Hi Phil, A few more questions more on the bandwidth allocation between the client and forwarder in the forwarding engine.
The forwarder effectively has a depth of FORWARD_COUNT (set to 5) in the FIFO queue and the client has a depth of 1. As you mentioned in your mail below this implies the client gets only 1/6 th of the bandwidth. Isn't this inherently unfair. In the sense that the forwarded packets would always get 5 times the bandwidth as compared to the source itself. I did a simple experiment with the following linear topology: 1<----2<----3 This was done on TOSSIM, I kept an application level queue of size 50 for the forwarder 2. Both 2 and 3 were generating packets that were destined for the sink 1. It turned out that for every 3-5 packets forwarded by node 2 to node 1 that originated from node 3 you would have a single packet forwarded sent from node 2 to 1. Thus the bandwidth allocation was quiet uneven. -Avinash On 3/22/07, Philip Levis <[EMAIL PROTECTED]> wrote:
On Mar 22, 2007, at 12:00 PM, Avinash Sridharan wrote: > So this means for a client the send queue size is one and for the > forwarded packets the send QUEUE size is FORWARD_COUNT ? > > Did I get this right ? since whenever a client forwards a packet > unless the previous packet has been sent out it cannot insert its > own packet in any case right ? > I think you're a bit confused; clients don't forward packets, they generate them. FORWARD_COUNT defines the number of forwarding packets a node can have in its queue. That is, packets it received from another node. CLIENT_COUNT defines the number of generated packets it can have in its queue. That is, the number of packets a higher layer has requested to send to a collection point. If a sending client wants a queue deeper than 1, then they can always put their own queue on top of its single entry in the CTP transmission queue. But the forwarding queue allocation discipline means that this client gets at most 1/Nth of the bandwidth. Phil
-- Phd Dept. of Electrical Engineering University of Southern California http://www-scf.usc.edu/~asridhar
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