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