How to use iPerf to measure throughput on a SonicWall device?

12/20/2019 1,885 People found this article helpful 494,981 Views

Description

Prior to 5th generation appliances, SonicWall appliances did not utilize multi-core processors. This changed with the arrival of the NSA class units. Today, most SonicWall appliances have more than a single processor to process data that comes in and out of the firewalls. Each connection made through the firewall, (often referred to as a socket, or "thread"), will only be able to pass through a single processor. Units with a higher number of processors can process more simultaneous connections.

Due to this change in architecture, it is no longer possible to accurately test throughput with a single TCP connection through the firewall, as it was with earlier versions of hardware due to their monolithic CPU. The NSA and SuperMassive series of appliances utilize multi-core processors, which exponentially increase performance.

Because each of these connections are handled by a single core, it is necessary that throughput tests of SonicWall appliances involve multiple file transfers at the same time (where min number of files = # of CPU cores). A single transfer can only test the throughput of a single core. Many administrators mistakenly run an online throughput test when trying to determine the capacity of their firewall, and are baffled when the results are lower than they expected, not realizing that they only tested a single core.

Because of this we need to test bandwidth utilizing a tool capable of multiple simultaneous connections.

NOTE: iPerf is the tool we recommend for this testing.

Resolution

iPerf is a command line utility that is set up in a client server configuration. For WAN throughput testing you will need a computer connected to the WAN interface and one connected to the LAN interface.The utility is multi-platform compatible, and is available from https://iperf.fr. For the rest of this tutorial we are going to assume we are using a Microsoft Windows environment.

Once you have downloaded iPerf and extracted it to a folder, you will need to navigate to that folder with a command prompt.

To start the server you will need to type the following command on the device connected to the WAN.
iperf3 -s
Once the server is listening you will need to start the test. That is completed by typing the following command on the device connected to the LAN (Replacing the X's with the IP Address of your server). This will test your upload speed.
iperf3 -c X.X.X.X -P 40 -t 60
This will start the iPerf test to your server with 40 connections. And the test will last for 60 seconds. If you want to test download speed you will type the following command.
iperf3 -c X.X.X.X -P 40 -t 60 -R
Once you type the command it will begin the test immediately. Once completed you will see the following.

The lines indicating [SUM] are cumulative result of the test. And this is your Download or Upload speed depending on the test run.