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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. A __ can trick the human ear into perceiving a higher-quality voice - but a __ cannot be tricked.
amplitude - hangover
Jitter - interarrival - packet-based
IP - RTP - UDP
person - computer
2. __ __ conceals interarrival packet delay variation.
dial plan
sequence information - time-stamping
jitter buffer
DNS - IP
3. 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.728
sequence information - time-stamping
continuous media - timing reconstruction
G.711 PCM
4. Time of day of highest calls on circuit focus those on the __
Echo
IP - RTP - UDP
RTP timestamps - jitter
busy house
5. 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
echo tail - 25
<1%
DNS - IP
continuous media - timing reconstruction
6. Is the amount of time it takes to actually place a bit or byte onto an interface. Its influence on delay is relatively minimal.
ITU-T - 150
purchase leased lines - purchase VPN and use access code - OR put voice on data network
MOS - subjective -1 - 5
Serialization delay
7. VAD problems in determining when speech __ and __ - and in distinguishing speech from __ __. Its also known as __ __ __ __
dial plan
concealment strategy
250 - 250 - 500
ends - begin - background noise - signal-to-noise threshold
8. 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.
purchase leased lines - purchase VPN and use access code - OR put voice on data network
7 - compressed
VAD - bandwidth - 50
250 - 250 - 500
9. The jitter buffer found within Cisco IOS ___ is considered a __ queue. This queue can grow or shrink exponentially depending on the interarrival time of the __ packets.
IP
software - dynamic - RTP
sequence number and timestamp
G.726 - ADPCM - 40 - 32 - 24 - 16
10. VAD detects a drop-off of speech ___ - it waits a fixed amount of time before it stops putting speech frames in packets. This fixed amount of time is known as __ ( when the person stops talking)
Propagation delay
amplitude - hangover
software - dynamic - RTP
payload field - lower
11. 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.
Serialization delay
2 - G.723.1
IP/RTP/UDP - delay - quality - constrained
begins - front-end speech clipping.
12. Bob@nextdoorneighbor.com is a __ entry but coverts then to an __ address
DNS - IP
waveform codecs
Echo
G.723.1 speech or audio - 6.3 - 5.3
13. On a voip link What is the max packet loss
jitter
Propagation delay
continuous media - timing reconstruction
<1%
14. This adaptation of jitter buffer __ is effective in compensating for delays.
DNS - IP
sizing
payload field - lower
Echo
15. __ is not wasting __ when there is no sound to transmit. At least __ % is wasted
jitter buffer
sequence number and timestamp
VAD - bandwidth - 50
last packet - voice
16. RTP consists of a __ __ and a control part the called __
source codecs
continuous media - timing reconstruction
data part - RTP Control Protocol (RTCP).
Propagation delay
17. Caused by the length a signal must travel via light in fiber or electrical impulse in copper-based networks.
tandom encoding
QoS
Echo
Propagation delay
18. 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)
concealment strategy
RTP timestamps - jitter
begins - front-end speech clipping.
19. The difference between when the packet is expected and when it is actually received is __. - exists only in __ ___ networks
person - computer
sequence information - time-stamping
Echo
Jitter - interarrival - packet-based
20. __ is a __test given to listeners. The listeners give each sample of speech material a rating of __ (bad) to __ (excellent)
VAD - bandwidth - 50
MOS - subjective -1 - 5
ITU-T - 150
PCM - speech - header - information
21. If a packet is lost What is replayed? packet loss is common in data networks but not in __
forward error correction (FEC)
payload field - lower
continuous media - timing reconstruction
last packet - voice
22. To make audio and video work with RTP what do you need. 2 things
VAD - bandwidth - 50
sequence number and timestamp
MOS - subjective -1 - 5
G.711 - PCM - PSTN or PBX(voip networks)
23. __ recommends no more than __ms delay one-way transmission
software - dynamic - RTP
last packet - voice
ITU-T - 150
person - computer
24. How do you fix queuing delay - you would add
QoS
sequence information - time-stamping
concealment strategy
data part - RTP Control Protocol (RTCP).
25. Preferred codec for skype - PC to phone apps - A free speech codec suitable for robust voice communication over IP.
iLBC
MOS - subjective -1 - 5
<1%
Echo
26. Voice samples are packed into the___ ___ of a UDP/RTP packet and thus the network header overhead would be __.
payload field - lower
iLBC
G.729 - voice - 8
<1%
27. Is the variation of packet interarrival time.
Jitter - interarrival - packet-based
busy house
250 - 250 - 500
jitter
28. __is characterized as the amount of time it takes for speech to exit the speaker's mouth and reach the listener's ear.
Latency
RTP is Realtime Transport Protocol - delay sensitive
forward error correction (FEC)
concealment strategy
29. __ Kbps low-delay variation of CELP voice compression 16 kbps
sequence number and timestamp
G.728
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
MOS - subjective -1 - 5
30. How many times can a digital to analog conversion in my network and PSTN total network happen - __ speech is less robust conversion
RTP is Realtime Transport Protocol - delay sensitive
ends - begin - background noise - signal-to-noise threshold
7 - compressed
echo cancelers - software - DSP
31. __ builds in some reliability to the connectionless __ protocol - enables reliability with out using the overhead of __ - what protocol send multiples of the same packet __
forward error correction (FEC)
continuous media - timing reconstruction
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
echo tail - 25
32. __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
concealment strategy
RTP is Realtime Transport Protocol - delay sensitive
PCM - speech - header - information
echo tail - 25
33. You hear your own voice in the background ( 4wire)
G.726 - ADPCM - 40 - 32 - 24 - 16
tandem compression
Echo
Latency
34. Proxy server is not required in an __ based system
echo cancelers - software - DSP
IP
G.729 - voice - 8
waveform codecs
35. Who scored highest in the MOS
queuing - unacceptable
ends - begin - background noise - signal-to-noise threshold
G.711 PCM
dial plan
36. Simplify the router - use H.323 gatekeeper or voice managers to avoid __ __
tandem compression
continuous media - timing reconstruction
amplitude - hangover
sequence information - time-stamping
37. __ __ occurs when you have more than one compression/decompression cycle for each phone call and Voice degradation occurs
dial plan
Jitter - interarrival - packet-based
groups payload - qos - combining
tandom encoding
38. 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).
compression - decompression
amplitude - hangover
source codecs
Jitter - interarrival - packet-based
39. RTP uses the __ __ to determine whether the packets are arriving in order - and it uses the __ __ information to determine the interarrival packet time (jitter).
ends - begin - background noise - signal-to-noise threshold
sequence information - time-stamping
last packet - voice
250 - 250 - 500
40. __ protocol that carries audio and video packets - is the standard for transmitting__ __traffic across packet-based networks
RTP is Realtime Transport Protocol - delay sensitive
Handling delay - queuing delay
groups payload - qos - combining
dial plan
41. Using G.729 - just __ conversions from D/A cause the MOS score to decrease rapidly but __ is less resilient
250 - 250 - 500
CRTP
2 - G.723.1
payload field - lower
42. __ describes __ coding at __ - __ - __ and __ Kbps; you also can interchange ADPCM voice between packet voice and public phone or PBX networks
software - dynamic - RTP
CRTP
G.726 - ADPCM - 40 - 32 - 24 - 16
payload field - lower
43. __ is an _ measurement of voice quality and the __ measures the voice
last packet - voice
sequence number and timestamp
IP - RTP - UDP
PSQM - objective - computer
44. You stop Echo in a PSTN by __ __ and is done in __ which is located on each __
IP
echo cancelers - software - DSP
Propagation delay
continuous media - timing reconstruction
45. __ the 64 Kbps __ voice coding technique - This is used for the digital voice delivery in the __ or __
G.711 - PCM - PSTN or PBX(voip networks)
jitter buffer
echo cancelers - software - DSP
7 - compressed
46. __ 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
Latency
7 - compressed
G.723.1 speech or audio - 6.3 - 5.3
IP - RTP - UDP
47. In an unmanaged - congested network - ___delay can add up to two seconds of delay (or result in the packet being dropped). This lengthy period of delay is___ in almost any voice network. delay)
QoS
IP/RTP/UDP - delay - quality - constrained
IP - RTP - UDP
queuing - unacceptable
48. ___ ___ are used within Cisco IOS Software to determine what level of ___ - if any - exists within the network.
dial plan
echo tail - 25
QoS
RTP timestamps - jitter
49. Propagation delay in conjuction with handeling delay can cause noticeable
CRTP
speech degradation
software - dynamic - RTP
2 - G.723.1
50. What are 3 things you can do if they want to implement a corporate dial plan
echo cancelers - software - DSP
purchase leased lines - purchase VPN and use access code - OR put voice on data network
QoS
source codecs