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Test your basic knowledge |
CCNA Voice - 3
Start Test
Study First
Subjects
:
cisco
,
it-skills
,
ccna
Instructions:
Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can
study here
.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.
This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. How many times can a digital to analog conversion in my network and PSTN total network happen - __ speech is less robust conversion
echo tail - 25
7 - compressed
VAD - bandwidth - 50
IP - RTP - UDP
2. VAD problems in determining when speech __ and __ - and in distinguishing speech from __ __. Its also known as __ __ __ __
QoS
ends - begin - background noise - signal-to-noise threshold
IP/RTP/UDP - delay - quality - constrained
G.711 PCM
3. __ recommends no more than __ms delay one-way transmission
jitter buffer
speech degradation
ITU-T - 150
person - computer
4. The difference between when the packet is expected and when it is actually received is __. - exists only in __ ___ networks
Handling delay - queuing delay
7 - compressed
Jitter - interarrival - packet-based
jitter
5. Who scored highest in the MOS
40 - 20 - 8 - 12
source codecs
software - dynamic - RTP
G.711 PCM
6. __ builds in some reliability to the connectionless __ protocol - enables reliability with out using the overhead of __ - what protocol send multiples of the same packet __
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
QoS
40 - 20 - 8 - 12
queuing - unacceptable
7. __ is a __test given to listeners. The listeners give each sample of speech material a rating of __ (bad) to __ (excellent)
MOS - subjective -1 - 5
Handling delay - queuing delay
sequence number and timestamp
echo tail - 25
8. __ protocol that carries audio and video packets - is the standard for transmitting__ __traffic across packet-based networks
sequence information - time-stamping
data part - RTP Control Protocol (RTCP).
jitter buffer
RTP is Realtime Transport Protocol - delay sensitive
9. To reduce the overall ___ overhead introduced by the 54-byte header - multiple voice samples can be packed into a single Ethernet frame to transmit. Although this can increase the voice ___ - increasing this count can improve the overall voice___ - e
ends - begin - background noise - signal-to-noise threshold
IP/RTP/UDP - delay - quality - constrained
ITU-T - 150
PCM - speech - header - information
10. __ __ occurs when you have more than one compression/decompression cycle for each phone call and Voice degradation occurs
G.711 - PCM - PSTN or PBX(voip networks)
dial plan
tandom encoding
VAD - bandwidth - 50
11. __ is an _ measurement of voice quality and the __ measures the voice
40 - 20 - 8 - 12
sequence information - time-stamping
amplitude - hangover
PSQM - objective - computer
12. Proxy server is not required in an __ based system
40 - 20 - 8 - 12
PSQM - objective - computer
IP
tandem compression
13. Is the amount of time it takes to actually place a bit or byte onto an interface. Its influence on delay is relatively minimal.
IP - RTP - UDP
250 - 250 - 500
40 - 20 - 8 - 12
Serialization delay
14. These techniques can be grouped together generally as __ __ and include variations such as linear predictive coding (LPC) - code excited linear prediction compression (CELP) - and multipulse - multilevel quantization (MP-MLQ).
sequence number and timestamp
amplitude - hangover
source codecs
7 - compressed
15. You hear your own voice in the background ( 4wire)
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
jitter
Echo
PSQM - objective - computer
16. ___describes CELP compression that enables __ to be coded into _ Kbps streams;
G.729 - voice - 8
IP/RTP/UDP - delay - quality - constrained
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
G.723.1 speech or audio - 6.3 - 5.3
17. What are 3 things you can do if they want to implement a corporate dial plan
G.711 PCM
purchase leased lines - purchase VPN and use access code - OR put voice on data network
speech degradation
QoS
18. __ Describes a compression technique that you can use to compress ___or other __ signal components of multimedia service at a low bit rate - MP-MLQ provides greater quality at __ Kbps - CELP provides flexibility at __Kbps
PSQM - objective - computer
Echo
busy house
G.723.1 speech or audio - 6.3 - 5.3
19. __ Kbps low-delay variation of CELP voice compression 16 kbps
ends - begin - background noise - signal-to-noise threshold
busy house
G.728
echo cancelers - software - DSP
20. Echo cancellers are limited by the total amount of time they wait for the reflected speech to be received __ __. A good time to configure is __ms
Serialization delay
person - computer
250 - 250 - 500
echo tail - 25
21. __ __ conceals interarrival packet delay variation.
QoS
jitter buffer
waveform codecs
person - computer
22. Defines many different causes of delay (actual packetization - compression - and packet switching) and is caused by devices that forward the frame through the network. Includes __ ___ for congested networks.
busy house
G.723.1 speech or audio - 6.3 - 5.3
Handling delay - queuing delay
VAD - bandwidth - 50
23. ___ ___ are used within Cisco IOS Software to determine what level of ___ - if any - exists within the network.
MOS - subjective -1 - 5
Jitter - interarrival - packet-based
RTP is Realtime Transport Protocol - delay sensitive
RTP timestamps - jitter
24. Caused by the length a signal must travel via light in fiber or electrical impulse in copper-based networks.
Propagation delay
PSQM - objective - computer
<1%
Jitter - interarrival - packet-based
25. RTP uses the __ __ to determine whether the packets are arriving in order - and it uses the __ __ information to determine the interarrival packet time (jitter).
IP - RTP - UDP
begins - front-end speech clipping.
QoS
sequence information - time-stamping
26. How does G.729 header go __/__/__
IP
G.711 - PCM - PSTN or PBX(voip networks)
RTP timestamps - jitter
IP - RTP - UDP
27. Voice samples are packed into the___ ___ of a UDP/RTP packet and thus the network header overhead would be __.
echo tail - 25
waveform codecs
payload field - lower
<1%
28. On a voip link What is the max packet loss
jitter
person - computer
250 - 250 - 500
<1%
29. How do you fix queuing delay - you would add
forward error correction (FEC)
dial plan
QoS
2 - G.723.1
30. Time of day of highest calls on circuit focus those on the __
PCM - speech - header - information
40 - 20 - 8 - 12
busy house
Echo
31. __is characterized as the amount of time it takes for speech to exit the speaker's mouth and reach the listener's ear.
PCM - speech - header - information
G.728
software - dynamic - RTP
Latency
32. Customers that have almost unlimited bandwidth - however - consider __ a worthwhile mechanism to enhance reliability and voice quality - mechanism makes it more probable that one of the packets will make the journey from sender to receiver
forward error correction (FEC)
250 - 250 - 500
Latency
last packet - voice
33. Satellite transmission takes approximately __ ms for a transmission to reach the satellite and another __ ms for it to come back down to Earth. This results in a total delay of __ ms.
QoS
250 - 250 - 500
payload field - lower
RTP timestamps - jitter
34. What do you use to compress RTP header to 2 or 4 bytes
amplitude - hangover
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
VAD - bandwidth - 50
CRTP
35. When companies merge make sure you configure the __ __
sequence number and timestamp
250 - 250 - 500
dial plan
Latency
36. You stop Echo in a PSTN by __ __ and is done in __ which is located on each __
G.729 - voice - 8
G.728
<1%
echo cancelers - software - DSP
37. The problem with VAD is detecting when speech __. This is known as__ Usually - the person listening to the speech does not notice this cut off because it did not record and transmit any codec.
amplitude - hangover
source codecs
begins - front-end speech clipping.
concealment strategy
38. __ __ replays the last packet received
software - dynamic - RTP
concealment strategy
Handling delay - queuing delay
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
39. The data part of RTP is a thin protocol that provides support for applications with real-time properties - such as __ __ (for example - audio and video) - including __ __ - loss detection - and content identification.
G.726 - ADPCM - 40 - 32 - 24 - 16
Echo
iLBC
continuous media - timing reconstruction
40. Propagation delay in conjuction with handeling delay can cause noticeable
Latency
PSQM - objective - computer
speech degradation
RTP is Realtime Transport Protocol - delay sensitive
41. __by default - sends two 10-ms G.729 speech frames in every packet - If you send more __ frames you put in a packet the fewer ___ you require but if you loose a packet the more __ you lose
purchase leased lines - purchase VPN and use access code - OR put voice on data network
ITU-T - 150
PCM - speech - header - information
jitter buffer
42. It has a large header of __ bytes - Size of headers IP/RTP/UDP
G.711 PCM
40 - 20 - 8 - 12
PCM - speech - header - information
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
43. A __ can trick the human ear into perceiving a higher-quality voice - but a __ cannot be tricked.
payload field - lower
IP
person - computer
dial plan
44. This adaptation of jitter buffer __ is effective in compensating for delays.
sizing
busy house
payload field - lower
dial plan
45. Is the variation of packet interarrival time.
G.726 - ADPCM - 40 - 32 - 24 - 16
jitter
IP/RTP/UDP - delay - quality - constrained
40 - 20 - 8 - 12
46. PCM and ADPCM are examples of __ __
Serialization delay
G.711 - PCM - PSTN or PBX(voip networks)
waveform codecs
jitter buffer
47. Simplify the router - use H.323 gatekeeper or voice managers to avoid __ __
40 - 20 - 8 - 12
250 - 250 - 500
tandem compression
QoS
48. __ is not wasting __ when there is no sound to transmit. At least __ % is wasted
begins - front-end speech clipping.
echo cancelers - software - DSP
continuous media - timing reconstruction
VAD - bandwidth - 50
49. RTP consists of a __ __ and a control part the called __
data part - RTP Control Protocol (RTCP).
IP/RTP/UDP - delay - quality - constrained
busy house
begins - front-end speech clipping.
50. __ describes __ coding at __ - __ - __ and __ Kbps; you also can interchange ADPCM voice between packet voice and public phone or PBX networks
G.726 - ADPCM - 40 - 32 - 24 - 16
echo tail - 25
PSQM - objective - computer
compression - decompression