Lesson 3 -B

Question 1

What is computer network?

Answer 1

A computer network consist of two or more computers connected together and sharing data.

Question 2

what is OSI model?

Answer 2

teh OSI model is a standart for communication between computer

Question 3

what is OSI stand for?

Answer 3

Open System Interconnect

Question 4

what are the layers of the OSI Model?

Answer 4

Application (L7), eg: HTTP, HTTPS
6- Presentation , eg
5- Session , eg: creatting session between 2 machines
4 - Transport , eg: TCP , UDP
3- Network , eg: router, ipv4
2- Data link , eg: switches
1- Physical eg: ethernet cables

Question 5

what is the difference between TCP and UDP?

Answer 5

UDP: (User Datagram Protocol) is a “non connection oriented”
protocol ex: video or audio playback
- Data transfer is faster
- UDP doesn’t check if all the packets reach their destination /
it does not resend missing packets.
- Packets are not ordered
TCP: (Transmission Control Protocol) is a “connection oriented”
protocol
- Data transfer takes more time
- Data get transferred completely, and missing packets are resend
- Packets are received in the same order as they are sent
- It has a 3 ways handshake check
* Synchronization: SYN,
* Synchronization Acknowledgement: SYN-ACK,
* Acknowledgement: ACK

Question 6

What is an IP address?

Answer 6

it is a unique number assign to a device on a specific network.

Question 7

Lab: What is the class of the IP address 192.168.1.45?

Answer 7

The first octet is 192. This number is in the range [192, 223]. Therefore the IP address 192.168.1.45 is from class C

Question 8

What is a subnet mask?

Answer 8

it is a number that determine how many ip addresses we can have in the network.

Question 9

what is protocol in Networking?

Answer 9

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

Question 10

convert 192.168.1.131 into bits

Question 11

how many classes of ip addresses exist?

Answer 11

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

Question 12

how many bits are in an ip address?

Answer 12

32

Question 13

how many octets are in an ipv4 address?

Answer 13

4

Question 14

what is the class of the IP address 10.0.0.3 with the subnet 255.255.0.0?

Answer 14

class B

Question 15

What is the Class of the IP address 10.0.0.65 subnet 255.255.255.0?

Answer 15

C

Question 16

what is the formular to calculate a subnet?

Answer 16

2^n-2
where n is the number of borrowed bits
- where - 2 ( Network address + Broadcast (the Gateway address)

Question 17

Let’s convert 192.168.0.1 in bits

Answer 17

192 ⇔ 1 1 0 0 0 0 0 0
168 ⇔ 1 0 1 0 1 0 0 0
0 ⇔ 0 0 0 0 0 0 0 0 and 1 ⇔ 0 0 0 0 0 0 0 1

Question 18

what is the difference betwwen an IP and a MAC Address?

Answer 18

MAC Address: It is the physical address of the NIC card assigned by the manufacturer, it can’t change.
IP Addrress: It is the logical address of the computer, it is assigned by the network administrator
it can change.