Hi Phil, I agree that if you apply rate control to the client it would limit the packet generation, but the reason I say the queueing dynamics would override these affects is that rate control algorithm assume all packets have the same service rate. But since the queue is biased towards the forwarder the service rate of a client packet will be less than the service rate of a frowarded packet. Wouldn't the rate allocated to the client have to take this into account ?
I agree with the point you made on the segregation of queues its like applying a control algorithm on the queues itself. So would it make sense to have a single queue for clients and forwarded packets and serving them without bias (first come first serve) and allowing rate controllers to control their rates ? regards, Avinash On 3/23/07, Philip Levis <[EMAIL PROTECTED]> wrote:
On Mar 22, 2007, at 10:35 PM, Avinash Sridharan wrote: > Hi Phil, > But even if we apply rate controllers at the sources (say for each > of the clients) the inherent unfairness in the queuing dynamics > would over ride the effects of the rate controllers to provide > fairness. If you apply rate control to packet generation, then this is going to limit how many client packets are in the queue at any one time. How would queueing dynamics override these effects? > The point I am trying to make is to make transport layers work > with the forwarding engine that can ensure fairness there should be > a fair treatment of all packets in the queue. One way I would think > this could be done is to keep the client queue segregated from the > forwarding queue, and make the send task alternate between these > queues. Alternating between the queues most certainly would not provide fairness -- you give equal weight to packets you generate and *all* packets you forward. Nodes close to the root would have a higher throughput than those far. That being said, if you had two queues, you *could* control the rate at which you service them to provide fairness. But that's not any different than controlling the rate at which packets can enter a shared queue. Phil
-- Phd Dept. of Electrical Engineering University of Southern California http://www-scf.usc.edu/~asridhar
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