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