Interpretation of iperf and iperf3 results, especially regarding speed.
After testing my ethernet connection with iperf3, I was wondering if my results are good and what a normal bandwidth should be. Therefore, I started to search for references.
My iperf3 test was done with a CAT6 cable that supports gigabit ethernet. iperf3 was running in TCP mode.
I found the following references and sources.
iperf indicating 940 Mbits/sec using cat 5 cable
~943 megabits per second is the theoretical max throughput you can get with TCP over IPv4 over 1000BASE-T using standard 1500 byte payloads, because of mandatory inter-packet gaps and other protocol overhead. So you're seeing full speeds as expected.
Source:
Proving the Network is Not the Problem With iperf
From the output above we see that the lowest observed throughput within a one-second interval was 927 Mbps, with an average rate of 939 Mbps. These numbers approach the maximum practical throughput for a 1 Gbps Ethernet link, and strongly suggest that the network is not at fault.
Source:
Iperf testing. What is considered a good result on a Gigabit network?
You should get around 940 Mbps if everything is working properly and you don't have any bottlenecks.
Source:
- https://www.reddit.com/r/HomeNetworking/comments/70sai8/iperf_testing_what_is_considered_a_good_result_on/
- https://www.reddit.com/r/HomeNetworking/comments/70sai8/iperf_testing_what_is_considered_a_good_result_on/dn5kmuy/
Using Iperf for measuring the network speed
The following stats show actual iperf measurements. Measurements were taken on a classic Ethernet hub, a Fast Ethernet switch and a Gigabit Ethernet. Iperf was first started without further options and then with the command
iperf -c 192.168.0.20 -w 512k -l 512k.
| Network type | Iperf default [MBit/s] | Iperf with options (see above) [MBit/s] | Theoretical maximum [MBit/s] |
|---|---|---|---|
| Ethernet hub | 7,5 | 7,5 | 10 |
| Fast Ethernet | 95 | 95 | 100 |
| Gigabit Ethernet | 346 | 948 | 1000 |
The measurements were performed between two systems with Intel Core 2 Duo CPU at around 2 GHz. Broadcom NetXtreme Gigabit NICs were used as network cards. The combination of Thinkpad R60 (Windows XP) and Apple Mac Mini C2D 1.83 MHz (Mac OS X Leopard) achieved about 940 MBit/s in the test.
Source:
- Expected bandwidth
- data transfer rate
- Is my bandwidth ok?
- Are my results good?
- iperf3 expected results
- iperf3 good results example
sudo apt install iperf3
Get server IP:
ifconfig
Server:
iperf3 -s
Client:
iperf3 -c SERVER_IP
iperf3 -s -V
The command above starts iperf3 in server mode. The -s activates the server mode and the -V is for enabling the detailed output (verbose). Other commands can be found with iperf3 help.
iperf3 -s -V > ~/iperf3-log.txt
The command above does the same thing as the one further above, except that it writes the output to the file iperf3-log.txt in the user's home directory in contrast to printing it on the console/ terminal (as the first command does).