The TCP/IP protocol stack

Question 1

What is a TCP/IP ?

Answer 1

a set of networking protocols that work together as 4 connected layers , passing incoming data and outgoing data packets during communication between nodes

Question 2

What are the 4 layers of this protocol stack?`

Answer 2

• application layer
• transport layer
• network layer
• data link

Question 3

What is a protocol stack?

Answer 3

collection of protocol layers used for transmission of data in computer networking, where each layer is responsible for a different aspect of the communication process

Question 4

How can i remember the 4 layers?

Answer 4

a - always
t - transport
n - nerdy
d - data

Question 5

What happens to the packets as they’re transferred between layers?

Answer 5

They’re wrapped and unwrapped

Question 6

What happens at the application layer?

Answer 6

this layer relates to the way of transferring data.
it can be either through FTP, mail, pop3,http(webpage)
it selects appropriate host based on application that sent the data

Question 7

What happens at the transport layer?

Answer 7

it uses the tcp (transmission control protocol) to establish an end to end connection with the recipient device. Here data is split into packets and labelled with a port through which the packet should route, this ensures correct application is to receive
this layer requests re transmission if packets get lost

Question 8

What happens at the internet layer?

Answer 8

adds source and destination address (IP). it forms a socket

Question 9

What is a socket?

Answer 9

the IP address and the PORT. it specifies which device the packet must be sent to and which application is being used

Question 10

What happens at the data link layer?

Answer 10

adds the MAC address of the next device and source to receive the packet (receiver or router if still in transmission) by the correct piece of hardware

Question 11

What happens at the receiving end?

Answer 11

stack acts like a stack (data is popped off)
firstly the mac address is stripped off by data link layer
ip addresses are removed by network layer
transport layer removes port and reassembles packets
data is passed into the right application

Question 12

How often are these layers accessed during transmission?

Answer 12

Initially all layers are accessed
then between routers only the 2 lowest ones are , this is because routers operate on the internet layer, mac addresses are changed