[Planetlab-users] Simulating network loss/latency?

[Emil Sit]

On Fri, 15 July 2005 at 16:12 (+0800), Teng Junbin wrote:
> I am performing an experiment on network streaming and to be realistic, I
> need to simulate network latency and packet (UDP) loss.

By definition, sending traffic between PlanetLab nodes is realistic.
It may not be indicative of what an "average user in Singapore" might
experience, but the traffic is going out over the real Internet.
Can you better characterize what you want to do?  Do you want to
see loss due to cross traffic in the core?  Congestion at the
source or destination?
  
> However, as far as I can see, Planetlab nodes are all fairly well connected
> and don't seem to have any issues with bandwidth.

There are certainly PlanetLab nodes that are not well connected.
For example, there are nodes in Lebanon, Russia, Brazil, etc that
do show long latencies to most other nodes.

> Someone suggested to me that I can open background "junk" traffic which will
> then bog down the bandwidth, resulting in "natural" packet loss.  However, I

If you want to simulate particular traffic and loss flows, perhaps
you should consider Emulab (www.emulab.net) or setting up ModelNet
(http://issg.cs.duke.edu/modelnet.html).

-- 
Emil Sit / MIT: CSAIL PDOS, SIPB, OLC / http://web.mit.edu/sit/www/