Domain.com is interested in deploying an IP telephony solution for their Domain.com facility and two remote test sites. The Domain.com facility has approximately 450 employees and will require a Cisco CallManager. Each of the test sites has 75 employees, and each test site will require a Cisco CallManager Express. Domain.com currently has an IP WAN connecting these sites. Which two of these services and signaling protocols need to be deployed on the IP WAN for this solution to function properly? (Choose two.)

A.
SIP call signaling protocol

B.
H.323 call signaling protocol

C.
MGCP call signaling protocol

D.
QoS services for call setup and RTP streams

E.
QoS services for RTP streams

F.
A SIP proxy to support H.450.x protocols