CCNA Voice Practice Tests – Cisco network to support VoIP (11-15)

Topic 5 – Describe and configure a Cisco network to support VoIP

Question 11
Which option cannot be configured using Cisco Configuration Assistant?
A.voice VLAN only
B.voice and data VLANs
C.script selection for the AutoAttendant
D.SIP trunk to an ITSP
Answer: A
This question tests the CCA configuration.
Cisco Configuration Assistant simplifies the task of configuring, deploying, and administering the Cisco Smart Business Communications System and it improves network security and performance and substantially reduces deployment and configuration time. The voice VLAN settings should only be modified by CCA using the Configure > Telephony > Voice > Network tab.

Question 12
A telephone numbering plan is a plan for allocating telephone number ranges to countries, regions, areas and exchanges and to non-fixed telephone networks such as mobile phone networks. Dial plans should not be confused with numbering plans. A closed numbering plan, such as found in North America, features fixed length area codes and local numbers. An open numbering plan, as found in assorted countries that have not yet standardized, features variance in length of area code or local number, or both. The rules for dialing the numbers assigned by the numbering plan vary by defining which digits need not always be dialed (codes) and digits that must always be dialed (local number). What is a numbering plan?
A.numbering plan defines the path from one endpoint to another
B.numbering plan defines the calling privileges of an endpoint
C.numbering plan defines how digits are manipulated in processing a call.
D.numbering plan defines the endpoint addressing used in a voice system
Answer: D
A numbering plan describes the endpoint addressing scheme used in a VoIP network and is analogous to the IP addressing scheme used in an IP network. A numbering plan identifies each VoIP endpoint and application in the network with a unique telephone number. A well-designed numbering plan should evaluate both current requirements and potential growth requirements to avoid the need to renumber as more users connect to the voice network.

Question 13
According to the G.114 recommendation, the maximum one-way delay for voice should ideally not exceed how much delay?
A.100 ms
B.150 ms
C.200 ms
D.250 ms
Answer: B
ITU-T recommended that one-way end-to-end delay be held to 150ms or less for a voice connection. Delay up to 400ms can be tolerated depending on user expectations. It might be unreasonable on a short call, but a user might find it acceptable on an intercontinental call to a remote area.

Question 14
Identify the preferred voice quality measurement approach for VoIP networks.
Answer: B
This question is to examine the voice quality measurement approach.
PESQ (Perceptual Evaluation of Speech Quality) is a family of standards comprising a test methodology for automated assessment of the speech quality as experienced by a user of a telephony system. The ultimate advantage of it is that the data are concluded from multi-environment, including noise environment, noiseless environment, etc. PESQ is a worldwide applied industry standard for objective voice quality testing used by phone manufacturers, network equipment vendors and telecom operators. Choose B.

Question 15
Identify three quality issues that can result because of a lack of network bandwidth.
(Choose 3.)
D.Packet loss
Answer: A C D
If there is a lack of network bandwidth, these problems will occur, Jitter, Delay, and Packet loss. Delay and jitter can degrade the voice application to the point of being unacceptable to the average user. Delay is the time taken from point-to-point in a network. Delay can be measured in either one-way or round-trip delay. Jitter is the variation in delay over time from point-to-point. Packet loss is losing packets along the data path, which severely degrades the voice application.