net and other speed test services automatically gear you to a server nearest you for the speed test. The bandwidth you have to this server, as you can imagine, may not truly reflect the bandwidth you have for day-to-day web browsing, emailing or audio/video conferencing activities where your traffic may need to go to a different continent.
For SpeedFusion, the traffic is going from where you are to the Peplink router at the other end of the SpeedFusion connection. There your Peplink router is using one or multiple internet services from different internet service providers. The route between you and your Peplink router at the other end of the SpeedFusion connection is completely different than the route between you and a speedtest.net server nearest you.
Preferential Lane for Speed Test
Our experience also tells us that
Mobile or landline internet service providers often give preferential treatment on their network for speed test traffic. Because simply they know it is the first thing a customer would do when assessing the speed of their service.
Using the result from speedtest.net to estimate the bandwidth you have in general or the bandwidth you have in SpeedFusion is then no different than using the road condition of a preferential congestion-free highway to your nearest convenience store, to gauge your daily commute on the public road to and from work, where sadly accidents and traffic jam are the norm. This as you can see will not give you a useful estimation.
Peplink SpeedFusion Built-in Test Tools
What would then be a better tool to evaluating the SpeedFusion bandwidth? Your Peplink router has it built-in.
Your Peplink router has a built-in TCP and UDP speed test tools that enable you to evaluate the SpeedFusion bandwidth available from one point to another.
Go to Status > SpeedFusion on your Peplink router web admin page. There you will see a table of all the SpeedFusion connections this Peplink Balance or Pepwave MAX has. Identify the SpeedFusion connection you want to perform speed test on. To the far right, you will find a little speed-o-meter icon. Click on it to bring up the PepVPN Test and Analyser tools.
Two protocols we can use to perform a speed test.
Transmission Control Protocol (TCP) is one of the main transmission protocols of the internet. It is designed to provide reliable delivery. It uses packet loss as a measure of network congestion and will dial down the traffic when it sees packet loss.
For landline internet connection, TCP speed test will give you a good idea of how much SpeedFusion bandwidth is available between your Peplink routers.
If we are however doing SpeedFusion bonding on wireless or mobile 4G LTE internet, it may be a good ides to use UDP speed test instead.
User Datagram Protocol (UDP) is a transmission protocol designed for time-sensitive application such as audio/video streaming or VoIP. It does not have congestion control mechanism. It considers timely transmission more important than reliable delivery. It lets packet drop rather than requesting retransmission.
Wireless or mobile 4G LTE internet connections often have a higher and more volatile packet loss than landline connections. TCP may mistaken this fluctuation in packet loss as a sign of network issue and decide to dial down the traffic. This will give us a lower bandwidth result than the actual bandwidth available.
This is why, for wireless or mobile 4G LTE internet, UDP speed test will probably give you a better idea of how much SpeedFusion bandwidth is available between your Peplink routers than TCP speed test.
And that is not all Peplink has in store.
On top of the PepVPN Test tools, your Peplink router also features a PepVPN Analyser. It automates a series of TCP upload speed test on each of the possible paths between your Peplink routers.
For example in a SpeedFusion setup of one Peplink Balance with 1x landline internet and one Pepwave MAX with 2x 4G LTE, there will be 2 possible paths in total between them — going between landline internet #1 to 4G LTE #1, and between landline internet #1 to 4G LTE #2.
Whereas in a SpeedFusion setup of one Peplink Balance with 2x landline internets and one Pepwave MAX with 2x 4G LTE, there will be 4 possible paths in total between them — going between landline internet #1 to 4G LTE #1, between landline internet #1 to 4G LTE #2, between landline internet #2 to 4G LTE #1, and between landline internet #2 to 4G LTE #2.
The result of PepVPN Analyser is a table of the TCP upload speeds of each of these individual point-to-point paths, and of the bonded connection using all of these paths. The table will display the packet loss rates and latencies during the tests alongside the TCP upload speeds. This will be helpful in identifying connection with high- latency and/or packet loss that is dragging down the performance of the overall bonded SpeedFusion connection.
Speedtest.net as well as other online speed test services are handy in gauging your internet speed. For estimating SpeedFusion bandwidth however, for reasons discussed above, it may provide a false expectation and may do more harm than help.
Bonding gives you no more or even less bandwidth than one 4G LTE? See Evaluating SpeedFusion: Part 2.