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