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