Subject: Re: Simulation app?
To: Peter Eisch <>
From: Chuck Swiger <>
List: netbsd-users
Date: 05/22/2007 12:21:32
On May 22, 2007, at 11:56 AM, Peter Eisch wrote:
> Is there a tool native or pkgsrc that can be used to introduce  
> network delay
> based on the source or destination address?  I could see altq being  
> used to
> throttle usage, but I'd like to simulate both terrestrial and  
> satellite
> connections between interfaces on my netbsd router.
> I'd imagine this being a userland program that uses a tap interface  
> on each
> side of the router that includes a config with src, dst, delay triads.
> Any pointers someone can afford to spare?

ALTQ or IPFW+dummynet are the two common approaches to introducing  
network bandwidth management or adding latency, and you should be  
able to configure rulesets to match specific src or dst netblocks as  
needed.  It would not be impossible to write a userland tool to do  
something similar, perhaps using divert sockets the way the userland  
natd program works, or perhaps to use a proxy (either explicit or  
transparent proxy) approach instead.


PS: However, it's not clear whether NetBSD has imported IPFW+dummynet  
from FreeBSD; if not, then using FreeBSD as your platform might be  
better for this sort of testing....