Which statement best describes Call Admission Control?

A.
It extends QoS capabilities to protect voice from excessive data traffic.

B.
It protects voice from voice.

C.
It provides endpoint registration control.

D.
It provides endpoint bandwidth control.

Explanation:
Explanation
CAC should be used to keep excess voice traffic from the network by ensuring that there is enough bandwidth for new calls. Call admission control (CAC) is used to control the number of calls to reduce the WAN bandwidth for a site that has IPT. CAC is configured for the site on the CUCM servers. A maximum bandwidth or maximum number of calls is provisioned for the site. CAC enforces a maximum number of calls between two locations to ensure that call quality will not be degraded by allowing more calls than a network can support. CAC causes excessive calls between two locations to be refused. The IPT system must then either reroute the call to different available path, such as the PSTN, or deny the call.

Cisco Press CCDA 640-864 Official Certification Guide Fourth Edition, Chapter 14