SUBJECTS
|
BROWSE
|
CAREER CENTER
|
POPULAR
|
JOIN
|
LOGIN
Business Skills
|
Soft Skills
|
Basic Literacy
|
Certifications
About
|
Help
|
Privacy
|
Terms
|
Email
Search
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. Who scored highest in the MOS
forward error correction (FEC)
speech degradation
G.711 PCM
Latency
2. __ builds in some reliability to the connectionless __ protocol - enables reliability with out using the overhead of __ - what protocol send multiples of the same packet __
IP
Handling delay - queuing delay
7 - compressed
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
3. __ the 64 Kbps __ voice coding technique - This is used for the digital voice delivery in the __ or __
40 - 20 - 8 - 12
amplitude - hangover
Serialization delay
G.711 - PCM - PSTN or PBX(voip networks)
4. __ is an _ measurement of voice quality and the __ measures the voice
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
MOS - subjective -1 - 5
PSQM - objective - computer
jitter
5. Is the variation of packet interarrival time.
sequence information - time-stamping
2 - G.723.1
jitter
G.728
6. A __ can trick the human ear into perceiving a higher-quality voice - but a __ cannot be tricked.
RTP is Realtime Transport Protocol - delay sensitive
last packet - voice
person - computer
sequence number and timestamp
7. 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).
G.711 - PCM - PSTN or PBX(voip networks)
person - computer
payload field - lower
source codecs
8. Preferred codec for skype - PC to phone apps - A free speech codec suitable for robust voice communication over IP.
iLBC
DNS - IP
busy house
groups payload - qos - combining
9. RTP uses the __ __ to determine whether the packets are arriving in order - and it uses the __ __ information to determine the interarrival packet time (jitter).
queuing - unacceptable
2 - G.723.1
sequence information - time-stamping
Serialization delay
10. __ Kbps low-delay variation of CELP voice compression 16 kbps
G.728
Propagation delay
G.726 - ADPCM - 40 - 32 - 24 - 16
VAD - bandwidth - 50
11. Is the amount of time it takes to actually place a bit or byte onto an interface. Its influence on delay is relatively minimal.
PSQM - objective - computer
Serialization delay
CRTP
G.726 - ADPCM - 40 - 32 - 24 - 16
12. ___describes CELP compression that enables __ to be coded into _ Kbps streams;
250 - 250 - 500
speech degradation
compression - decompression
G.729 - voice - 8
13. Caused by the length a signal must travel via light in fiber or electrical impulse in copper-based networks.
Propagation delay
<1%
speech degradation
DNS - IP
14. What do you use to compress RTP header to 2 or 4 bytes
iLBC
tandem compression
RTP timestamps - jitter
CRTP
15. This adaptation of jitter buffer __ is effective in compensating for delays.
sizing
G.711 - PCM - PSTN or PBX(voip networks)
ITU-T - 150
sequence number and timestamp
16. 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)
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
groups payload - qos - combining
RTP is Realtime Transport Protocol - delay sensitive
17. ___ ___ are used within Cisco IOS Software to determine what level of ___ - if any - exists within the network.
RTP timestamps - jitter
IP
Propagation delay
MOS - subjective -1 - 5
18. 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)
2 - G.723.1
amplitude - hangover
Jitter - interarrival - packet-based
250 - 250 - 500
19. How does G.729 header go __/__/__
data part - RTP Control Protocol (RTCP).
continuous media - timing reconstruction
IP - RTP - UDP
sequence information - time-stamping
20. Voice samples are packed into the___ ___ of a UDP/RTP packet and thus the network header overhead would be __.
payload field - lower
DNS - IP
7 - compressed
G.728
21. 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.
continuous media - timing reconstruction
groups payload - qos - combining
data part - RTP Control Protocol (RTCP).
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
22. Propagation delay in conjuction with handeling delay can cause noticeable
speech degradation
source codecs
ends - begin - background noise - signal-to-noise threshold
last packet - voice
23. To make audio and video work with RTP what do you need. 2 things
G.728
ITU-T - 150
sequence number and timestamp
RTP timestamps - jitter
24. __ Describes a compression technique that you can use to compress ___or other __ signal components of multimedia service at a low bit rate - MP-MLQ provides greater quality at __ Kbps - CELP provides flexibility at __Kbps
G.723.1 speech or audio - 6.3 - 5.3
sizing
IP
dial plan
25. 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.
PCM - speech - header - information
sequence number and timestamp
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
QoS
26. 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
waveform codecs
ends - begin - background noise - signal-to-noise threshold
2 - G.723.1
27. RTP consists of a __ __ and a control part the called __
continuous media - timing reconstruction
jitter
data part - RTP Control Protocol (RTCP).
groups payload - qos - combining
28. VAD problems in determining when speech __ and __ - and in distinguishing speech from __ __. Its also known as __ __ __ __
sizing
dial plan
concealment strategy
ends - begin - background noise - signal-to-noise threshold
29. Simplify the router - use H.323 gatekeeper or voice managers to avoid __ __
amplitude - hangover
Latency
G.729 - voice - 8
tandem compression
30. PSQM was developed to 'hear' impairments caused by __ and __ and not packet loss or jitter
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
tandem compression
250 - 250 - 500
compression - decompression
31. __ protocol that carries audio and video packets - is the standard for transmitting__ __traffic across packet-based networks
RTP is Realtime Transport Protocol - delay sensitive
Echo
groups payload - qos - combining
amplitude - hangover
32. 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.
DNS - IP
G.729 - voice - 8
software - dynamic - RTP
VAD - bandwidth - 50
33. __ __ occurs when you have more than one compression/decompression cycle for each phone call and Voice degradation occurs
jitter
QoS
tandom encoding
sequence number and timestamp
34. You hear your own voice in the background ( 4wire)
Echo
QoS
Handling delay - queuing delay
7 - compressed
35. __ is not wasting __ when there is no sound to transmit. At least __ % is wasted
RTP is Realtime Transport Protocol - delay sensitive
Echo
VAD - bandwidth - 50
dial plan
36. 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
jitter buffer
dial plan
continuous media - timing reconstruction
37. On a voip link What is the max packet loss
G.711 - PCM - PSTN or PBX(voip networks)
<1%
jitter
last packet - voice
38. __ is a __test given to listeners. The listeners give each sample of speech material a rating of __ (bad) to __ (excellent)
MOS - subjective -1 - 5
payload field - lower
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
G.711 PCM
39. Proxy server is not required in an __ based system
IP
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
tandom encoding
jitter buffer
40. You stop Echo in a PSTN by __ __ and is done in __ which is located on each __
forward error correction (FEC)
RTP timestamps - jitter
Serialization delay
echo cancelers - software - DSP
41. 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
echo tail - 25
sequence information - time-stamping
queuing - unacceptable
42. __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
PCM - speech - header - information
Serialization delay
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
MOS - subjective -1 - 5
43. 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.
<1%
sizing
7 - compressed
Handling delay - queuing delay
44. Time of day of highest calls on circuit focus those on the __
ITU-T - 150
busy house
data part - RTP Control Protocol (RTCP).
forward error correction (FEC)
45. Using G.729 - just __ conversions from D/A cause the MOS score to decrease rapidly but __ is less resilient
RTP is Realtime Transport Protocol - delay sensitive
payload field - lower
2 - G.723.1
last packet - voice
46. 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
echo tail - 25
7 - compressed
sequence information - time-stamping
47. Bob@nextdoorneighbor.com is a __ entry but coverts then to an __ address
DNS - IP
payload field - lower
echo cancelers - software - DSP
<1%
48. If a packet is lost What is replayed? packet loss is common in data networks but not in __
sequence information - time-stamping
amplitude - hangover
ITU-T - 150
last packet - voice
49. The difference between when the packet is expected and when it is actually received is __. - exists only in __ ___ networks
Jitter - interarrival - packet-based
iLBC
begins - front-end speech clipping.
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
50. PCM and ADPCM are examples of __ __
waveform codecs
PCM - speech - header - information
iLBC
begins - front-end speech clipping.