Questions tagged [bandwidth]

In computer networking and computer science, bandwidth, network bandwidth, data bandwidth, or digital bandwidth is a measure of available or consumed data communication resources expressed in bits/second or multiples of it (kilobits/s, megabits/s etc.).

Bandwith

In computer networking, bandwidth in bit/s sometimes defines the net bit rate (aka. peak bit rate, information rate or physical layer useful bit rate), channel capacity, or the maximum throughput of a logical or physical communication path in a digital communication system. For example, bandwidth tests measure the maximum throughput of a computer network. The reason for this usage is that according to Hartley's law, the maximum data rate of a physical communication link is proportional to its bandwidth in hertz, which is sometimes called frequency bandwidth, spectral bandwidth, RF bandwidth, signal bandwidth or analog bandwidth.

Common Misconception

In website hosting, the term "bandwidth" is often[citation needed] incorrectly used to describe the amount of data transferred to or from the website or server within a prescribed period of time, for example bandwidth consumption accumulated over a month measured in gigabytes per month. The more accurate phrase used for this meaning of a maximum amount of data transfer each month or given period is monthly data transfer.

source: wikipedia

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Limiting network throughput of an already launched process ? (Linux/FreeBSD)

Is there any utility to limit the network throughput of a process after it has been launched? Simple example: you note that a user takes all your upload bandwidth using scp and you'd like to limit the rate or decrease the priority of the transfer. I…
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How long does it take for an iptables rule to apply?

How long does it take for an iptables rule to apply? I use a script with the code below in an attempt to block hosts, but they don't appear to take immediately. Is there some delay, is iptables not working or is the code just plain…
vfclists
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Monitor Internet bandwidth

We have an IPCop firewall/proxy installed in our network, and although I can use iftop to somewhat take a look at how the clients are using the Internet, is it possible to monitor it from outside the proxy with something like ntop? Note that I'm not…
Ivan
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Simulate slow connection between two ubuntu server machines

I want to simulate the following scenario: given that I have 4 ubuntu server machines A,B,C and D. I want to reduce the network bandwidth by 20% between machine A and machine C and 10% between A and B. How to do this using network…
Yahia
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netcat throughput low but iperf high

I was testing the throughput between two pcs, connected on the same router, one with 100mbps lan, the other with 54mbps wifi. Here is the interesting part: using nc, I get 2.63MB/s when sending from A to B (measured with pv -r|nc ipB) using iperf,…
george
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Monitor SSH-traffic per user

We have a backup application that runs once every 12 hours. Multiple servers, desktops, and laptops connect to an EC2-instance and push a backup via SFTP using their own log-in credentials. If they need to recover a file, they can browse files via a…
Bart De Vos
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Amazon EC2 bandwidth charges in case of unwanted incoming traffic(ddos/flood)?

What happens if my EC2 instance gets ddosed/flooded, which could potentially go up to tens of gigabytes an hour(and even more) of undesired incoming traffic, will i be charged for this traffic? My guess is yes, but what can i do in such nightmare…
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How to find the bottleneck while transferring huge files between 2 hosts

We frequently need to transfer huge files (upwards of 50 GB) between two hosts, and the transfer rate never seems to reach the expected throughput for the network. There are several points which could be the bottleneck, but each of their theorical…
Fred
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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 root 3u IPv4 15606995 0t0 TCP *:5201…
WoJ
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Slow network speeds - what should I check?

Users are reporting that it's taking a long time to access files on the network, browse intranet sites, etc. What should I check?
Jon Galloway
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How to estimate network data transfer volume for a mysql database

When planning to port my application (Java+Tomcat+MySql) to a cloud hosting, I've found that one important factor to consider is the volume of data transferred to/from the database, as it is limited by cloud providers. I haven’t found a convenient…
pablochacin
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Does anyone know the bandwidth available for different EC2 Instances?

Hi I have heard that the small EC2 instances are limited to around 35mbit/s. Does anyone have any figures for the different instance types and the size of their pipes? We will be planning on using elastic load balancing but I'd really like to know…
scsmith
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When downloading two files, why does the second one not suddenly speed up after the first one finishes?

I have noticed that when I am downloading several files at a time, and one of them finishes, the bandwidth that it was consuming is not immediately apportioned to the others. For example, if I have two files being downloaded at 100 Kb/s each, and…
Pedro
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How should I manage per-user bandwidth?

Users often run bandwidth intensive applications - peer-to-peer applications, video, etc. Do you monitor and/or cap per-user bandwidth?
Jon Galloway
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Limit VMware Virtual Ethernet bandwidth

I'm looking to simulate a 56KB modem connection in a VMware Workstation virtual machine. I remember reading this was possible, but forgot how?
Josh
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