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