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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. Voice samples are packed into the___ ___ of a UDP/RTP packet and thus the network header overhead would be __.
payload field - lower
G.723.1 speech or audio - 6.3 - 5.3
Serialization delay
ends - begin - background noise - signal-to-noise threshold
2. Propagation delay in conjuction with handeling delay can cause noticeable
tandem compression
speech degradation
40 - 20 - 8 - 12
echo tail - 25
3. 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
7 - compressed
PSQM - objective - computer
Handling delay - queuing delay
4. Is the variation of packet interarrival time.
VAD - bandwidth - 50
jitter
person - computer
Jitter - interarrival - packet-based
5. 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.
ends - begin - background noise - signal-to-noise threshold
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
continuous media - timing reconstruction
waveform codecs
6. Proxy server is not required in an __ based system
40 - 20 - 8 - 12
IP
concealment strategy
Echo
7. __ builds in some reliability to the connectionless __ protocol - enables reliability with out using the overhead of __ - what protocol send multiples of the same packet __
2 - G.723.1
Latency
G.729 - voice - 8
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
8. __ Kbps low-delay variation of CELP voice compression 16 kbps
G.728
queuing - unacceptable
RTP is Realtime Transport Protocol - delay sensitive
Jitter - interarrival - packet-based
9. To make audio and video work with RTP what do you need. 2 things
7 - compressed
sequence number and timestamp
Echo
purchase leased lines - purchase VPN and use access code - OR put voice on data network
10. Caused by the length a signal must travel via light in fiber or electrical impulse in copper-based networks.
Propagation delay
<1%
data part - RTP Control Protocol (RTCP).
PSQM - objective - computer
11. __is characterized as the amount of time it takes for speech to exit the speaker's mouth and reach the listener's ear.
Latency
CRTP
Jitter - interarrival - packet-based
amplitude - hangover
12. 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)
last packet - voice
sequence number and timestamp
queuing - unacceptable
RTP timestamps - jitter
13. How many times can a digital to analog conversion in my network and PSTN total network happen - __ speech is less robust conversion
groups payload - qos - combining
7 - compressed
tandom encoding
ITU-T - 150
14. Is the amount of time it takes to actually place a bit or byte onto an interface. Its influence on delay is relatively minimal.
VAD - bandwidth - 50
speech degradation
Serialization delay
tandem compression
15. 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
source codecs
RTP is Realtime Transport Protocol - delay sensitive
forward error correction (FEC)
7 - compressed
16. What do you use to compress RTP header to 2 or 4 bytes
sizing
CRTP
G.729 - voice - 8
amplitude - hangover
17. __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
IP - RTP - UDP
sizing
amplitude - hangover
PCM - speech - header - information
18. A __ can trick the human ear into perceiving a higher-quality voice - but a __ cannot be tricked.
Jitter - interarrival - packet-based
last packet - voice
person - computer
Latency
19. RTP consists of a __ __ and a control part the called __
PCM - speech - header - information
data part - RTP Control Protocol (RTCP).
ends - begin - background noise - signal-to-noise threshold
VAD - bandwidth - 50
20. __ is an _ measurement of voice quality and the __ measures the voice
PSQM - objective - computer
ends - begin - background noise - signal-to-noise threshold
source codecs
person - computer
21. 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)
continuous media - timing reconstruction
amplitude - hangover
Echo
iLBC
22. This adaptation of jitter buffer __ is effective in compensating for delays.
IP
data part - RTP Control Protocol (RTCP).
sizing
person - computer
23. Simplify the router - use H.323 gatekeeper or voice managers to avoid __ __
speech degradation
tandem compression
concealment strategy
2 - G.723.1
24. PCM and ADPCM are examples of __ __
waveform codecs
Serialization delay
MOS - subjective -1 - 5
last packet - voice
25. __ __ occurs when you have more than one compression/decompression cycle for each phone call and Voice degradation occurs
VAD - bandwidth - 50
<1%
RTP is Realtime Transport Protocol - delay sensitive
tandom encoding
26. __ 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
payload field - lower
echo cancelers - software - DSP
250 - 250 - 500
G.723.1 speech or audio - 6.3 - 5.3
27. __ __ conceals interarrival packet delay variation.
jitter buffer
QoS
IP/RTP/UDP - delay - quality - constrained
Latency
28. 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.
Handling delay - queuing delay
dial plan
queuing - unacceptable
waveform codecs
29. __ __ replays the last packet received
concealment strategy
G.728
data part - RTP Control Protocol (RTCP).
jitter buffer
30. RTP uses the __ __ to determine whether the packets are arriving in order - and it uses the __ __ information to determine the interarrival packet time (jitter).
purchase leased lines - purchase VPN and use access code - OR put voice on data network
compression - decompression
software - dynamic - RTP
sequence information - time-stamping
31. The difference between when the packet is expected and when it is actually received is __. - exists only in __ ___ networks
Latency
groups payload - qos - combining
Jitter - interarrival - packet-based
IP
32. You hear your own voice in the background ( 4wire)
purchase leased lines - purchase VPN and use access code - OR put voice on data network
Echo
40 - 20 - 8 - 12
IP/RTP/UDP - delay - quality - constrained
33. Bob@nextdoorneighbor.com is a __ entry but coverts then to an __ address
DNS - IP
<1%
2 - G.723.1
MOS - subjective -1 - 5
34. ___ ___ are used within Cisco IOS Software to determine what level of ___ - if any - exists within the network.
speech degradation
tandom encoding
RTP timestamps - jitter
payload field - lower
35. __ describes __ coding at __ - __ - __ and __ Kbps; you also can interchange ADPCM voice between packet voice and public phone or PBX networks
groups payload - qos - combining
begins - front-end speech clipping.
G.726 - ADPCM - 40 - 32 - 24 - 16
forward error correction (FEC)
36. PSQM was developed to 'hear' impairments caused by __ and __ and not packet loss or jitter
amplitude - hangover
G.711 PCM
compression - decompression
7 - compressed
37. What are 3 things you can do if they want to implement a corporate dial plan
purchase leased lines - purchase VPN and use access code - OR put voice on data network
7 - compressed
250 - 250 - 500
40 - 20 - 8 - 12
38. ___describes CELP compression that enables __ to be coded into _ Kbps streams;
G.729 - voice - 8
2 - G.723.1
DNS - IP
amplitude - hangover
39. Time of day of highest calls on circuit focus those on the __
Jitter - interarrival - packet-based
IP - RTP - UDP
busy house
data part - RTP Control Protocol (RTCP).
40. How do you fix queuing delay - you would add
software - dynamic - RTP
Latency
speech degradation
QoS
41. You stop Echo in a PSTN by __ __ and is done in __ which is located on each __
CRTP
echo cancelers - software - DSP
jitter
sequence information - time-stamping
42. When companies merge make sure you configure the __ __
40 - 20 - 8 - 12
dial plan
iLBC
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
43. Who scored highest in the MOS
G.711 PCM
concealment strategy
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
PSQM - objective - computer
44. VAD problems in determining when speech __ and __ - and in distinguishing speech from __ __. Its also known as __ __ __ __
ends - begin - background noise - signal-to-noise threshold
G.723.1 speech or audio - 6.3 - 5.3
groups payload - qos - combining
PCM - speech - header - information
45. If a packet is lost What is replayed? packet loss is common in data networks but not in __
250 - 250 - 500
last packet - voice
tandem compression
groups payload - qos - combining
46. 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
VAD - bandwidth - 50
G.726 - ADPCM - 40 - 32 - 24 - 16
jitter buffer
IP/RTP/UDP - delay - quality - constrained
47. 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).
payload field - lower
Echo
iLBC
source codecs
48. 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.
G.728
250 - 250 - 500
begins - front-end speech clipping.
G.711 PCM
49. Preferred codec for skype - PC to phone apps - A free speech codec suitable for robust voice communication over IP.
begins - front-end speech clipping.
iLBC
echo tail - 25
Latency
50. Using G.729 - just __ conversions from D/A cause the MOS score to decrease rapidly but __ is less resilient
RTP timestamps - jitter
Propagation delay
Echo
2 - G.723.1