A.over leased lines， use the multilink ppp command to reduce latency and jitter， and to create Distributed Link Fragmentation and interleaving
B.use the service-policy command to attach a traffic flow to an interface on the router
C.use the ip rsvp bandwidth command to set a strict upper limit on the bandwidth NBAR uses， and to guarantee admission of any flows
D.use the policy-map command to define one or more QoS policies （such as shaping， policing， and so on） to apply to traffic defined by a class map
E.use the random-detect dscp command to modify the default minimum and maximum thresholds for the DSCP value
F.use the class-map command to define one or more traffic classes by specifying the criteria by which traffic is classified

A.apply the clock rate 64000 command on both serial interfaces connected to the WAN link
B.apply the bandwidth 64 command on both serial interfaces connected to the WAN link
C.apply the frame-relay voice-bandwidth 64000 command to enable the QoS Call Admission Control feature on the serial link
D.apply the max-conn 64 command on a perial peer basis on both sides of the serial link
E.apply the ip bandwidth-percent eigrp 1 64 command on both sides of the serial link
F.apply the auto-cost reference-bandwidth 64 command on both sides of the serial link