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