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