TCP/IP

Question 1

Protocol

Answer 1

Set of rules that specify how computes can communicate with each other.

Question 2

Encapsulation

Answer 2

In the TCP/IP stack, when data is received, its ‘wrapped’ in the information the layer has to offer, then passed to the layer below. Like putting the information in an envelope, writing something on the outside then passing it to the layer below.

Question 3

Application layer

Answer 3

Wraps the data with the correct protocol based on the application. Then passes it to the layer below.

Question 4

Transport layer

Answer 4

Receives the data from the application layer, then segments it into packets.
If data is needed to be complete, like a webpage or email, then it wraps it in the TCP protocol, which keeps track of each packet to ensure it isn’t lost by numbering each segment, then the receiver can tell them which numbers didn’t arrive, so they can be resent. If not all data is absolutely needed and speed can be prioritised, then UDP is used, like in streaming etc. A port number is also wrapped on, before this is then passed down to the layer below.

Question 5

Internet layer

Answer 5

Receives data, and encapsulates it all in the IP, and also adds the headers of the IP destination, the source and the number of packets

Question 6

Link layer

Answer 6

Encapsulates the data into a ethernet frame. Also adds the MAC address for the destination router, which is hardwired into the NIC (network interface card). Passes it to the link layer of the destination.

Question 7

Reception of the data.

Answer 7

The packets first arrive in the link layer, and work there way up, decapsulating the relevant information on each layer.