What makes the DiffServ model more scalable than the IntServ model? (Choose all that apply.)

A.
DiffServ makes use of per-aggregate QoS instead of per-flow QoS.

B.
DiffServ makes use of hop-by-hop signaling which allows DiffServ to scale to a larger number of application flows.

C.
DiffServ is capable of implementing admission control either locally on the routers or be offloaded to a central policy server using the COPS protocol.

D.
DiffServ routers are not compelled to track the state information for each individual flow.

Explanation:
Incorrect:
B. No hop-by-hop signaling uses per-hop behavior
C. This is a feature of both models
Sources: Cisco IP QoS Introduction
http://www.cisco.com/en/US/tech/ CK5 43/ CK7 66/technologies_white_paper09186a00800a3e2f.shtml