Quality of Service (QoS)

A user reports that VoIP telephone calls have static and a noticeable delay whenever other users are using the home network. Which of the following routing features should be used on the home network to resolve this issue?
a.
QoS
b.
NAT
c.
Port forwarding
d.
Port triggering

Ans. A.
http://en.wikipedia.org/wiki/Quality_of_service
The quality of service (QoS) refers to several related aspects of telephony and computer networks that allow the transport of traffic with special requirements. In particular, much technology has been developed to allow computer networks to become as useful as telephone network for audio conversations, as well as supporting new applications with even more strict service demands.

Answer is not b. 

Network address translation

In computer networking, network address translation (NAT) is the process of modifying IP address information in IP packet headers while in transit across a traffic routing device.

http://en.wikipedia.org/wiki/Network_address_translation