Questions tagged [iperf]
The iperf tag has no usage guidance.
111
questions
2
votes
0answers
19 views
Asymmetry in Linux VM transfer rate
I have two Linux VMs, let's call them VM1 and VM2.
I have on VM1 an 80 Gb file.
When I try to transfer this file from VM1 to VM2 the transfer rate is almost 256 Mb/s.
scp 80Gblargefile VM2:/home/...
0
votes
1answer
20 views
iperf3 not consistent across different OS'es
I have connected two rooms via a 10Gbit fiber connection. The connection has one MikroTik switch with four SFP+ on one end (room A) and an Ubiquiti Unifi 24 ports with two SFP+ (room B).
On Room A, I ...
0
votes
0answers
8 views
How can I simulate UDP fragementation for network testing?
Is there a way to use iperf3—or another similar tool—to generate fragmented UDP packets?
I suspect my firewall isn't reassembling them properly.
0
votes
0answers
32 views
append date and time before each line in a text log file in windows 10
I want to append date and time before each line in a text log file in windows
I run iperf command in cmd in windows 10.
iperf.exe -c192.168.5.199 -u -t4 -i1 -f Kbytes -w1024k -b1024k >> client-...
1
vote
0answers
21 views
iPerf3 - normal and reverse measurement in the same instance
I can start a normal measurement (with 192.168.1.2 being the server) with
iperf3 -c 192.168.1.2
and a reverse measurement with
iperf3 -c 192.168.1.2 -R
Is there any way I can do both a normal and a ...
0
votes
0answers
99 views
Getting 2g speeds on hyper-v VM through a 10g nic
I'm testing my speeds using IPERF as I've recently installed a 10G cisco switch and intel 10g NIC's on some servers to communicate with a nas server.
I noticed my reads and write were awful so I've ...
0
votes
0answers
14 views
Measuring speed of multiple OpenVPN servers
Use-case: I was provided with a bunch of OpenVPN configs that I can connect to, but the speed of the different servers vary to a great extent. And no way was provided to check the speed from provider.
...
0
votes
0answers
22 views
Swanctl rw scenario: Better iperf3 performance running [rw --> gw --> client] than [rw <— gw <— client]
I'm testing out some StrongSwan scenarios, (specifically this one) and I've discovered something interesting, when running iperf3 -c (client) from the roadwarrior Carol and iperf3 -s (server) from the ...
1
vote
0answers
25 views
iptables tool to measure latency instead of bandwidth
I'm trying to measure the latency of having a lot of iptables rules.
I tried to use iperf but I think that bandwidth is not what i want.
Any help with this?
1
vote
1answer
224 views
FreeNAS + LAGG Slow Transfer?
I built a new file server that should be way overbuilt for its purpose. It has 2 Intel(R) Xeon(R) CPU E5-2660 v3, with 128GB of ram and it is running LCAP through an Intel X540T2 network card to a ...
0
votes
1answer
297 views
Why is there a difference in speed of forward and reverse traffic over 10 G network in iperf tool
I have a 10G network setup between my two servers (say, Server1 and Server2) and I'm using iperf tool to measure the bandwidth of the network.
Here are test cases that I performed,
Test Case 1: (...
0
votes
1answer
146 views
variable number of lost UDP packets reported by iperf, linux scheduling?
I am testing a connectivity with an iperf server (iperf version 2.0.13 (21 Jan 2019) pthreads) running on a Bananpi M2+ single-board computer (Debian, 5.1.1-BPI-Kernel #1 SM). For different target ...
1
vote
2answers
735 views
Why udp has lower throughput than tcp? [duplicate]
I am measuring the tcp and udp throughput by iperf3. I run iperf3 in virtual machines, one as server and the other as client. The VMs are connecting via 10 Gbps link. The results show that tcp get ...
0
votes
1answer
95 views
Using trickle/trickled to limit bandwidth throughput of iperf3
I'm doing some throughput testing on some radio units that have narrow channel bandwidth settings (for example sub 250KHz bandwidth). During my testing of iperf3, I noticed that the slowest speed it ...
1
vote
1answer
5k views
using Iperf3 to test upload and download
How to use Ipfer3 to test upload and download speed or in other words which data of the output given below represents upload and download speed ?
Iperf3 output
3
votes
1answer
713 views
using random ports with iperf/iperf3 [closed]
I am using Iperf/iperf3 -c remotehost which is
iPerf3 is a tool for active measurements of the maximum achievable bandwidth on IP networks. It supports tuning of various parameters related to ...
0
votes
1answer
241 views
At Iperf3, TCP weird behavior
I am a newbie network engineer.
I did a small experiment with iperf3. But I run into a small problem.
(1) My question.
I think TCP flow do not act properly despite of its congestion control.
The flow ...
2
votes
2answers
12k views
How to start iperf3 server in UDP mode?
I would like to test UDP connectivity with iperf3 but do not know how to start it in UDP server mode.
iperf3 -s only opens a TCP socket:
root@srv ~# lsof -i -P | grep iperf3
iperf3 21030 ...
1
vote
0answers
421 views
socat tun device very low throughput
I was tinkering around with socat and tried to use socat for creating a TUN device for tunneling between two debian stretch servers. However, throughput seemed very low and comparing with iperf ...
0
votes
1answer
178 views
Issues with Cisco IPSec VPN speed. Fast uploads, slow downloads from external to internal servers
We are using a Cisco ASA5516, configured with a IPsec (IKEv1) split tunnel VPN.
When uploading files to a server behind the firewall, the transfer speeds are normal (up to 10mbps).
When downloading ...
2
votes
1answer
650 views
Why am I only achieving 2.5Gbps over a 10Gbe direct connection between 2 machines?
I have 2 machines directly connected to each other with a 7 foot Cat6a ethernet cable (included in the box of the NIC cards). The PCIe x4 NIC I bought and in both machines is this: https://www.amazon....
2
votes
1answer
2k views
How can iperf reporting packet loss in udp
Iperf is the well known tool to calculate throughput. When i tried udp throughput using iperf on my linuxpc, It reported that 10% of packet loss.
In UDP protocol, data gram did not receice any ...
0
votes
1answer
1k views
iperf3 UDP not reliable with iptables drop random
I'm performing some local test on my network with iperf3 using UDP connections between 2 Ubuntu 18.04 hosts. But it seems that the UDP iperf3 connections it is not robust to support a random packet ...
0
votes
1answer
876 views
Low bandwidth when Iperfing data thorugh IPSEC tunnel
We have two server connected next to each other. When we're iperfing each other through 'simple' physical interaces - we're getting ~5GB/S of bandwidth. But when im sending traffic through tunneled (...
1
vote
1answer
2k views
How can I use an iperf output and only grep Interval and Bandwidth?
I am trying to get the output from the command
iperf -c 10.0.0.1 -t 3600 -i 2
And only need the Interval and bandwidth fields listed for the entire hour of logging.
I haven't used grep or awk in ...
0
votes
2answers
2k views
Undefined iperf3 ports?
I am trying to identify all of the ports affiliated with an iperf3 UDP session and am noticing that the TCP handshaking uses an undefined(?) port on the iperf3 server.
Is there a way to specify all ...
0
votes
1answer
230 views
Iperf2 capture received promiscous mode traffic Not Multicast
I want to capture all traffic in my Iperf server that I listen for promiscously, even if I am not the intended IP.
I know you can do this with Multicast addresses, but I do not want to follow that ...
1
vote
1answer
825 views
The FastNetMon client why not show the Incoming and Outgoing traffic?
I use VMWare created two VMs on my Windows Server.
two VM all are CentOS-7.2.
My FastNetMon version is bellow:
/opt/fastnetmon/fastnetmon --version
Version: 1.1.3 master git-...
1
vote
0answers
536 views
I test the Iperf failed
In my Server(CentOS7.2, address is 103.193.202.2), I run the iperf server:
# iperf -u -s
------------------------------------------------------------
Server listening on UDP port 5001
Receiving 1470 ...
0
votes
1answer
327 views
ieprf vs iperf3 metrics does not match
I am not a network expert but I was measuring the network between to physical hosts using iperf and I got different results depending of the version I was using.
Server configuration:
CPU:
...
1
vote
2answers
574 views
How to measure bandwidth per cpu utilization [closed]
I'm trying to measure efficiency of the networking system and looking for a tool that either allows to limit max bandwidth for each test or, ideally, limit cpu utilization. At the end I need to have ...
0
votes
1answer
79 views
Can ARP expire mid iperf connection?
If one runs an iperf connection between a node 'A' and a node 'B' is it possible that the arp entry expires from one of the nodes. [I have a simple mininet topology and while running an iperf ...
1
vote
0answers
1k views
Low network speed with small packets
Using iperf3 to test the network with --length 1000 --no-delay:
iperf3 --interval 1 --time 3 --no-delay --length 1000 --parallel 100 --client 10.0.0.3
Result:
[SUM] 0.00-3.00 sec 835 MBytes ...
0
votes
2answers
391 views
iperf bandwidth less than interface speed
I used linux bonding driver to bond 2 NICs in mode 6 in client PC.
ethtool ethX shows speed =1000
ethtool bond0 shows speed =2000
but when i use iperf
bandwidth of eth0 = 934Mbps
bandwidth of eth1 ...
0
votes
1answer
5k views
How to increase bandwidth of bonding interface in mode 6?
I am new to Linux Bonding Driver. I have configured a bond in mode 6 which combines 2 ethernet interfaces. Their individual bandwidth is 937Mbps and 700 Mbps. But when both the interfaces are up, the ...
0
votes
2answers
921 views
What's the operation about iperf udp
I'm trying to doing some bandwidth test by run iperf on my device,
My Network Max Bandwith is 100 Mbps
(test by speed test CLI - https://github.com/sivel/speedtest-cli)
And I ran the iperf UDP ...
6
votes
0answers
1k views
Why multicast UDP can be slower than unicast UDP?
I have two machines (with Centos 7.3 on both) connected via 1G switch.
When I measure UDP thoughput between macines with iperf it gives about 850 Mbit/s.
However when I measure multicast UDP thoughput ...
0
votes
1answer
415 views
LACP bond work intermittently on Cisco N5000
Our clients are using Centos 7.1 and 7.3. They are two 10GB card bonded to make a 20GB link. Each of the network card is connected to a pair of Cisco N5000 switch. While running cp or iperf, I can see ...
1
vote
0answers
145 views
What network setting could impact iperf3 results?
I am making some bandwidth tests to set a baseline for some other tests and I have a behaviour I cannot understand. The tests are done with iperf3 on Linux (with and without -R to get both up- and ...
2
votes
0answers
55 views
Measuring effectiveness of qdisc
I am trying to set the incoming and outgoing bandwidth of a particular interface. I set the outgoing bandwidth in the following way.
sudo tc qdisc add dev f30e888e9a857_c handle 1: root htb default ...
1
vote
0answers
135 views
slow single connection between two otherwise fast machines
I'm having trouble with larger file transfers from one of our virtual servers to our office network. The virtual server acts as a VPN server, therefore we call it "VPN", but the usage of VPN is not of ...
1
vote
2answers
19k views
How to set the UDP Packet Size with iperf3?
How to set the UDP Packet Size with iperf3?
The flag "-M" does not work with iperf3. Is there an alternative?
0
votes
3answers
5k views
IPERF 2.0.8/2.0.9 in Windows - "connect failed: Connection refused
I've been using iperf for some time but at present day i need to use the birectional test using -d or -r in the iperf command. The thing is that i always have "Connect failed: Connection refused" when ...
1
vote
1answer
4k views
Why the bandwidth is not ~10G?
I originally posted on "Network Engineering", but I was told to ask here.
I have 2 servers connected with 10G cable between them directly. I need to know that the connection is good and it has indeed ...
2
votes
2answers
14k views
iperf3 error - unable to create a new stream: permission denied
I am new to using iperf but others in my company use it but today it is acting strangely.
From the server:
iperf3 -s
which results in cmd showing:
Server listening on 5201.
From the client:
iperf3 --...
1
vote
1answer
5k views
What's the default TCP window size of iperf3?
Does anyone know what's the default TCP window size for iperf3? It is not mentioned in the manual and I also can't find it in the output, when running a test.
0
votes
1answer
1k views
Iperf3 keeps hanging when running UDP test
I wrote a Python program that runs iperf3 in a for loop with different datagram sizes. I am using Python's subprocess.call function to run iperf3 like this:
iperf3 -u -c 185.82.21.60 -b 100M -t 5 -l ...
4
votes
1answer
619 views
Segmentation fault when running nuttcp inside Docker
I am measuring the UDP throughput between two Docker containers that are connected by Docker's native overlay network. I already used iperf but also want to measure the throughput with nuttcp. But ...
7
votes
1answer
631 views
Right way of measuring overlay network performance
I am currently examining the performance (especially UDP throughput) of different Docker overlay networks. I do this by creating point-to-point connections between two hosts that are connected with a ...
1
vote
0answers
329 views
iperf actual send rate always lower than the expected target bandwidth until some equilibrium reached. Why?
I did an UDP iperf 2.0.5-Ubuntu test between two VMs on the same hypervisor. As can be seen in the iperf output below I started my first test with "-b 686M" flag. However, iperf reported that it was ...
