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