Re: simulate delays and packet drops in tcp /udp

From: Andrew Morton (
Date: Tue Sep 03 2002 - 15:30:14 EST

Joe Knowling wrote:
> I'd like to be able to simulate network congestion and
> delays on a tcp / udp connection on a single host -
> essentially connecting via the loopback interface.
> Before
> going on to hack some kind of delay /drop layer I
> thought
> I'd check to see if there already is something
> available.

I did a thing which does that.

It uses the tun/tap device and some rather funky policy-routing
rules to route packets up through a userspace application. The
userspace app performs the delay and bandwidth limitation then feeds
the packets back into the kernel. It doesn't perform packet loss, but
that'll be easy.

The challenge will be working out how to make it go :( It was a
couple of years ago.
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