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