Forwarding information base
Okay kiddo, imagine you have a big dictionary (like the one in the library) that has a lot of words and meanings in it. And let's say you have a friend who needs to know the meaning of a certain word.
So, what you do is look up the word in the dictionary and tell your friend what it means. Now, if your friend asks you about another word later on, you have to look it up again and tell them what it means.
Now think of a computer. It also has a "dictionary" (called a forwarding information base) that has information about different places it can send data to. When a device on the network wants to send some data to another device, it asks the computer for help.
The computer then looks up in its "dictionary" to know where it should send the data. It keeps updating its dictionary as it learns more about the network. Now, the next time a device wants to send data to the same place, the computer already knows where it should go and doesn't need to look it up again.
So just like you look up words in the dictionary and remember the meanings, the computer looks up destinations in its forwarding information base and remembers where to send the data!
So, what you do is look up the word in the dictionary and tell your friend what it means. Now, if your friend asks you about another word later on, you have to look it up again and tell them what it means.
Now think of a computer. It also has a "dictionary" (called a forwarding information base) that has information about different places it can send data to. When a device on the network wants to send some data to another device, it asks the computer for help.
The computer then looks up in its "dictionary" to know where it should send the data. It keeps updating its dictionary as it learns more about the network. Now, the next time a device wants to send data to the same place, the computer already knows where it should go and doesn't need to look it up again.
So just like you look up words in the dictionary and remember the meanings, the computer looks up destinations in its forwarding information base and remembers where to send the data!