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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. 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
data part - RTP Control Protocol (RTCP).
VAD - bandwidth - 50
source codecs
IP/RTP/UDP - delay - quality - constrained
2. Is the variation of packet interarrival time.
IP/RTP/UDP - delay - quality - constrained
dial plan
G.711 - PCM - PSTN or PBX(voip networks)
jitter
3. 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.
CRTP
forward error correction (FEC)
jitter
begins - front-end speech clipping.
4. __ __ replays the last packet received
echo cancelers - software - DSP
7 - compressed
waveform codecs
concealment strategy
5. Proxy server is not required in an __ based system
IP - RTP - UDP
tandem compression
IP
echo tail - 25
6. 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
forward error correction (FEC)
tandom encoding
continuous media - timing reconstruction
G.728
7. 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.
Echo
continuous media - timing reconstruction
last packet - voice
G.711 PCM
8. If a packet is lost What is replayed? packet loss is common in data networks but not in __
dial plan
last packet - voice
data part - RTP Control Protocol (RTCP).
tandom encoding
9. PCM and ADPCM are examples of __ __
Latency
waveform codecs
forward error correction (FEC)
Serialization delay
10. The difference between when the packet is expected and when it is actually received is __. - exists only in __ ___ networks
Jitter - interarrival - packet-based
Latency
Echo
echo tail - 25
11. Propagation delay in conjuction with handeling delay can cause noticeable
jitter
speech degradation
2 - G.723.1
Echo
12. Time of day of highest calls on circuit focus those on the __
busy house
DNS - IP
2 - G.723.1
last packet - voice
13. 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
G.711 PCM
software - dynamic - RTP
250 - 250 - 500
14. ___describes CELP compression that enables __ to be coded into _ Kbps streams;
2 - G.723.1
sequence number and timestamp
QoS
G.729 - voice - 8
15. What do you use to compress RTP header to 2 or 4 bytes
speech degradation
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
continuous media - timing reconstruction
CRTP
16. 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)
sequence number and timestamp
amplitude - hangover
MOS - subjective -1 - 5
G.726 - ADPCM - 40 - 32 - 24 - 16
17. Using G.729 - just __ conversions from D/A cause the MOS score to decrease rapidly but __ is less resilient
MOS - subjective -1 - 5
Jitter - interarrival - packet-based
G.711 - PCM - PSTN or PBX(voip networks)
2 - G.723.1
18. How many times can a digital to analog conversion in my network and PSTN total network happen - __ speech is less robust conversion
7 - compressed
last packet - voice
iLBC
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
19. PSQM was developed to 'hear' impairments caused by __ and __ and not packet loss or jitter
Serialization delay
compression - decompression
forward error correction (FEC)
busy house
20. 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.
Jitter - interarrival - packet-based
sequence information - time-stamping
2 - G.723.1
Handling delay - queuing delay
21. __ recommends no more than __ms delay one-way transmission
dial plan
ITU-T - 150
G.728
IP
22. You stop Echo in a PSTN by __ __ and is done in __ which is located on each __
tandem compression
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
echo cancelers - software - DSP
begins - front-end speech clipping.
23. RTP consists of a __ __ and a control part the called __
software - dynamic - RTP
data part - RTP Control Protocol (RTCP).
iLBC
sequence information - time-stamping
24. This adaptation of jitter buffer __ is effective in compensating for delays.
iLBC
G.729 - voice - 8
CRTP
sizing
25. Who scored highest in the MOS
groups payload - qos - combining
payload field - lower
concealment strategy
G.711 PCM
26. RTCP provides support for real-time conferencing of __ of any size within an Internet - does not send __ - offers __and supports __ media streams
RTP timestamps - jitter
compression - decompression
groups payload - qos - combining
amplitude - hangover
27. __ __ conceals interarrival packet delay variation.
waveform codecs
jitter buffer
RTP timestamps - jitter
last packet - voice
28. 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.
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
forward error correction (FEC)
G.729 - voice - 8
software - dynamic - RTP
29. ___ ___ are used within Cisco IOS Software to determine what level of ___ - if any - exists within the network.
tandem compression
waveform codecs
RTP timestamps - jitter
person - computer
30. __ the 64 Kbps __ voice coding technique - This is used for the digital voice delivery in the __ or __
MOS - subjective -1 - 5
dial plan
source codecs
G.711 - PCM - PSTN or PBX(voip networks)
31. Bob@nextdoorneighbor.com is a __ entry but coverts then to an __ address
tandem compression
G.728
IP - RTP - UDP
DNS - IP
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
begins - front-end speech clipping.
amplitude - hangover
<1%
33. 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
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
begins - front-end speech clipping.
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.
software - dynamic - RTP
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
concealment strategy
dial plan
35. RTP uses the __ __ to determine whether the packets are arriving in order - and it uses the __ __ information to determine the interarrival packet time (jitter).
sizing
iLBC
last packet - voice
sequence information - time-stamping
36. VAD problems in determining when speech __ and __ - and in distinguishing speech from __ __. Its also known as __ __ __ __
tandom encoding
person - computer
busy house
ends - begin - background noise - signal-to-noise threshold
37. When companies merge make sure you configure the __ __
G.728
2 - G.723.1
dial plan
person - computer
38. How do you fix queuing delay - you would add
QoS
data part - RTP Control Protocol (RTCP).
tandom encoding
IP/RTP/UDP - delay - quality - constrained
39. __ builds in some reliability to the connectionless __ protocol - enables reliability with out using the overhead of __ - what protocol send multiples of the same packet __
sizing
MOS - subjective -1 - 5
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
ITU-T - 150
40. 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)
forward error correction (FEC)
ITU-T - 150
groups payload - qos - combining
queuing - unacceptable
41. __ __ occurs when you have more than one compression/decompression cycle for each phone call and Voice degradation occurs
person - computer
speech degradation
7 - compressed
tandom encoding
42. __ describes __ coding at __ - __ - __ and __ Kbps; you also can interchange ADPCM voice between packet voice and public phone or PBX networks
ITU-T - 150
G.711 PCM
source codecs
G.726 - ADPCM - 40 - 32 - 24 - 16
43. How does G.729 header go __/__/__
echo tail - 25
G.723.1 speech or audio - 6.3 - 5.3
IP - RTP - UDP
G.729 - voice - 8
44. __is characterized as the amount of time it takes for speech to exit the speaker's mouth and reach the listener's ear.
Handling delay - queuing delay
Latency
G.728
software - dynamic - RTP
45. __ 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
software - dynamic - RTP
sequence information - time-stamping
G.723.1 speech or audio - 6.3 - 5.3
VAD - bandwidth - 50
46. To make audio and video work with RTP what do you need. 2 things
sizing
Latency
sequence number and timestamp
ITU-T - 150
47. __ is not wasting __ when there is no sound to transmit. At least __ % is wasted
data part - RTP Control Protocol (RTCP).
amplitude - hangover
Latency
VAD - bandwidth - 50
48. Simplify the router - use H.323 gatekeeper or voice managers to avoid __ __
speech degradation
Serialization delay
QoS
tandem compression
49. __ is a __test given to listeners. The listeners give each sample of speech material a rating of __ (bad) to __ (excellent)
groups payload - qos - combining
MOS - subjective -1 - 5
source codecs
sequence information - time-stamping
50. Preferred codec for skype - PC to phone apps - A free speech codec suitable for robust voice communication over IP.
echo cancelers - software - DSP
<1%
iLBC
QoS