How to Simulate Different Network Speeds for Mobile Apps and Websites Using JMeter

In most cases, mobile device users access the Internet through their cellular carrier networks, which vary in coverage and connection speed; therefore, it is essential to ensure that websites or applications can handle different mobile and tablet network speeds.

This article demonstrates how to control the simulated virtual users' bandwidth in JMeter load testing to achieve this.

By default, JMeter sends requests as quickly as possible, which is useful for generating load but unrealistic because real users pause between actions and are limited by network bandwidth.

Limit output bandwidth to simulate different network speeds

JMeter provides options to limit output bandwidth using two properties:

httpclient.socket.http.cps = 0
httpclient.socket.https.cps = 0

These properties apply to the HTTP and HTTPS protocols respectively; a value of 0 means no limit. The acronym cps stands for “characters per second”. Setting a value greater than zero adjusts the bandwidth accordingly.

The formula for calculating cps is:

cps = (target bandwidth in kbps * 1024) / 8

For example, to simulate GPRS downlink speed of 171 Kbits/s, the corresponding CPS value is 21888 (171 * 1024 / 8).

Add these two lines to the user.properties file (found in JMeter’s bin folder)

httpclient.socket.http.cps = 21888
httpclient.socket.https.cps = 21888

Restart JMeter for the configuration to take effect.

Pass property values via the -J command‑line parameter

Example command:

jmeter -Jhttpclient.socket.http.cps=21888 -Jhttpclient.socket.https.cps=21888 -t /path/to/your/testplan.jmx

Some popular bandwidth presets:

Bandwidth

cps value

GPRS

21888

3G

2688000

4G

19200000

WIFI 802.11a/g

6912000

ADSL

1024000

100 Mb LAN

12800000

Gigabit NIC

128000000

The article also lists additional JMeter topics and resources for further learning.