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