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