What are the two differences between the IntServe and DiffServ models of QoS? (Choose two.)

A.
DiffServ provides absolute QoS guarantees.

B.
IntServ is the default QoS mechanism for all routers, because applications signal the router with
the QoS level they require.

C.
DiffServ inherits the connection-oriented approach from telephony network design. Every
individual communication must explicitly specify its traffic descriptor and requested resources to
the network.

D.
With IntServ, packet delivery is guaranteed. However, the use of IntServ can severely limit the
scalability of a network.

E.
DiffServ was designed to overcome the limitations of both the best-effort and IntServ models
and can provide an “almost guaranteed” QoS.

Explanation: