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