What are two key advantages of the DiffServ model? (Choose two.)

A.
It is highly scalable

B.
It provides many possible levels of service

C.
It provides completely guaranteed quality of service

D.
It works seamlessly with very little network configuration

E.
It reserves bandwidth explicitly for each level of service

Explanation:

The Differentiated Services (DiffServ) model describes services associated with traffic classes. Traffic classes are identified by the value of the DiffServ Code Point (DSCP replaces IP precedence in the ToS field of the IP header). The main goal of the DiffServ model are to provide scalability and a similar level of QoS to the Int Serv model, without having to do it on a per-flow basis. The network simply identifies a class (not application) and applies the appropriate per-hop behavior (QoS mechanism)
Reference: Introduction to IP QoS (Course) p.34