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I'm trying to test some QoS policies I'm implementing on a router between two networks. I have two linux servers, one on each network, and I'd like to simulate data transfer between them so I can see if the QoS is effective.

The data is mostly UDP, but being able to simulate TCP data would be useful as well.

I originally tried just piping /dev/urandom through netcat , but this just uses up as much bandwidth as it can and swamps the connection.

Is there a way of doing something similar, but allowing me to restrict the data rate to something specific?

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up vote 2 down vote accepted

If you're testing QoS, shouldn't you want it to use as much bandwidth as possible to make sure your policies don't swamp the connection? I suppose it depends what you're actually trying to accomplish..

In any case, you can use iperf which lets you set the bandwidth and do bandwidth testing.

-b, --bandwidth n[KM] set target bandwidth to n bits/sec (default 1 Mbit/sec). This setting requires UDP (-u).

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If this was an isolated network not being used for anything else, I'd agree. However, I managed to cause some other issues due to netcat chewing through all the bandwidth (means my QoS policies are not there yet!). Didn't know iperf could target bandwidth, I'll give that a go. – growse Jun 7 '13 at 8:18

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