Information Technology Reference
In-Depth Information
11.
cRTP and VAD. Both cRTP and VAD reduce the amount of bandwidth used by VoIP
calls. G.729 calls can be reduced from 26.4 kbps to 11.2 with cRTP and to 7.3 with
cRTP and VAD.
12.
A, B, C, and E are fixed; D is variable. Fixed-delay components include processing,
serialization, dejitter, and propagation delays. Variable-delay components include only
queuing delays.
13.
Yo u r e d u c e t h e f r a m e s i z e w i t h f r a g m e n t a t i o n o r i n c r e a s e t h e l i n k b a n d w i d t h . T h e fo r -
mula is serialization delay = frame size/link bandwidth.
14.
PQ-WFQ and LLQ. Both of these queuing techniques use a strict-priority queue. LLQ
also provides class-based differentiated services.
15.
False. The G.114 recommendation specifies a 150-ms one-way maximum delay.
16.
Tr ue. FRF.12 s pec ifie s LFI for Frame Relay net work s.
17.
Ye s . A n R T T o f 2 5 0 m s m e a n s t h a t t h e a v e r a g e o n e - w a y d e l a y i s 1 2 5 m s , w h i c h i s l e s s
than the recommended maximum of 150 ms.
18.
i = D, ii = C, iii = A, iv = B, v = E
19.
i = B, ii = C, iii = A
20.
i = B, ii = D, iii = C, iv = A
21.
C. Q.SIG is the preferred protocol for inter-PBX trunks.
22.
A. cRTP compresses the IP/UDP/RTP headers from 40 bytes to 2 or 4 bytes.
23.
B. The analog signal is filtered and then sampled, and then samples are digitized.
24.
C. The digitizing process is divided into companding, and quantization and coding.
25.
D. All answers are correct.
26.
B. LFI and cRTP should be implemented to help with the serialization delay on
slow-speed WAN circuits. LLQ will not help because the circuit has no congestion.
27.
D. The G.729 codec is recommended on WAN links because of its lower bandwidth
requirements and relatively high MOS.
28.
C and D. cRTP and VAD reduce the amount of IP bandwidth used in IPT calls.
29.
A. CAC prevents new voice calls from affecting existing voice calls.
30.
D. The Cisco Unified CallManager performs the call processing functions of the Cisco
IPT solution.
31.
B and C
32.
A = iv, B = iii, C = ii, D = i.
33.
C
34.
H. RTP is used to transport voice streams between two endpoints.
