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