Question $3(20$ Marks$)$:

What is the difference between FTP and TFTP protocols?

Question $4(20$ marks$)$

Draw the sender windows for a system using the Go$-$Back$-$N Protocol given the following:

a$.$ Frame $0$ is sent; frame $0$ is acknowledged.

b$.$ Frames $1$ and $2$ are sent; frames $1$ and $2$ are acknowledged.

c$.$ Frames $3,4,$ and $5$ are sent; frame $3$ is acknowledged only.

d$.$ Frames $4,5,6,$ and $7$ are sent; frames $4$ through $7$ are acknowledged.