Pipe queues

[Luigi Rizzo]

On Mon, Dec 10, 2007 at 11:22:33AM -0800, Chuck Swiger wrote:
> On Dec 10, 2007, at 8:56 AM, rihad wrote:
> > Hi,
> >
> > I'm having a hard time to understand what pipe queues are with  
> > respect to bandwidth limitation. ipfw(8) and dummynet(4) manuals  
> > didn't help me much.
> 
> Pipes and queues are two different things; a pipe simulates a network  
> link, and a queue is used to hold packets which are backlogged because  
> they are arriving faster than the outbound link (ie, a pipe) can  
> transmit them.
> 
> > How does dummynet's traffic shaping function?
> 
> It uses a variant of weighted fair queuing.

actually the shaping uses a leaky bucket algorithm.
The weighted fair queuing is the queue management scheme used
when you have multiple queues attached to the same pipe

cheers
luigi