[Planetlab-users] Limiting bandwidth

[Davide Frey]

Hi all,
first I apologize if this question has already an answer somewhere on
the archive. I tried to look for one, but I found "plans to provide this
service in the next few weeks" in some mails from 2006, but I wasn't
able to locate any useful info in the documentation. So I thought I'd
post here.

I basically need to artificially limit the UDP bandwidth of some nodes
(outgoing, but also incoming) to simulate ADSL connections.

What I thought of doing for outgoing bandwidth is to have a queue in my
application and a thread that reads from the queue sends at a maximum
rate. Basically, after sending a packet, the thread sleeps for an amount
of time = PACKETSIZE/BW.

This should be Ok for outgoing bandwidth. but incoming bw is not as
trivial. I can't just drop packets when I receive them as this would use
the sender's bandwidth even for messages that "are  not sent". To do
things right, the sender should know the bandwidth of the receiver and
limit what it sends accordingly. Given that this looks a lot more
complicated to implement, I was wondering if there's a tool to achieve
this or if there's some configuration parameters on planetlab that allow
me to limit the bandwidth of specific nodes in my slice.

Also, I would appreciate comments on my outgoing cap implementation
described above. In particular, what should be dropped when the queue is
full? the head of the queue or the message being pushed?

thanks to all

Davide