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