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