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. 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)
DNS - IP
concealment strategy
iLBC
amplitude - hangover
2. __ __ conceals interarrival packet delay variation.
G.723.1 speech or audio - 6.3 - 5.3
purchase leased lines - purchase VPN and use access code - OR put voice on data network
jitter buffer
concealment strategy
3. 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.
G.723.1 speech or audio - 6.3 - 5.3
Handling delay - queuing delay
<1%
echo cancelers - software - DSP
4. __ 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)
PCM - speech - header - information
IP
tandom encoding
5. __ recommends no more than __ms delay one-way transmission
VAD - bandwidth - 50
ITU-T - 150
iLBC
groups payload - qos - combining
6. 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.
continuous media - timing reconstruction
speech degradation
CRTP
7. Is the variation of packet interarrival time.
jitter
Latency
purchase leased lines - purchase VPN and use access code - OR put voice on data network
RTP timestamps - jitter
8. 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
begins - front-end speech clipping.
echo tail - 25
CRTP
busy house
9. How do you fix queuing delay - you would add
software - dynamic - RTP
QoS
Latency
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
10. What do you use to compress RTP header to 2 or 4 bytes
CRTP
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
continuous media - timing reconstruction
busy house
11. 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).
Jitter - interarrival - packet-based
source codecs
busy house
Handling delay - queuing delay
12. __ 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
echo cancelers - software - DSP
tandom encoding
software - dynamic - RTP
13. RTP consists of a __ __ and a control part the called __
IP
Echo
speech degradation
data part - RTP Control Protocol (RTCP).
14. Voice samples are packed into the___ ___ of a UDP/RTP packet and thus the network header overhead would be __.
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
data part - RTP Control Protocol (RTCP).
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
payload field - lower
15. You hear your own voice in the background ( 4wire)
Echo
CRTP
Handling delay - queuing delay
RTP is Realtime Transport Protocol - delay sensitive
16. Preferred codec for skype - PC to phone apps - A free speech codec suitable for robust voice communication over IP.
QoS
G.723.1 speech or audio - 6.3 - 5.3
iLBC
concealment strategy
17. ___describes CELP compression that enables __ to be coded into _ Kbps streams;
Serialization delay
G.729 - voice - 8
7 - compressed
payload field - lower
18. VAD problems in determining when speech __ and __ - and in distinguishing speech from __ __. Its also known as __ __ __ __
ends - begin - background noise - signal-to-noise threshold
PCM - speech - header - information
G.728
Propagation delay
19. 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.
tandem compression
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
groups payload - qos - combining
PSQM - objective - computer
20. Caused by the length a signal must travel via light in fiber or electrical impulse in copper-based networks.
continuous media - timing reconstruction
2 - G.723.1
RTP timestamps - jitter
Propagation delay
21. __ is not wasting __ when there is no sound to transmit. At least __ % is wasted
dial plan
busy house
VAD - bandwidth - 50
sequence information - time-stamping
22. __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
RTP is Realtime Transport Protocol - delay sensitive
last packet - voice
PCM - speech - header - information
Jitter - interarrival - packet-based
23. RTCP provides support for real-time conferencing of __ of any size within an Internet - does not send __ - offers __and supports __ media streams
compression - decompression
G.726 - ADPCM - 40 - 32 - 24 - 16
groups payload - qos - combining
IP/RTP/UDP - delay - quality - constrained
24. ___ ___ are used within Cisco IOS Software to determine what level of ___ - if any - exists within the network.
busy house
RTP timestamps - jitter
G.711 - PCM - PSTN or PBX(voip networks)
jitter
25. Proxy server is not required in an __ based system
QoS
IP
MOS - subjective -1 - 5
echo tail - 25
26. On a voip link What is the max packet loss
Echo
<1%
QoS
7 - compressed
27. __ __ occurs when you have more than one compression/decompression cycle for each phone call and Voice degradation occurs
tandom encoding
MOS - subjective -1 - 5
tandem compression
ITU-T - 150
28. 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
CRTP
amplitude - hangover
forward error correction (FEC)
echo tail - 25
29. Propagation delay in conjuction with handeling delay can cause noticeable
amplitude - hangover
continuous media - timing reconstruction
speech degradation
PCM - speech - header - information
30. __ __ replays the last packet received
QoS
concealment strategy
G.711 - PCM - PSTN or PBX(voip networks)
payload field - lower
31. __ is a __test given to listeners. The listeners give each sample of speech material a rating of __ (bad) to __ (excellent)
CRTP
MOS - subjective -1 - 5
G.728
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
32. The difference between when the packet is expected and when it is actually received is __. - exists only in __ ___ networks
Propagation delay
40 - 20 - 8 - 12
G.726 - ADPCM - 40 - 32 - 24 - 16
Jitter - interarrival - packet-based
33. Using G.729 - just __ conversions from D/A cause the MOS score to decrease rapidly but __ is less resilient
2 - G.723.1
last packet - voice
RTP is Realtime Transport Protocol - delay sensitive
jitter buffer
34. PCM and ADPCM are examples of __ __
40 - 20 - 8 - 12
waveform codecs
IP
amplitude - hangover
35. 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
tandem compression
sequence information - time-stamping
40 - 20 - 8 - 12
36. When companies merge make sure you configure the __ __
data part - RTP Control Protocol (RTCP).
IP
dial plan
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
37. It has a large header of __ bytes - Size of headers IP/RTP/UDP
echo cancelers - software - DSP
40 - 20 - 8 - 12
Serialization delay
Jitter - interarrival - packet-based
38. 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
Propagation delay
DNS - IP
VAD - bandwidth - 50
39. __ is an _ measurement of voice quality and the __ measures the voice
compression - decompression
Latency
jitter
PSQM - objective - computer
40. PSQM was developed to 'hear' impairments caused by __ and __ and not packet loss or jitter
VAD - bandwidth - 50
QoS
compression - decompression
DNS - IP
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)
ends - begin - background noise - signal-to-noise threshold
speech degradation
queuing - unacceptable
PSQM - objective - computer
42. 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
payload field - lower
IP - RTP - UDP
sizing
43. A __ can trick the human ear into perceiving a higher-quality voice - but a __ cannot be tricked.
IP/RTP/UDP - delay - quality - constrained
RTP timestamps - jitter
person - computer
VAD - bandwidth - 50
44. How many times can a digital to analog conversion in my network and PSTN total network happen - __ speech is less robust conversion
2 - G.723.1
purchase leased lines - purchase VPN and use access code - OR put voice on data network
sizing
7 - compressed
45. Bob@nextdoorneighbor.com is a __ entry but coverts then to an __ address
adaptive differential pulse code modulation (ADPCM) - G.726 - 32
DNS - IP
VAD - bandwidth - 50
waveform codecs
46. Simplify the router - use H.323 gatekeeper or voice managers to avoid __ __
tandem compression
G.711 PCM
last packet - voice
jitter buffer
47. If a packet is lost What is replayed? packet loss is common in data networks but not in __
250 - 250 - 500
jitter buffer
last packet - voice
Jitter - interarrival - packet-based
48. Time of day of highest calls on circuit focus those on the __
sequence information - time-stamping
IP - RTP - UDP
busy house
purchase leased lines - purchase VPN and use access code - OR put voice on data network
49. __is characterized as the amount of time it takes for speech to exit the speaker's mouth and reach the listener's ear.
G.729 - voice - 8
Latency
<1%
G.711 - PCM - PSTN or PBX(voip networks)
50. __ builds in some reliability to the connectionless __ protocol - enables reliability with out using the overhead of __ - what protocol send multiples of the same packet __
Reliable User Data Protocol (RUDP) - UDP - TCP - RUDP
data part - RTP Control Protocol (RTCP).
Serialization delay
G.729 - voice - 8