3.$3.$ Answer the below questions:

a)$)$ What are the two key network−$-$layer functions? Explain them briefly

b)$)$ What is Software Defined Networking ($($SDN)?$)?$ Briefly Explain.

c)$)$ Why Intra−$-$AS and Inter−$-$AS routing are different from each other?

d)$)$ What is tunneling? ($($You may explain with an example).$).$

4.$4.$ Answer the below questions:

a)$)$ What is the function of an ARP protocol?

b)$)$ Explain Ethernet CSMA/$/$CD algorithm.

c)$)$ How does $$Slotted ALOHA$$ protocol work?

d)$)$ What mechanism is used in Ethernet protocol to detect frame corruptions?