Before a Router routes

Routing is actually what makes our internet what it is, without the router, no packet can travel beyond its local network(switched network). Hence, routing is an indispensable part of the internet.

After all, would it not have been silly to have this huge number of computers around us today and yet they cannot communicate? They can't gist, they can't share resources, they can't ask a friend for something. There is a Yoruba saying that says "one tree cannot make a forest", and truly the forest is what we need to survive, so also, computers need to be able to connect to other computers for them to fully display their rich capability.
 
Imagine this scenario with me;
 
I just moved into Port Harcourt City yesterday for an interview slated for this morning. I'm new and I don't know anywhere.
 
This morning, I woke up in Abuloma area and I am supposed to go to Adaptive IT located in Artillery for my interview.
 
NOTE: For the rest of this theory, know that I and my neighbor are both routers. 
So, currently I have 2 information,
 
1. My current location (Abuloma), that is my source address
2. Where I am going to (Artillery), this is my destination address
 
But i still have other information that I need before I can get to my destination - I need to know the road (path) that will get me to my destination.
 
So what i will do next is to dress up, step out and walk up to my neighbor's door. I give a knock on his door and he steps out to attend to me. We exchange pleasantries, then I ask him, "Sir, please how do I get to Artillery?"
 
He answers me, and says "Friend there are 3 paths (roads) you can take to get to Artillery."
1. You can go through Garrison      - Farther route
2. You can go through Mothercat    - Far route
3. You can go through Slaughter     - Short route
 
So now that my neighbor has provided me this information, what is left for me is to choose the best route which is Slaughter road to get to Artillery on time. (Best always wins).
 
From that simple analogy, let's draw out certain essentials and relate it to the routing world;
 
1. I had a need to move from my current location to another location - this talks about the source address and destination address.
2. I didn't know how to get there so I asked a friend - my friend and I, are both Routers.
3. I had to establish a relationship with my friend(neighbor), so we exchanged pleasantries - this talks about how routers form adjacency with neighbors in order to get routing information.
4. We also exchanged pleasantries so that we can continue to be friends - this talks about how routers must maintain relationship so as to always get updates about routes learnt from those neighbors.
 
Hence, this brings us to where we were actually going: The Router must have the following 5 information before it can route.
 
1. It must know both the source and destination addresses.
2. It must know neighbors from which it can learn routes (remote networks) from
3. It must know all possible routes to the destination
4. It must know the best route to the destination
5. it must know how to maintain and verify routing information
 
Now, the routing process can begin.

I believe this write up has been very helpful.
Thank you.

You can also get more on networking here: http://networkgeeky.blogspot.com/2013/06/before-router-routes.html