Which of the following should be performed to increase the availability of IP telephony by prioritizing
traffic?

A.
Subnetting

B.
NAT

C.
Quality of service

D.
NAC

Explanation:
Quality of Service (QoS) facilitates the deployment of media-rich applications, such as video conferencing
and Internet Protocol (IP) telephony, without adversely affecting network throughput.
Incorrect Answers:
A: Subnetting is a dividing process used on networks to divide larger groups of hosts into smaller
collections.
B: NAT converts the IP addresses of internal systems found in the header of network packets into public
IP addresses.
D: The goals of NAC are to prevent/reduce zero-day attacks, enforce security policy throughout the
network, and use identities to perform access control.
https://technet.microsoft.com/en-us/library/cc959594.aspx
Stewart, James Michael, CompTIA Security+ Review Guide, Sybex, Indianapolis, 2014, pp. 39, 40