I know this is a very very basic doubt, but never I thought of it in a deep perspective. For example, I am going to use the following scenario:
You know that we usually use a /30 mask when you are configuring a link between two routers, each router with his own interface. My doubt is: ¿why do we need to assing two ip's, for each interface? why it is neccesary a subnet in this link? I say this becasuse, if you have, for example, in router "CE_Valencia" an ethernet wire connected to router "PE_Este", you send the packets to that wire and they are going to arrive to the another router, I dont see the need for such ip's and subnet. I know that I am wrong, but I'd appreciate a good explanation of this, and why this happen. Thanks in advance, hope I have explained enough myself. Thanks in advance.