Questions tagged [iperf]

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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?
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10 views

Fluctuating throughput numbers with iperf3 and bonding

I created a bond out of two interfaces of 10G with the following config in two servers: Bonding Mode: load balancing (xor) Transmit Hash Policy: layer3+4 (1) MII Status: up MII Polling Interval (ms): ...
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16 views

NIC GRO offload influence in TCP window size in Linux?

I am facing some, from my point of view, counter-intuitive results on some iperf3 tests between two 40Gbps interfaced servers (the rest of tcp stack config protocols are the same in the 2 servers). ...
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1answer
128 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 ...
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1answer
71 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: (...
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0answers
24 views

iperf3 throughput dropping suddenly after some seconds after boot

I've setup a Linux test environment with two servers, connected via Intel Corporation Ethernet Controller X710 for 10GbE SFP+ with each other. My iperf3 command lines look like this: client$ iperf3 -...
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1answer
58 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 ...
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2answers
157 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 ...
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1answer
57 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 ...
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1answer
1k 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
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1answer
255 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 ...
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1answer
131 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 ...
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0answers
164 views

Unable to test Network Performance using Iperf3 on AWS EC2

I aim to test my Network Performance using Iperf3 on AWS EC2 where I have 2 Amazon Linux 2 AMI CentOS ID_LIKE="centos rhel fedora" in 2 different VPCs according to this topology in which there are 4 ...
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2answers
4k 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 ...
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0answers
209 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 ...
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0answers
687 views

What can be done increase bandwidth from Citrix XEN guest to Citrix XEN guest on the same physical host?

Guest VM to guest VM bandwidth on a single Citrix 7.6 XenServer host caps out at about .6Gbits/s using UDP and 6Gbits/sec using TCP. UDP performance over restricted shared memory does not reach ...
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1answer
78 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
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1answer
242 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....
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1answer
1k 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 ...
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1answer
744 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 ...
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1answer
740 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 (...
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1answer
1k 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 ...
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2answers
1k 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 ...
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1answer
181 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
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1answer
581 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-...
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0answers
410 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 ...
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1answer
273 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: ...
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2answers
448 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
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1answer
66 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 ...
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0answers
813 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 ...
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2answers
319 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 ...
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1answer
4k 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 ...
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2answers
690 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 ...
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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 ...
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1answer
382 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 ...
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0answers
129 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 ...
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0answers
53 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 ...
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0answers
130 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 ...
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2answers
16k 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?
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3answers
4k 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
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1answer
3k 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 ...
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2answers
11k 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
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1answer
4k 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.
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1answer
946 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
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1answer
526 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 ...
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1answer
547 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 ...
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0answers
273 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 ...
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0answers
1k views

How slow can be a QCOW2 vm disk (proxmox/KVM) over NFS (dedicated 1Gbit)?

I'm running 3 proxmox 3.4 nodes using NFS shared storage with a dedicated 1GB network switch. root@lnxvt10:~# pveversion pve-manager/3.4-11/6502936f (running kernel: 2.6.32-43-pve) root@lnxvt10:~# ...
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0answers
2k views

Strange iperf3 behaviour with UDP streams

I am using iperf3 verson 3.0.11 to measure the throughput of a UDP stream between two virtual machines. The virtual machines are deployed via OpenStack. Of the physical hosts, one is located in ...
1
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3answers
14k views

No package iperf3 available CentOS

I'm trying to install iperf3 on a server to run some tests... Unfortunately I cannot. What do I need to do? Enable a repo or download a rpm file with wget? [root@localhost hodor]# yum install iperf3 ...