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