On Mon, May 4, 2015 at 8:22 AM, Haleema Sadia <[email protected]>
wrote:

> The issue is resolved now.. I was setting up the bandwidth and delay
> variable in the mininet custom topology that I created. Once I removed them
> the queues starting working. However, if I have different min/max rate for
> the queues the min rate threshold is not maintained.
>
> For ex, if min-rate is 4 Megabit and I specify the udp packet rate to be 3
> Megabit, the bandwidth on the server side(where the queue is being
> maintained) for iperf goes to 3 Megabit.
>
> Do you have any idea why?
>

I think you are misunderstanding the idea of "min-rate".  It is not going
to create traffic for you just to make the link utilized, which is
effectively what you are asking for.  If you tell iperf to create 3Mbps of
traffic, the QoS implementation isn't going to "pad" that with another
megabit to meet your min-rate threshold.

Min-rate is just used to reserve a "slot" of a given size - all other flows
traversing the interface that are *not* hitting this queue cannot consume
the "last" 4 megabits of available bandwidth, preserving that "minimum
rate" for flows which traverse this queue (this is a gross
oversimplification of how it works).  That being said, this generally
doesn't work under large traffic volumes as the tc stack starts to fall
over when you give it that much work.

--
Nick
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