Dummynet cascade of pipes

[John Mok]

Hi,

I am new to Dummynet. I would like to setup a FreeBSD QoS box to replace 
the one using Linux IMQ. However, I have the following questions :-

1. Is it possible to cascade pipes, such that the bandwidth management 
could be easier by hierarchical control rather than flat-out? For instance,

pipe 100 is the total bandwidth 2Mbps of the serial link to Internet
pipe 110 cascade pipe 100 with a weight 8Kbps and ceiling 16 Kbps
pipe 120 cascade pipe 100 with a weight 32Kbps and ceiling 256 Kbps
pipe 130 cascade pipe 100 with a weight 384Kbps and ceiling 2Mbps
pipe 140 cascade pipe 100 with a weight 224Kbps and ceiling 2Mbps

Pipe 130 and pipe 140 are allowed to consume the total bandwidth if 
there is no other traffic, but would only get its share 224 / (8 + 32 + 
384 + 224) when all pipes are fully loaded.

2. Is there any FIFO queue rather WFQ? If there are 3 queues defined top 
sahre the bandwidth of pipe 110, how to make the traffic to go in FIFO 
manner?

Thanks a lot.

John Mok