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