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