TCP/IP

Question 1

WHAT IS THE ROLE OF TCP/IP

Answer 1

ENABLES different devices to communicate.

Question 2

What are the 4 layers of TCP/IP

Answer 2

1. Application
   2.Transport.
   3.internet/ network
   4 . Link

Question 3

Role of Application

Answer 3

Selects and uses the correct protocol to transmit data.

Question 4

Transport layer?

Answer 4

Establishes an end to end connection between the receiver and the sender.
Splits the transmission into packets.
Each packet has a sequence number which identifies a packets position in relation to their packets that form part of the same message.
Each packet has a port number which identifies which protocol is to be used.
Eg: port 443 HTTPS

Question 5

NETWORK ?

Answer 5

PROVIDES the correct IP address for each packets source and destination.
Also routers work here , use IP addresses on a packet to send it to its destination.

Question 6

LINK ??

Answer 6

Control physical connections between pieces of hardware in a network.
Adds MAC ADDRESSES to packets which it receives from the network layer.
MAC(media access control ) are unique to every device.
MAC addresses identify the hardware to which a packet should be sent and they change after every hop.

Question 7

What happens once a packet has been received by its intended recipient?

Answer 7

ITs stripped off all its extra information and basically reverse TCP/IP

Question 8

Name the steps once a packet is at its receiving end

Answer 8

1. Link layer removes the MAC addresses from the packet.
   2.Network layer removes the IP addresses
2. Transport layer uses the port number to determine the correct application to send the packet to.
3. Transport layer uses the sequence number to ensure that the packets are in the correct order.
4. APPLICATION LAYER receives the packets and displays the information to the user.

Question 9

What is a socket address?
What is its purpose ?

Answer 9

When the IP address is combined with the port number.
So first u write the IP address followed by a colon and then the port number.
Identifies which of the applications on the recipients device a packet should be sent to.

Question 10

What is FTP port no. And explain the purpose for it?

Answer 10

File Transfer Protocal
20 & 21
Sends files between devices and clients can access FTP serves anonymously and non - anonymously

Question 11

SSH port no. ?
Purpose ?

Answer 11

Secure Shell
22
Allows for remote management of computers and it requires a username and password and encrypts the info.

Question 12

SSH clients?

Answer 12

Software that makes a TCP connection to a remote port.
Once a connection is made commands for application level protocols are sent to a remote computer

Question 13

HTTP port no. ?
Purpose?

Answer 13

Hypertext transfer protocal.
80
Basically application software receives text files and gives them a web page, this is because web servers hold web pages.

Question 14

HTTPS port no. ?
Purpose?

Answer 14

Hypertext transfer protocal secure.
443
Performs same function as http but encrypts info during transmission .
This keeps the info sent by the client secure and also prevents from info being tampered with or modified during transmission

Question 15

POP3 port no. ?
Purpose??

Answer 15

Post office protocal 3
110 & 995
Used for retrieving emails form an email server . Communicates with email servers to check and download new messages.

Question 16

SMTP port no. ?
Purpose??

Answer 16

Simple mail transfer protocal
25 , 587 & 465
Used for sending emails.
Used between a client and an email server.

Question 17

Name the two parts that an IP address is split into:

Answer 17

Network identifier
Host identifier.