This is so theoretical that not even Alexey (the main CBQ author) claims to
understand it. From his source:
David D. Clark, Scott Shenker and Lixia Zhang
Supporting Real-Time Applications in an Integrated Services Packet
Network: Architecture and Mechanism.
As I understand it, the main idea is to create WFQ flows for each guaranteed
service and to allocate the rest of bandwith to dummy flow-0. Flow-0
comprises the predictive services and the best effort traffic; it is handled
by a priority scheduler with the highest priority band allocated for
predictive services, and the rest --- to the best effort packets.
Note that in CSZ flows are NOT limited to their bandwidth. It is supposed
that the flow passed admission control at the edge of the QoS network and it
doesn't need further shaping. Any attempt to improve the flow or to shape it
to a token bucket at intermediate hops will introduce undesired delays and
raise jitter.
At the moment CSZ is the only scheduler that provides true guaranteed
service. Another schemes (including CBQ) do not provide guaranteed delay and
randomize jitter."
Does not currently seem like a good candidate to use, unless you've read and
understand the article mentioned.
Take our 
