week 3

Question 1

what is a computer network ?

Answer 1

two computers that are connected together to share resources.

Question 2

what are protocols in networking?

Answer 2

they are rules that govern how computers exchange data and enable effective communication.

Question 3

what does OSI stand for?

Answer 3

open system interconnect. it shows how data flows from network to another.
- the OSI model breaks down the complex task of computer to computer network communication into 7 layers.

Question 4

what are the different layers of the OSI model ?

Answer 4

• 7 Application layer eg HTTP HTTPS FTP etc..
• 6 Presentation layer eg SSL/TLS (Secure Sockets Layer/Transport Layer Security) for encryption.
• 5 Session layer eg Network Basic Input/Output System, creating session between two machines
• 4 Transport layer eg TCP (Transmission Control Protocol), UDP (User Datagram Protocol)
• 3 Network layer eg router, ipv4 ipv6
• 2 Data link layer eg Switches and Bridges etc
• 1 Physical layer eg Ethernet cables, fiber optics etc

Question 5

what is an ip address ?

Answer 5

It is a number used to uniquely identify a device on a network.
- There are two versions ipv4 & ipv6

Question 6

How many bits are in an ip address?

Answer 6

32

Question 7

how many octects are in an ipv4 address?

Answer 7

4

Question 8

convert 192.168.1.131 to bits
172.16.254.1

Answer 8

11000000.10101000.00000001.100000011

10101100.00010000.11111110.00000001

Question 9

how many classes of ip addresses exist ?

Answer 9

5 classes
A: 1-126
B: 128-191
C: 192-223
D: 224-239
E: 240-255

Question 10

what is subnet mask ?

Answer 10

It is a number that determines how many ip addresses we can have in a network.

Question 11

what is the formular to calculate a subnet ?

Answer 11

2^n-2 where n is the number of borrowed bits