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