Help Center/ Direct Connect/ User Guide/ Monitoring and O&M/ Using iPerf3 to Test the Bandwidth Availability of a Connection
Updated on 2026-07-08 GMT+08:00
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Using iPerf3 to Test the Bandwidth Availability of a Connection

Scenario

After a connection is established between your on-premises data center and the cloud, you need to test the connection performance to ensure that it can meet your service requirements.

This section describes how you can use iPerf3 to test the bandwidth of a connection.

Prerequisites

  • The connection between your on-premises data center and Huawei Cloud has been established, and the routes have been configured.
  • The following devices and resources are available:
    • A network access device in the on-premises data center, which functions as the client or server in iPerf3 tests

      Example IP address of the network access device: 192.168.0.1

    • Six ECSs that can access the Internet, which function as the clients or servers in the iPerf3 tests. They establish control connections with the network access device in the on-premises data center to transmit test configuration information and test results.

      In this example, the six ECSs use the flavor c7.large.2 and image CentOS 8.2 64bit (40 GB), and their IP addresses are from 172.16.0.2 to 172.16.0.7.

Setting Up the Test Environment

Install iPerf3 on the on-premises network access device and on the six ECSs. The following describes how to install iPerf3 on an ECS.

  1. Log in to the ECS.
  1. Install iPerf3.
    1. Download iPerf3. 
      yum install iperf3
    2. Check whether the installation is successful. 
      iperf3 -v

      If the version information is displayed, the installation is successful.

Using IPerf3 to Test the Bandwidth of a Connection

IPerf3 Overview

iPerf3 is an open-source, lightweight, and cross-platform network performance test tool. It measures the bandwidth throughput, packet loss rate, delay jitter, and packets per second (PPS) over TCP and UDP. It is an industry-standard tool for testing the bandwidth of enterprise physical connections, Direct Connect connections, backbone networks, and private networks.

Client-server model: The server at one end starts listening, and the client at the other end connects to the server and sends test packets.

Table 1 describes the parameters related to iPerf3.

Table 1 iPerf3 parameter description

Parameter

Description

-s

A server-specific parameter. It indicates that iPerf3 runs in server mode.

-c

A client-specific parameter. It indicates that iPerf3 runs in client mode.

-i

The interval between reports, in seconds.

-p
  • Server: The listening port on the server. The default value is 5201. Both TCP and UDP are listened on.
  • Client: The port for the client to connect to the server. The default value is 5201. If the -u parameter also exists, the connection is initiated through UDP. Otherwise, a TCP connection is used by default.

-u

UDP is used to send packets. If this parameter is not specified, TCP is used.

-l

The length of the read/write buffer. The recommended value is 1,400 for testing the bandwidth and 16 for testing the packet forwarding performance.

-b

The bandwidth (in bit/s) used if a UDP connection is established.

-t

The total transmission time, in seconds. It is the duration for iPerf3 to repeatedly send data packets of a specified length within a specified period. The default value is 10 seconds.

-A

CPU affinity. You can bind the iPerf3 process to the logical CPU with the corresponding number to prevent the iPerf3 process from being scheduled among different CPUs.

Testing the Bandwidth of the On-premises Network Access Device That Functions As the Server

  1. Run the following commands on the on-premises network access device to start the iPerf3 process in server mode and specify different ports: 
     iperf3 -s -i 1 -p 16001 
 iperf3 -s -i 1 -p 16002 
 iperf3 -s -i 1 -p 16003 
 iperf3 -s -i 1 -p 16004 
 iperf3 -s -i 1 -p 16005  
 iperf3 -s -i 1 -p 16006
  2. Run the iperf3 -u -l 1400 -b 100m -t 120 -c server_ip -i 1 -p port command on each ECS to start the iPerf3 process in client mode and specify different ports of the on-premises network access device.

    Example commands are as follows:

     iperf3 -u -l 1400 -b 100m -t 120 -c 192.168.0.1 -i 1 -p 16001 #First ECS
 iperf3 -u -l 1400 -b 100m -t 120 -c 192.168.0.1 -i 1 -p 16002 #Second ECS
 iperf3 -u -l 1400 -b 100m -t 120 -c 192.168.0.1 -i 1 -p 16003 #Third ECS
 iperf3 -u -l 1400 -b 100m -t 120 -c 192.168.0.1 -i 1 -p 16004 #Fourth ECS
 iperf3 -u -l 1400 -b 100m -t 120 -c 192.168.0.1 -i 1 -p 16005 #Fifth ECS
 iperf3 -u -l 1400 -b 100m -t 120 -c 192.168.0.1 -i 1 -p 16006 #Sixth ECS

Testing the Bandwidth of the On-premises Network Access Device That Functions As the Client

  1. Run the iperf3 -s -i 1 -p 16001 command on each ECS to start the iPerf3 process in server mode and specify the port.
  2. Run the following commands on the on-premises network access device to start six iPerf3 processes in client mode: 
     iperf3 -u -l 1400 -b 100m -t 120 -c 172.16.0.2 -i 1 -p 16001
 iperf3 -u -l 1400 -b 100m -t 120 -c 172.16.0.3 -i 1 -p 16001
 iperf3 -u -l 1400 -b 100m -t 120 -c 172.16.0.4 -i 1 -p 16001
 iperf3 -u -l 1400 -b 100m -t 120 -c 172.16.0.5 -i 1 -p 16001
 iperf3 -u -l 1400 -b 100m -t 120 -c 172.16.0.6 -i 1 -p 16001
 iperf3 -u -l 1400 -b 100m -t 120 -c 172.16.0.7 -i 1 -p 16001

Analyzing the Test Result

After the iPerf3 process on the client is executed, the following information is displayed. The packets per second (PPS) of the tested link can be calculated using the formula: PPS = Number of packets received by the peer end/Time.

[ ID]  Interval        Transfer    Bandwidth      Jitter    Lost/Total Datagrams 
[  4]  0.00-10.00 sec  237 MBytes  199 Mbits/sec  0.027 ms  500/30352 (1.6%) 
[  4]  Sent 30352  datagrams

The following table describes the fields in the command output.

Field

Description

Transfer

Transmitted data volume

Bandwidth

Bandwidth of the connection

Jitter

Jitter

Lost/Total Datagrams

Number of lost packets/Total number of packets (packet loss rate)
Parent Topic: Monitoring and O&M