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