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