Andreas Schuldei wrote:
>
> to simulate a sattelite link, I need to add a latency to a
> network connection.
>
> What is the easiest and best way to do that?
>
> I wanted to do that using two tun devices.
> I had hoped to have a routing like this:
>
> <-> eth0 <-> tun0 <-> userspace, waiting queue <-> tun1 <-> eth1
yes, that works very well. A userspace app sits on top of the
tun/tap device and pulls out packets, delays them and reinjects
them.
The problem is routing: when you send the packet back to the
kernel, it sends it straight back to you. You need to rewrite
the headers, which is a pain.
A simpler approach is to use policy routing - use the source
and destination devices to override the IP addresses. Works
well. The code is at
http://www.uow.edu.au/~andrewm/packet-delay.tar.gz
It has its own variable bandwidth management as well
as variable latency. It's for simulating narrowband, high
latency connections.
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This archive was generated by hypermail 2b29 : Sat Jun 30 2001 - 21:00:21 EST