Use $c=3^{**}{10}^{{?}^{{?}^{?}}}8\frac{m}{s}$ whenever required.

All questions have equal points.

Question $1$:

You setup a communication channel between two rural cities by letting a vehicle repeatedly carry a package from the sender to the receiver cities. The vehicle travels with an average speed of $20k\frac{m}{h}$ and carries one package at a time. Each package contains $2$ Giga bits of data.

Calculate the data rate of this channel when sending

$($i$)$: $2$ Giga bits of data

$($ii$)$: $6$ Giga bytes of data

$($iii$)$: An infinite stream of data

Question $2$:

A server sends packets to a client via satellite. The packets must traverse one or more satellites before they reach their destination.

The satellites use store$-$and$-$forward packet switching with a switching time of $150$ micro second. If the packets travel a total distance of $30,000km,$ how many satellites do the packets have to pass

$($a$)$: If $1\%$ of the delay is caused by packet switching.

$($b$)$: If $2\%$ of the delay is caused by packet switching.

Question $3$:

Explain why the link layer, network layer, and transport layer each have to add source and destination information to the payload?

Question $4$:

In some networks, the data link layer handles transmission errors by requesting that damaged frames be retransmitted. If the probability of a frame being damaged is $p,$ what is the mean number of transmissions required to send a frame?

Assume that acknowledgements are never lost?