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