Hello, There is one thing that stays in the deep of my brain (where i can't access) : which qdisc exactly send the paquets: the root or the leafs ? I explain: You must have a root qdisc then you have classes (don't care about how much) and leaf classes MUST have qdisc to send the bits in the howto 9.5.2.1 it's writen: "Packets get enqueued and dequeued at the root qdisc, which is the only thing the kernel talks to." In the FAQ of docum.org article "root qdisc - class - qdisc - filter", Stef Coene writes : "Each leaf class has exactly 1 qdisc attached to it that actual sends the packets." These are only 2 sources and everybody say the same thing. So which qdisc sends the trafic, the root or the leaf ? Or maybe the leaf sends the trafic to the root which sends it to the NIC ? Thank you in advance for answering Nice week end anyway Manu