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