Reason for using multiple routers than single router in Internet Architecture

In the previous blog (https://samhith1053.medium.com/switches-and-routers-in-networking-f3864327b947)

We have discussed how personal computers communicate with switches and routers . In this blog we discuss how the Internet works.

Consider the below figure.

Internet Architecture

This is the simplified version of Internet architecture. Actually there will be a lot of routers and switches in between the source computer and destination computer. The Internet means connecting all the LAN’s around the world.

Question 1: why routers are so important on the internet?

We studied in the previous blog routers are the networking devices which connect different LAN’s. And we know that internet is connecting LAN’s so we have many routers in the internet.

Question 2:would come up in the mind is why there are many routers instead of single router?

So let’s consider that only one router is present which connects all the LAN’s on the world. There could be many routing entries in the router.

There could be several millions of requests from some or other devices. RAM in the router would get consumed up and Router shuts down in very little time.This could result in Single Point Failure Problem. Means if the router shuts down then the whole internet would collapse.

Second problem is the cable length problem. The cable length should be very high for the LAN’s which are geographically farther from the single router.

So we cannot design the internet architecture using one router.