Basics of networking

The basic unit used in computing to store data is 1 bit [b]. 

In computer networks, on the other hand, the unit of bits per second is used to define the throughput (speed) of the network, expressed in b/s or bps (bits per second).

Of course, 1 bit/s is small, so to use multiples of this unit to determine the size of a file, disk capacity or RAM, regardless of bits rather than bytes, these multiples are:

1.      Kilobit [Kb],

2.      Megabit [Mb],

3.      Gigabit [Gb],

4.      terabit [Tb].

Since in a computer network the unit is in bits, unlike file size or disk capacity, where bytes[B] are used instead of bits[b], the problem of conversion, or unit conversion, arises here.

1 byte[B] equals 8 bits[b] So if we want the size of a file in bytes, we need to multiply the number of bytes by 8. For inverse conversion, i.e. from bits to bytes, we need to do the inverse of multiplication, i.e. division. 

The ability to convert units is best suited to performing calculations on specific examples. Two solutions are described below.

Example 1

Assuming that our bandwidth is fixed at 300 Mbps, let's calculate how much data we download from the internet in two hours.

data:

Time: 2 hours

Bandwidth: 300 Mbps

Calculate:

1. seconds are multiplied by minutes:

120 minutes - 60 seconds = 7200 seconds

2. convert the unit of data transfer from megabits to megabytes per second:

300Mb/s ÷ 8 = 37.5MB/s

3. multiply throughput by time:

37.5 MB/s - 7200 seconds = 270000 MB ~ 270 GB

Answer to example 1: We will download 270 GB in two hours.

Example 2

Let's calculate the time it takes to download a 5 GB file, assuming that the bandwidth of our connection is fixed at 300 Mbps.

data:

File size: 5 GB

Bandwidth: 300 Mbps

Calculate:

1. convert the unit of data transmission from megabits to megabytes per second:

300 Mb/s ÷ 8 = 37.5 MB/s

2. convert file storage units from gigabytes to megabytes:

5 GB => 5120 MB

3. divide the file size by the bandwidth:

5120 MB ÷ 37.5 MB / s = 136.5 seconds ~ 2 minutes 16 seconds

Answer to example 2: We download a 5 GB file over a 300 Mbps connection in approximately 2 minutes 16 seconds.

TASKS TO BE COMPLETED ON YOUR OWN

    Calculate when the contents of a DVD (4.7 GB) can be transferred over a 50 Mbps connection.

    Calculate how much data can be transferred over a 500 Mbps connection in 15 minutes.