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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. Voice samples are packed into the___ ___ of a UDP/RTP packet and thus the network header overhead would be __.
payload field - lower
amplitude - hangover
sequence information - time-stamping
Latency
2. __ is an _ measurement of voice quality and the __ measures the voice
PCM - speech - header - information
RTP timestamps - jitter
PSQM - objective - computer
G.723.1 speech or audio - 6.3 - 5.3
3. You hear your own voice in the background ( 4wire)
speech degradation
data part - RTP Control Protocol (RTCP).
G.711 - PCM - PSTN or PBX(voip networks)
Echo
4. Bob@nextdoorneighbor.com is a __ entry but coverts then to an __ address
DNS - IP
CRTP
source codecs
ITU-T - 150
5. __ Kbps low-delay variation of CELP voice compression 16 kbps
G.728
sequence information - time-stamping
sizing
ends - begin - background noise - signal-to-noise threshold
6. You stop Echo in a PSTN by __ __ and is done in __ which is located on each __
G.711 - PCM - PSTN or PBX(voip networks)
G.723.1 speech or audio - 6.3 - 5.3
echo cancelers - software - DSP
person - computer
7. ___ ___ are used within Cisco IOS Software to determine what level of ___ - if any - exists within the network.
RTP timestamps - jitter
PSQM - objective - computer
concealment strategy
40 - 20 - 8 - 12
8. 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.
iLBC
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
concealment strategy
jitter
9. What are 3 things you can do if they want to implement a corporate dial plan
dial plan
iLBC
purchase leased lines - purchase VPN and use access code - OR put voice on data network
concealment strategy
10. 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)
compression - decompression
sequence number and timestamp
queuing - unacceptable
purchase leased lines - purchase VPN and use access code - OR put voice on data network
11. __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.728
queuing - unacceptable
PCM - speech - header - information
groups payload - qos - combining
12. Is the amount of time it takes to actually place a bit or byte onto an interface. Its influence on delay is relatively minimal.
Echo
sequence number and timestamp
ends - begin - background noise - signal-to-noise threshold
Serialization delay
13. Caused by the length a signal must travel via light in fiber or electrical impulse in copper-based networks.
groups payload - qos - combining
Propagation delay
waveform codecs
continuous media - timing reconstruction
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).
Serialization delay
continuous media - timing reconstruction
G.726 - ADPCM - 40 - 32 - 24 - 16
sequence information - time-stamping
15. 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
data part - RTP Control Protocol (RTCP).
echo tail - 25
G.726 - ADPCM - 40 - 32 - 24 - 16
concealment strategy
16. Is the variation of packet interarrival time.
MOS - subjective -1 - 5
jitter
Latency
CRTP
17. VAD problems in determining when speech __ and __ - and in distinguishing speech from __ __. Its also known as __ __ __ __
ends - begin - background noise - signal-to-noise threshold
continuous media - timing reconstruction
G.711 - PCM - PSTN or PBX(voip networks)
RTP is Realtime Transport Protocol - delay sensitive
18. __ 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
concealment strategy
G.723.1 speech or audio - 6.3 - 5.3
amplitude - hangover
PCM - speech - header - information
19. __ is a __test given to listeners. The listeners give each sample of speech material a rating of __ (bad) to __ (excellent)
waveform codecs
ends - begin - background noise - signal-to-noise threshold
MOS - subjective -1 - 5
iLBC
20. RTP consists of a __ __ and a control part the called __
Handling delay - queuing delay
data part - RTP Control Protocol (RTCP).
source codecs
ends - begin - background noise - signal-to-noise threshold
21. A __ can trick the human ear into perceiving a higher-quality voice - but a __ cannot be tricked.
RTP is Realtime Transport Protocol - delay sensitive
Serialization delay
data part - RTP Control Protocol (RTCP).
person - computer
22. 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)
7 - compressed
payload field - lower
G.723.1 speech or audio - 6.3 - 5.3
amplitude - hangover
23. 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.
waveform codecs
RTP is Realtime Transport Protocol - delay sensitive
ITU-T - 150
24. __ the 64 Kbps __ voice coding technique - This is used for the digital voice delivery in the __ or __
G.711 - PCM - PSTN or PBX(voip networks)
iLBC
G.723.1 speech or audio - 6.3 - 5.3
compression - decompression
25. PSQM was developed to 'hear' impairments caused by __ and __ and not packet loss or jitter
purchase leased lines - purchase VPN and use access code - OR put voice on data network
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
Latency
compression - decompression
26. PCM and ADPCM are examples of __ __
amplitude - hangover
begins - front-end speech clipping.
source codecs
waveform codecs
27. RTCP provides support for real-time conferencing of __ of any size within an Internet - does not send __ - offers __and supports __ media streams
groups payload - qos - combining
PCM - speech - header - information
RTP timestamps - jitter
PSQM - objective - computer
28. 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.
concealment strategy
sequence number and timestamp
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
Handling delay - queuing delay
29. It has a large header of __ bytes - Size of headers IP/RTP/UDP
40 - 20 - 8 - 12
ends - begin - background noise - signal-to-noise threshold
iLBC
sequence number and timestamp
30. The difference between when the packet is expected and when it is actually received is __. - exists only in __ ___ networks
forward error correction (FEC)
PCM - speech - header - information
Jitter - interarrival - packet-based
echo cancelers - software - DSP
31. How does G.729 header go __/__/__
IP - RTP - UDP
queuing - unacceptable
RTP is Realtime Transport Protocol - delay sensitive
payload field - lower
32. Simplify the router - use H.323 gatekeeper or voice managers to avoid __ __
CRTP
jitter buffer
<1%
tandem compression
33. Propagation delay in conjuction with handeling delay can cause noticeable
echo tail - 25
speech degradation
40 - 20 - 8 - 12
last packet - voice
34. 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.
person - computer
software - dynamic - RTP
Serialization delay
payload field - lower
35. To make audio and video work with RTP what do you need. 2 things
begins - front-end speech clipping.
ITU-T - 150
tandom encoding
sequence number and timestamp
36. Time of day of highest calls on circuit focus those on the __
busy house
QoS
IP
jitter buffer
37. ___describes CELP compression that enables __ to be coded into _ Kbps streams;
tandom encoding
forward error correction (FEC)
begins - front-end speech clipping.
G.729 - voice - 8
38. __ __ occurs when you have more than one compression/decompression cycle for each phone call and Voice degradation occurs
queuing - unacceptable
echo cancelers - software - DSP
tandom encoding
Propagation delay
39. __ recommends no more than __ms delay one-way transmission
iLBC
waveform codecs
ITU-T - 150
speech degradation
40. 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)
Latency
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
G.711 PCM
41. __ __ replays the last packet received
Serialization delay
concealment strategy
forward error correction (FEC)
busy house
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 __
PCM - speech - header - information
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
waveform codecs
sizing
43. On a voip link What is the max packet loss
<1%
iLBC
IP
MOS - subjective -1 - 5
44. __ describes __ coding at __ - __ - __ and __ Kbps; you also can interchange ADPCM voice between packet voice and public phone or PBX networks
CRTP
groups payload - qos - combining
G.726 - ADPCM - 40 - 32 - 24 - 16
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
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
continuous media - timing reconstruction
40 - 20 - 8 - 12
person - computer
IP/RTP/UDP - delay - quality - constrained
46. 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
ends - begin - background noise - signal-to-noise threshold
source codecs
sequence information - time-stamping
47. When companies merge make sure you configure the __ __
250 - 250 - 500
dial plan
echo tail - 25
QoS
48. __ is not wasting __ when there is no sound to transmit. At least __ % is wasted
VAD - bandwidth - 50
Latency
payload field - lower
groups payload - qos - combining
49. Using G.729 - just __ conversions from D/A cause the MOS score to decrease rapidly but __ is less resilient
G.729 - voice - 8
2 - G.723.1
jitter buffer
IP
50. Preferred codec for skype - PC to phone apps - A free speech codec suitable for robust voice communication over IP.
RTP timestamps - jitter
VAD - bandwidth - 50
Echo
iLBC