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