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