Which two statements are true about the implementation of QoS? (Choose two)

Which two statements are true about the implementation of QoS? (Choose two)

A.
Implementing DiffServ involves the configuration of RSVP.

B.
Implementing IntServ allows QoS to be performed by configuring only the ingress and egress devices.

C.
Implementing IntServ involves the utilization of RSVP.

D.
Traffic should be classified and marked by the core network devices.

E.
Traffic should be classified and marked as close to the edge of the network as possible.