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