» VoIP Design Elements

By | September 24, 2012

Here you will find answers to CVoice – VoIP Design Element Questions

Question 1

Refer to the exhibit.


Lighthorse Equine Management would like to investigate converging voice and data on their existing T1 Frame Relay WAN link between New York and Atlanta. Currently the following list of applications are consuming no more bandwidth than what is listed on this segment of the network.

T1 link 1536 kbps
e-mail 75 kbps
internet 200 kbps
Oracle 500 kbps
FTP 250 kbps
Total 1025 kbps

The customer has allocated 25% of the WAN link for routing updates and other overhead. They would like to increase the number of samples encapsulated in each PDU to 40 ms. You have calculated 6 bytes of overhead for Frame Relay, no cRTP, and the use of the G.711 codec. How many simultaneous calls could be placed on this link?

A. 0 calls
B. 1 call
C. 2 calls
D. no more than 5 calls
E. no more than 10 calls
F. no more than 20 calls

Answer: B

Question 2

Refer to the exhibit. A QoS strategy has already been deployed on the LAN. Choose three WAN QoS best practices that should be used over the WAN link. (Choose three.)


A. Implement NBAR.
B. Implement admission control.
C. Mark voice traffic as EF in DSCP.
D. Mark voice traffic highest priority in 802.1p.
E. Use cRTP to maximize bandwidth utilization.
F. Configure access switches to trust traffic from IP phones.

Answer: B C E

Question 3

Refer to the exhibit. Users are not able to complete a call from 678-555-1212 to 770-555-1111. What is the correct diagnosis for the problem?


A. incorrect destination-pattern in router 1
B. incorrect POTS dial-peer statement in router 2
C. incorrect session-target statement in router 2
D. incorrect port statement in router 1 pots dial peer
E. missing no digit-strip on the voip dial peer in router 1

Answer: A

Question 4

A telemarketing firm needs to use number translation for incoming and outgoing calls. They have defined two translation profiles, one for incoming and one for outgoing calls. What can be used to simplify this task?

A. dial peer
B. voice port
C. hunt group
D. trunk group
E. source IP group

Answer: D

Question 5

Which command parameter specifies that the router should not attempt to initiate a trunk connection but should wait for an incoming call before establishing the trunk?

A. codec clear-channel
B. connection-trunk 404555…. answer-mode
C. voice-port 1/0:1
D. ds0-group timeslots 1-23 type ext-sig

Answer: B

Question 6

In a VoIP environment when speech samples are framed every 20 ms, a payload of 20 bytes is generated. Assuming a total packet length of 60 bytes, what is the length of the packet header if cRTP is deployed without redundancy checks?

A. 1 byte
B. 2 bytes
C. 3 bytes
D. 4 bytes
E. 20 bytes
F. 40 bytes

Answer: B

Question 7

You have set up a complex dial plan using translation rules. The following translation rule has been configured. What output would correspond to the test translation-rule command?

translation-rule 1
rule 0 ^0.. 215550210
rule 1 ^1.. 215550211
rule 2 ^2.. 215550212
rule 3 ^3.. 215550213
rule 4 ^4.. 215550214
rule 5 ^5.. 215550215
rule 6 ^6.. 215550216
rule 7 ^7.. 215550217
rule 8 ^8.. 215550218
rule 9 ^9.. 215550210

A. test translation-rule 1 512
The replaced number: 21555021512
B. test translation-rule 1 555
The replaced number: 55521555021
C. test translation-rule 1 617
The replaced number: 61721555021
D. test translation-rule 1 910
The replaced number: 21555021910

Answer: A

Question 8

Which device is used to allow an H.323 stream to transit a firewall?

A. gatekeeper
B. gateway
C. proxy

Answer: C

Question 9

To hide its identity when initiating calls, Phone B requests that Server B place its calls for it. What kind of device is Server B?


A. proxy
B. redirect
C. registrar
D. user agent client
E. user agent server

Answer: A