Scheduler Mechnisms!

["Zhenyu Wu" <y030729@xxxxxxxxxxxx>]

Hello,

Normally, in addition to such qdisc scheduler mechanisms as FIFO, PQ, WRR, WFQ,
are there any more? Then, there is a confusion on scheduler in Linux enviroment:
Assume there is a qdisc, such as RED as a leaf qdisc in a router, we know, if
there is packet which want to enqueue the packet, the Function red_enqueue is
called, but when the packet leave the queue(when the Function red_dequeue is
called)? I think it is meaningless when the pack leaves the queue just it 
enterred
it. Is there anything need to be done betweent the packet's enqueue and dequeue?

Best,