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