Question

(a) Name 3 popular electronic mail access protocols?

(b)

i. What is DNS?

ii. Briefly, describe what it does and how it works?

iii. Why does DNS use a distributed approach as opposed to a single server?

(c) HTTP supports both non-persistent and persistent connections.

i. Describe each type of connection and state which HTTP protocol version supports each type?

ii. How and where is the type of connection specified in the HTTP protocol?

(d) Assume that a new application layer protocol is developed for video conferencing application. Which transport layer protocol do you think will be used and why?

(e) FTP is said to have an "out-of-band" connection. Explain what it means?