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