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