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Questions tagged [iperf]

128 questions
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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 11 sudo tc class add dev f30e888e9a857_c parent 1:…
user3249763
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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.
arne.z
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Poor network performance on Server 2008 machines

I have a network consisting of about 40 Windows 7 machines (physical) and 2 servers (Virtual, ESX) which are Server 2008 Std ed (one is a SBS 2008 but they're the same 'under the hood'). Network is a gigabit. It appears I am having some issues w/…
user229774
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tcpreplay throughput on eth0 well below (iperf confirmed) max

I'm trying to replay captured UDP multicast packets at a rate of a couple of hundreds of Mbps, but it maxes out at about 86 Mbps. (For some strange reason, at other times during the day it consistently maxes out at one tenth of that rate, about 8.8…
Evgeniy Berezovsky
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Iperf multiple streams

I need to test my network between two sites using iperf. I'd like to open parallel streams sending data on different (let's say 5 defined) ports, with random length from 10-1000, with random 1-2 seconds breaks between every 3 seconds transmission.…
kozooh
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Interconnected switches Slow throughput

I am in charge of a network of which a portion of it looks like this: One DLink DGS-1210-24 (1) as the main switch. One DLink DGS-1210-16 (2) connected with cat5e 250 feet away connected on (1) One DLink DGS-1210-16 (3) connected with fiber 500 feet…
Nic
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File transfer - Bandwidth flickering for no reason

We are experiencing file transfer issues. I try to troubleshoot this problem but it is really hard. Here is a screenshot I took while transferring a file from my workstation to another server. The screenshot was taken from the workstation…
Jonathan Rioux
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IPerf - Reverse test

I'm trying to perform a test using IPerf but in a special case. Usually iperf client send data to iperf server, what I need in this case is the server send data back to the client in the same connection. I don't want a bidirectional test, as it does…
CarlosH
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Measuring network performance between Windows and Linux

I'm using iperf to estimate network performance between Windows and Linux. For TCP iperf shows 312 Mbits/sec from a Linux server to a Windows client, but it shows only 160 Mbits/sec from a Windows server to a Linux client. For UDP iperf shows 147…
Rom098
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iperf3 errors and retransmissions on ESXi

When running iperf3 to test a 100G connection between a VMware ESXi box and a TrueNAS Core box, I'm seeing the following on the ESXi box: The message "iperf3: getsockopt - Function not implemented" on every interval A large number of…
lunadesign
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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 Netgear GS752TP switch. Our router is a Ubiquiti…
laxer
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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: (Forward Data Transfer) Making Server 1 as iperf…
Rohit Lal
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Why udp has lower throughput than tcp?

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 much higher throughput than udp. However, as we know…
sarah sh
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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 years upon years. Help would be awesome! Sample…
Gutsygibbon
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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-94f4947e87753b8be193ca54d17dac24cac599fb Every one have two network…
aircraft
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