Scalability of ALTQ

Bernhard Schmidt berni at
Thu Jan 13 03:03:35 PST 2005

On 2005-01-13, Max Laier <max at> wrote:

>> apparently when using subqueues pf adds up the realtime bandwidth of all
>> queues and compares it to the interface bandwidth. To my understanding
>> the sum of the bandwidth of all child queues should be compared to the
>> direct parent queue. Am I wrong here?
>> Of course I could increase the bandwidth parameter on vr1 to something
>> really hillariously high, but is this the thing intended?
>From the manpage:
>>      realtime <sc>
>>                  The minimum required bandwidth for the queue.
>                        ^--------------^
> So this is the guaranteed minimum bandwidth that must be available to the
> queue at any given time.  The makes it clear that the interface must be able
> to provided the combined realtime bandwidth of all child queues.

Okay, makes sense.

>>      upperlimit <sc>
>>                  The maximum allowed bandwidth for the queue.
>>      linkshare <sc>
>>                  The bandwidth share of a backlogged queue.
> That's more what you seem to want.

So my commited bandwidth is linkshare, and the burst is upperlimit? Is
there a good description on how these attributes influence hfsc's


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