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