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