Measuring TCP delay from Linux kernel

TCP does not prioritize traffic like IP. When there are a lot of TCP background connections opened that are uploading data (like when BitTorrent is seeding in background) delay may occur for a...

How to specify iperf client port

Is there a way to force an iperf client to use a specific port number as its outgoing port instead of letting iperf on choosing a random port to use?

iperf, sctp command not recognized in command-promt

I'm using iperf3 that is supposedly a rewritten version of iperf. Reason why Im using this is because I love iperf when it comes to TCP and UDP throughput and I now want to test SCTP throughput...

The average Jitter calculated in Iperf

In the RFC 1889 the delay jitter is given by J=J+(|(Rj-Sj)-(Ri-Si)|-J)/16 I use iperf to measure delay jitters between two network nodes. I got [ 3] 0.0- 1.0 sec 18.7 KBytes 153 Kbits/sec ...

Speed up rsync with Simultaneous/Concurrent File Transfers?

We need to transfer 15TB of data from one server to another as fast as we can. We're currently using rsync but we're only getting speeds of around 150Mb/s, when our network is capable of 900+Mb/s...

Poor HDFS performances: "Slow BlockReceiver write packet to mirror"

I'd like to submit a strange behavior while instanciating another new Hadoop cluster, on a new hardware stack. Once everything got installed, as soon as we try to perform any I/O operation on...

Mininet: iperf fails + can't add flows in user-space switch

I am new to mininet and SDN. Following is an issue I came across while exploring iperf command. Set up a topology with three hosts and a user-space switch with following command: $ sudo mn --topo...

iperf Server and Client Differences

Forgive me if this is the wrong place - this is my first post. I've set up a network in Mininet - created two nodes with the same bandwidth and delay (Bandwidth: 10Mbps, Delay: 10ms). When using...

How can I stop iperf server when it finishes?

Once the client finishes the process is automatically closed. I would like to do the same thing in the server side, because I want to automatize some processes, but the server side finishes but...

springApplicationAdminRegistrar : Invocation of init method failed: nested exception is javax.management.InstanceAlreadyExistsException

when trying to run my spring app which usesClassPathXmlApplicationContext after running spring boot, I am getting this exception: 2016-12-25 01:24:53.033 WARN 7992 --- [nio-8089-exec-1]...

run iperf in background and redirect output to a file

I am trying to start iperf server in background and redirect the output to a file. But it is not working. server: iperf3 -s -D >> /tmp/listen.txt or iperf3 -s -D >...

Parsing a non-regular command output

I have the following output of iperf version 2 running on LEDE OS. I am trying to parse the output to get the number before the Mbits/sec which is the average throughput of the IPERF session....

How to check network speed using cmd in Windows 7?

I need to check network speed of a link between my PC and a server. I cant use any 3rd party tool like Iperf etc. Is there any way I can calculate network speed using any command on cmd?

iperf error: connect failed: no route to host

I have installed same version of iperf (2.0.5) on 2 different ubuntu systems. But when i execute command iperf -s -p 45678 on one system and iperf -c 172.18.41.17 -p 458 -t 10 on another system....

iperf TCP much faster than UDP, why?

I am wondering why iperf shows much better performance in TCP than UDP. This question is very similar to this one. UDP should be much faster than TCP because there are no acknowledge and...

Why iperf bandwidth is highter than dd->netcat

I want to measure actual speed of 1Gb Ethernet interface on my embedded device with ARM cortex-A8 two-core 600MHz processor, connected to PC on the other side. I've tried to check it with iperf...

High-performance TCP Socket programming in .NET C#

I know this topic is already asked sometimes, and I have read almost all threads and comments, but I'm still not finding the answer to my problem. I'm working on a high-performance network library...

sending packets from iperf packet generator in continuous mode

Can we send packets from iperf generator in a continuous mode? Currently, I am sending packets in a burst mode by using command iperf -c 10.0.0.2 -u -b 1m -t 1 where u is UDP packets 1m is...

How to create a dynamic range for loop?

I aim to create a dynamic range of a python loop. I know once the end range is computed only once, when it is passed as an argument to the range generator. However, this an example: i = 1 for i in...

Getting real time output from iperf3 using python's subprocess

This is a follow-on to: https://stackoverflow.com/questions/803265/getting-realtime-output-using-subprocess I'm trying to use subprocess to capture output from iperf3 in real time (using python...

iperf3 - Meaning of Retr column in TCP measurement

Sorry for asking this topic, but after reading the tool's documentation and the similar ticket to my question (https://github.com/esnet/iperf/issues/343), I still don't really understand/know the...

Aeron basic pub/sub pair connects on same host, fails across hosts

I am running the BasicPublisher/BasicSubscriber pair from https://github.com/real-logic/aeron binding them to the same multicast group+port. When they run on the same host they connect, but when...

Why dont bpf redirect work correctly?(XDP)

I write a simple Program Like this: SEC("tc_redirect") int _egress_redirect(struct __sk_buff *skb){ return bpf_redirect(5,0); // redirect all egress packets to interface 5 } # tc filter add...

Thousands of TimeoutExceptions after switching to Redis Enterprise

We recently attempted to switch from Azure Redis to Redis Enterprise, unfortunately after about an hour we were forced to roll back due to performance issues. We're looking for advice on how to...

iperf2 latency is a two way or one way latency

iperf2 (version 2.0.9) reports latency in its output as shown below. Is it a two-way latency or one-way latency measurement ? Server listening on UDP port 5001 with pid 5167 Receiving 1470 byte...

Use iperf and ping at the same time mininet

I just started a course on Computer Networks and my first assignment provides me with mininet script of a simple star topology, and asks me run an iperf measurement between h1 and h2. While the...

how to modify Iperf TCP connection timeout?

I am using mininet for emulation of a network. My network has a delay of 3000ms(linear topology of 3 switches).When I tried to do iperf I got Connection failed : No route to host error in client....

Generate traffic and measure qos parameters in custom mininet topology using Ryu Controller

I'm working on tweaking and testing QoS capabilities in SDN. I've tried POX and Ryu controller and run some custom topologies in mininet. However I need help for generating traffic in mininet...

ActiveMQ Artemis master can't detect slave

I am new to ActiveMQ Artemis and trying to configure master-slave setup. In my scenario, I am using one master and one slave. Master's broker.xml looks like: <configuration xmlns="..."> <core...

Flutter (Dart) ffi - Aplication freezes during processing external library methohd

I am using C library iperf3 to measure network. When I start network testing my aplication freezes and wait for results. I tried async and threads but any progress. Any advise? I'd like to run my...