Question 1
a) Identify the class of the following IP addresses.
i) 100.168.1.42
ii) 129.0.0.1
iii) 193.33.33.33
iv) 6.7.8.9
v) 225.250.250.1

b) Compare MAC with IPv4 addresses providing an example of each, how those addresses are assigned and what role they play in the operation of a network.

c) Explain how NAT/PAT helped address the IPv4 address shortage problem.

Question 2
a) Routing tables are related to both the routing function and the forwarding function provided by the network layer. Briefly explain how the routing tables relate to the routing function and the forwarding function.

b) Router X and Router Y are initially directly connected in a network system. RIP is the routing protocol running on the routers, and DV (Distance Vector) algorithm is the routing algorithm for RIP. For some reasons the link between Router X and Router Y is broken down.
(i) Will this breakdown trigger Router X to re-compute its DV? Briefly explain your answer.
(ii) Will this breakdown cause the Router X to notify its neighbours of its DV? Briefly explain your answer

c) A network system is described as a graph shown in Figure, with nodes representing routers and edges representing network links.
-image-

Suppose DA = [dA(B), dA(C), dA(D)], DB, = [dB(A), dB(C), dB(D)], DD = [dD(A), dD(B), dD(C)], where DA represents the distance vector for node A, and dA(B) represents the cost of the least-cost path from node A to node B.
At the beginning, the routing table on all the routers are empty.
(i) Give the initialized DA.
(ii) After each router distributed its initialized distance vector,
what is the updated DA? You need to give details of how the updated DA is obtained.