I am reading this article https://www.practicalnetworking.net/series/packet-traveling/host-to-host-through-a-router/ , trying to learn how a packet is delivered between different networks.
**From the perspective of each Router, the Routing Table is the map of all networks in existence. The Routing Table starts empty, and is populated as the Router learns of new routes to each network.
Again, the Routing Table is a map of every network that exists (from the perspective of each router). If a router receives a packet destined to a network it does not have a route for, then as far as that router is concerned, that network must not exist. Therefore, a router will discard a packet if its destination is in a network not in the Routing Table.
What does "the Routing Table is the map of all networks in existence" mean?
Does it mean that every router in public network knows all the other public interconnected networks in the world? (Of course for routers in local/private networks, I think they don't know other public networks, but only know the default gateway (the outermost router).)
Take these 2 images as basic model, if they are correct.
Let's say for example I am in Japan, in network
11.11.11.x and my destination is
126.96.36.199 in Canada, which is in network
222.222.222.x (What I want to say is that there are now having so many more networks between
222.222.222.x). Will the router R1 has a route like:
Method network Interface/Next-Hop
... ... ...
? 222.222.222.x 188.8.131.52
R1 has to know the existence of
222.222.222.x(all the other public networks in the world), or R1 won't be able to deliver the packet even if it knows network
22.22.22.x, according to the article.