Rules for Ethernet Technology Communication

Well, basically there are two rules -

1. Final communication between two computers connected over ethernet technology will happen using MAC address.
2. Communication between two computers will get switched only if they belong to the same network.

To initiate the communication, a frame will be prepared with following fields -

• Payload (data) - This is the largest field in the frame as it consists of actual data.
• L3 headers - This field contains the source IP address and destination IP address
• L2 headers - This field contains the source MAC address and destination MAC address.

Source IP field -

In the source IP field, source IP will be of the device who is preparing the frame. Sender will refer source IP as its own IP and will put it into the frame.

Destination IP field -

This field consists of the IP address of the device with whom we want to communicate. Normally, it is the user who gives the destination IP address.

Before assigning the destination IP to the frame, device refers to the network card to make sure that is it possible to reach that network or not. If the answer is yes then destination IP is filled. If the answer is no then the frame will be discarded and communication will end there and then itself (just for now). And the reason is above rule number 2.

Source MAC field -

Source MAC address is the MAC address of the device who's IP is in the field of source IP address. And hence the device will refer the ARP table where the source IP will be mapped with the MAC address and that is how the source MAC will be provided.

Destination MAC field -

Destination MAC address is a MAC address of a device who's destination IP is filled in the destination IP field. Device will refer now the ARP table and will witness there is no required destination MAC address. Hence the communication will not happen on the basis of above rule number 1.

Then how end to end communication will happen successfully within the network? We will discuss that in the upcoming article. So! This was the brief explanation about two rules for ethernet technology communication. See you in the next article!