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