Chapter 3, Problem 6E

a.

Program Plan Intro

Given data:

A user wants to download a 20-page paper of 400KB from their professor. Hence, determine the transmitting time of a 20-page paper of 440KB over the circuits.

$Sizeofthepapers=400KB$

Add an extra 10% to the message and then the size of the papers will become as follows.

$\begin{array}{c}Sizeofthepapers=400+10\%of400\\ =400+40\\ =440KB\end{array}$

b.

Explanation of Solution

Cable modem at 384 Mbps:

Given,

$Cablemodemspeed=384Kbps$

We have,

$1byte=8bits$

Then,

$\begin{array}{c}Cablemodemspeed=\frac{384}{8}\\ =48bytes/\sec ond\end{array}$

The transmitting time can be calculated by using the following formula

c.

Explanation of Solution

Cable modem at 1.5 Mbps:

Given,

$\begin{array}{c}Cablemodemspeed=1.5Mbps\\ =1.5\times 1024\\ =1536Kbps\end{array}$

We have,

$1byte=8bits$

Then,

$\begin{array}{c}Cablemodemspeed=\frac{1536}{8}\\ =192bytes/\sec ond\end{array}$

The transmitting time can be calculated by using the following formula

d.

Explanation of Solution

Cable modem includes V.44 data compression with 6:1 ratio:

Given,

$Datacompressionratio=6:1$

$\begin{array}{c}Cablemodemspeed=1.5Mbps\\ =1.5\times 1024\\ =1536Kbps\end{array}$

Consider a number of bytes in 6:1 ratio with 1536 Kbps speed as follows.

$\begin{array}{c}Cablemodemspeed=1536\times 6\\ =9216bytes/\sec ond\end{array}$

The transmitting time can be calculated by using the following formula