Networks Horizon

Post office Model- Actual Data Flow -How networks work?


How does post office actually route the packet to its destinations and in many ways computer network works on the same pricipal as post office.

Suppose you have an envelope and you have address it with recipent details and your details in the sender section.Address on envelope is written in hirechical format starting with more specific information(your friends name) followed by the street address and ending with the city and postal code which is most general information. Post office needs each set of information to route the letter correctly to your friend. After writing address, you drop the envolope in post office letter box and then post office van picks up the letter and take it to the nearest post office branch.

Clicking in send button is same like dropping letter in the mail box. Local post office just like an entrance to our network(we can say Router). Then Post office sorts the letter in the specific containers based on the destination using the postal code(This process is like routing table in the router and containers are like next hop address).

Postal code is like destination IP address which is most generic information for the router. As discussed, letters are sorted and put in difference container based on destination postal code (next hop and destination). This process gets repeated until letter reaches the final post office. Notice that envelope might be placed into several difference containers along the way but address on the envelope remains the same.

Another key point is that first post office does't use the entire postal code. It uses just few digits. In the end, sorting process uses entire postal code(destination post office)  This way, envolope makes it way post office to post office towards the final destinatin(last post office).

At the last post office, letters are sorted again based on more specific information like street address. Then post office van dilivers the letter to specific house number on that street. Envolope is delivered to the destination based on most specific information on the envolope i.e name only after it is delivered to the letter box kept at specific house. Person name is examined in the end because more than one person can reside at the same address.

Computer networks work much the same way.