Which of the following is not a benefit of VoIP?

A.
Cost

B.
Convergence

C.
Flexibility

D.
Security

Explanation:
D: Voice over Internet Protocol (VoIP) refers to transmission technologies that deliver voice communications over IP networks. IP telephony uses technologies that are similar
to TCP/IP, so its vulnerabilities are also similar. The voice system is vulnerable to application manipulation (such as toll fraud and blocking), unauthorized administrative access,
and poor implementation. In terms of the network and media, it is also vulnerable to denial of service attacks against the gateways and network resources. Eavesdropping is also
a concern, since data traffic is sent in the clear text unless it is encrypted.
A is incorrect because cost is a benefit of VoIP. Using VoIP means a company has to pay for and maintain only one network, instead of one network dedicated to data
transmission and another network dedicated to voice transmission. Telephony features such as conference calling, call forwarding, and automatic redial are free from opensource
VoIP implementations, while traditional telecommunications companies charge extra for them. And, finally, VoIP costs are lower because of the way they are billed. VoIP
calls are billed per megabyte, while regular telephone calls are billed by the minute. In general, it is cheaper to send data over the Internet for a given period of time than it is to
use the regular telephone for that same amount of time.
B is incorrect because convergence is a benefit of VoIP. Convergence refers to the merging of the traditional IP network with the traditional analog phone network. This is a
benefit because a company no longer has to pay for and maintain separate networks for data and voice. However, while convergence saves money and administration
overhead, certain security issues must be understood and dealt with.
C is incorrect because flexibility is a benefit of VoIP. The technology easily supports multiple telephone calls over a single Internet broadband connection without having to add
extra lines. It also offers location independence. All that is needed to obtain a WAN or MAN phone connection to a VoIP provider is an adequate Internet connection. VoIP can
also be integrated with other Internet services, such as video conversation, file exchange during a call, and audio conferencing.