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