Which two techniques can reduce voice packet transfer delay across a link of less than 512 kbps? (Choose two.)
A.
deploy LFI
B.
increase link bandwidth
C.
extend the trust boundary
D.
deploy software compression
E.
increase queue depth
Explanation:
Table. Link-Efficiency Mechanisms
Cisco Press CCDA 640-864 Official Certification Guide Fourth Edition, Chapter 6
I would choose A and D.
Given is a bandwidth of 512Kbps. Increasing this bandwidth is a way but not really a technique to reduce delay. Software compression (cRTP) is recommended by Cisco for links lower than 768Kbps and increases processing time but reduces the serialization delay of the packets. Therefore it reduces delay on slow links.
I would too…A and D
A but not D.
Software compression is not as fast or reliable like hardware compression. So you still have the delay problem. that is why software compression is not a good option to solve the problem.
I would rather choose A and D.
Official Cert Guide p. 556:
Several QoS and bandwidth management mechanisms are used on VoIP networks:
■ cRTP
■ IEEE 802.1Q/P
■ RSVP
■ LFI
■ LLQ
■ Auto QoS