Hi, I'm new to HTB and CBQ, and i want to try it. But i failed the first step: load modules. I patch the kernel 2.4.17 succesfully, add QoS support, and all QoS scheds in modules instead off kernel. make clean dep bzImage modules modules_install copy the new kernel reboot fine But when i : server:~# insmod sch_htb Using /lib/modules/2.4.17/kernel/net/sched/sch_htb.o /lib/modules/2.4.17/kernel/net/sched/sch_htb.o: unresolved symbol qdisc_get_rtab/lib/modules/2.4.17/kernel/net/sched/sch_htb.o: unresolved symbol unregister_qdisc/lib/modules/2.4.17/kernel/net/sched/sch_htb.o: unresolved symbol qdisc_put_rtab/lib/modules/2.4.17/kernel/net/sched/sch_htb.o: unresolved symbol register_qdisc/lib/modules/2.4.17/kernel/net/sched/sch_htb.o: unresolved symbol pfifo_qdisc_ops/lib/modules/2.4.17/kernel/net/sched/sch_htb.o: unresolved symbol qdisc_kill_estimator server:~# grep qdisc_get_rtab /boot/System.map c01f4ecc T qdisc_get_rtab c0286a20 ? __kstrtab_qdisc_get_rtab c028ad20 ? __ksymtab_qdisc_get_rtab Where is the problem ?? (i will try with all scheds _in_ the kernel) -- Grégory Duchatelet