A. On congested links， all forms of traffic will require some form of QoS.
B. All traffic types and requirements should be examined to determine the number of traffic classes required.
C. In the implementation of link efficiency mechanisms on links that typically transport relatively large packets， header compression will be most efficient.
D. In the implementation of link efficiency mechanisms on links that typically transport relatively small packets， header compression will be most efficient.
E. In the implementation of link efficiency mechanisms on links that typically transport relatively small packets， payload compression will be most efficient.
F. Payload compression provides more available bandwidth and reduces processing delay time.

A. Because services are allocated throughout the network before the transmission of data begins， traffic classes can be guaranteed QoS services.
B. Traffic classes are marked with Layer 2 markings to allow for more granularity in identifying traffic classes.
C. Traffic classes are marked with Layer 3 markings to allow them to traverse different network types without loss of QoS information.
D. Traffic classes allow networks to provide proper QoS treatment of packets without applications having to request services.
E. Based upon the network capabilities， QoS markings are placed on packets as needed throughout the network to allow for proper QoS treatment of packets.
F. QoS markings are placed on packets as close to the network edge as possible to allow distribution and core devices to determine QoS actions as quickly as possible.