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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. It has a large header of __ bytes - Size of headers IP/RTP/UDP
40 - 20 - 8 - 12
last packet - voice
Echo
IP - RTP - UDP
2. How many times can a digital to analog conversion in my network and PSTN total network happen - __ speech is less robust conversion
7 - compressed
dial plan
jitter
amplitude - hangover
3. Caused by the length a signal must travel via light in fiber or electrical impulse in copper-based networks.
speech degradation
G.711 - PCM - PSTN or PBX(voip networks)
G.723.1 speech or audio - 6.3 - 5.3
Propagation delay
4. Is the amount of time it takes to actually place a bit or byte onto an interface. Its influence on delay is relatively minimal.
Serialization delay
tandom encoding
sizing
amplitude - hangover
5. Time of day of highest calls on circuit focus those on the __
echo cancelers - software - DSP
ends - begin - background noise - signal-to-noise threshold
sizing
busy house
6. The difference between when the packet is expected and when it is actually received is __. - exists only in __ ___ networks
tandom encoding
Jitter - interarrival - packet-based
waveform codecs
PCM - speech - header - information
7. When companies merge make sure you configure the __ __
waveform codecs
dial plan
G.729 - voice - 8
Latency
8. PSQM was developed to 'hear' impairments caused by __ and __ and not packet loss or jitter
sizing
G.711 - PCM - PSTN or PBX(voip networks)
continuous media - timing reconstruction
compression - decompression
9. __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
groups payload - qos - combining
DNS - IP
PCM - speech - header - information
ends - begin - background noise - signal-to-noise threshold
10. Is the variation of packet interarrival time.
busy house
Serialization delay
IP/RTP/UDP - delay - quality - constrained
jitter
11. What do you use to compress RTP header to 2 or 4 bytes
PCM - speech - header - information
<1%
CRTP
7 - compressed
12. This adaptation of jitter buffer __ is effective in compensating for delays.
software - dynamic - RTP
G.711 PCM
jitter buffer
sizing
13. If a packet is lost What is replayed? packet loss is common in data networks but not in __
Handling delay - queuing delay
last packet - voice
compression - decompression
7 - compressed
14. Who scored highest in the MOS
CRTP
last packet - voice
G.711 - PCM - PSTN or PBX(voip networks)
G.711 PCM
15. __ builds in some reliability to the connectionless __ protocol - enables reliability with out using the overhead of __ - what protocol send multiples of the same packet __
2 - G.723.1
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
person - computer
echo tail - 25
16. RTP consists of a __ __ and a control part the called __
data part - RTP Control Protocol (RTCP).
ends - begin - background noise - signal-to-noise threshold
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
purchase leased lines - purchase VPN and use access code - OR put voice on data network
17. You stop Echo in a PSTN by __ __ and is done in __ which is located on each __
7 - compressed
jitter buffer
echo cancelers - software - DSP
RTP is Realtime Transport Protocol - delay sensitive
18. Voice samples are packed into the___ ___ of a UDP/RTP packet and thus the network header overhead would be __.
RTP timestamps - jitter
payload field - lower
7 - compressed
250 - 250 - 500
19. PCM and ADPCM are examples of __ __
software - dynamic - RTP
waveform codecs
MOS - subjective -1 - 5
Propagation delay
20. __ recommends no more than __ms delay one-way transmission
PCM - speech - header - information
echo tail - 25
ITU-T - 150
source codecs
21. Propagation delay in conjuction with handeling delay can cause noticeable
G.711 - PCM - PSTN or PBX(voip networks)
continuous media - timing reconstruction
speech degradation
queuing - unacceptable
22. 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
data part - RTP Control Protocol (RTCP).
Propagation delay
G.711 PCM
forward error correction (FEC)
23. 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
sequence information - time-stamping
person - computer
sizing
24. ___describes CELP compression that enables __ to be coded into _ Kbps streams;
Serialization delay
G.729 - voice - 8
tandom encoding
G.723.1 speech or audio - 6.3 - 5.3
25. How do you fix queuing delay - you would add
QoS
busy house
payload field - lower
concealment strategy
26. ___ ___ are used within Cisco IOS Software to determine what level of ___ - if any - exists within the network.
person - computer
MOS - subjective -1 - 5
RTP timestamps - jitter
Latency
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.
250 - 250 - 500
person - computer
Propagation delay
busy house
28. __ is an _ measurement of voice quality and the __ measures the voice
PSQM - objective - computer
jitter buffer
iLBC
40 - 20 - 8 - 12
29. What are 3 things you can do if they want to implement a corporate dial plan
250 - 250 - 500
VAD - bandwidth - 50
RTP timestamps - jitter
purchase leased lines - purchase VPN and use access code - OR put voice on data network
30. __ describes __ coding at __ - __ - __ and __ Kbps; you also can interchange ADPCM voice between packet voice and public phone or PBX networks
amplitude - hangover
forward error correction (FEC)
Jitter - interarrival - packet-based
G.726 - ADPCM - 40 - 32 - 24 - 16
31. __ 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)
speech degradation
VAD - bandwidth - 50
payload field - lower
32. You hear your own voice in the background ( 4wire)
IP
iLBC
Echo
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
33. __ __ conceals interarrival packet delay variation.
jitter buffer
G.726 - ADPCM - 40 - 32 - 24 - 16
250 - 250 - 500
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
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.
IP
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
continuous media - timing reconstruction
<1%
35. __ protocol that carries audio and video packets - is the standard for transmitting__ __traffic across packet-based networks
concealment strategy
ends - begin - background noise - signal-to-noise threshold
RTP timestamps - jitter
RTP is Realtime Transport Protocol - delay sensitive
36. How does G.729 header go __/__/__
IP - RTP - UDP
waveform codecs
G.726 - ADPCM - 40 - 32 - 24 - 16
QoS
37. RTP uses the __ __ to determine whether the packets are arriving in order - and it uses the __ __ information to determine the interarrival packet time (jitter).
speech degradation
echo tail - 25
sequence information - time-stamping
G.723.1 speech or audio - 6.3 - 5.3
38. 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
sequence number and timestamp
last packet - voice
IP/RTP/UDP - delay - quality - constrained
39. __ is not wasting __ when there is no sound to transmit. At least __ % is wasted
jitter
purchase leased lines - purchase VPN and use access code - OR put voice on data network
RTP timestamps - jitter
VAD - bandwidth - 50
40. 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.
jitter
sizing
G.711 PCM
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
41. On a voip link What is the max packet loss
G.711 - PCM - PSTN or PBX(voip networks)
queuing - unacceptable
<1%
dial plan
42. Proxy server is not required in an __ based system
IP
Latency
RTP is Realtime Transport Protocol - delay sensitive
begins - front-end speech clipping.
43. 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).
source codecs
echo tail - 25
software - dynamic - RTP
person - computer
44. 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
tandom encoding
Serialization delay
IP
45. A __ can trick the human ear into perceiving a higher-quality voice - but a __ cannot be tricked.
IP - RTP - UDP
jitter
person - computer
QoS
46. __ __ replays the last packet received
G.723.1 speech or audio - 6.3 - 5.3
tandom encoding
Serialization delay
concealment strategy
47. 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.
Handling delay - queuing delay
payload field - lower
begins - front-end speech clipping.
jitter buffer
48. __is characterized as the amount of time it takes for speech to exit the speaker's mouth and reach the listener's ear.
person - computer
MOS - subjective -1 - 5
CRTP
Latency
49. __ __ occurs when you have more than one compression/decompression cycle for each phone call and Voice degradation occurs
tandom encoding
40 - 20 - 8 - 12
G.728
forward error correction (FEC)
50. Preferred codec for skype - PC to phone apps - A free speech codec suitable for robust voice communication over IP.
jitter
iLBC
DNS - IP
Propagation delay