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