[ns] Shaping & rate-limiting

[Jorge Manrique <jorge.manrique@upcnet.es>]

Hi all,
I posted two questions some time ago and now I see they are in some kind of strange format in the mailing list, so they couldn't probably be read easily.
If someone knows the answers to any of the questions please give me an answer, as I MUST simulate a network that uses shaping and rate-limiting.
1) I'm doing some simulations using the DiffServ module. I need to "shape" the traffic, that is, establish a rate limitation for a flow so that even if the traffic entering one node is higher the "shaper node" won't send traffic to the next hop above the established rate limit and it will buffer the rest of the packets until they are to be transmited according to the rate-limit even if there is available bandwidth in the link.
Is there a way to do this in NS? I searched into the DiffServ module, but the only thing I have found is addQueueRate, which can only be applied when using Priority Queuing and only limits the flow's rate when the link is congested; it doesn't seem to have any effect when there is available bandwitdh.
2) Related to this, I also want to simulate CAR, that is, dropping packets when they do not agree with a traffic policy. In the DiffServ module flows are compared to a traffic profile and marked accordingly, but they are buffered in the dsRED queues. I don't want to use different queues, but just drop non-conformant packets. Is that possible? How can I do that? I've thought of setting mRedMode as Droptail. Should that do the job? Any help will be greatly appreciated. 

Thanks a lot and best regards,

Jorge