Networking Question (about IP and MAC addresses)

Eternal Paradox

Hello!

So I'm in college, and I somehow landed an awesome internship at this technology company where I live. My new boss likes to teach me by asking questions. He recently asked me a question that I am unable to answer, I was hoping someone here would be able help me out, Rym or Scott or someone with a good amount of knowledge in networking.

Here is the question: We have MAC addresses built into networking devices, why do we have IP addresses, if we already have MAC addresses?

To the best of my knowledge. IP addresses carry more information than a MAC address, but, I'm sure there is more to it.

So can someone help me out?

Omnutia

I suppose we've all got to learn somewhere. Get an earful of this.

Apreche

First of all, there is no guarantee that a MAC address is unique. I can change my MAC address to whatever I want. By default, most equipment comes with a relatively unique MAC address, but there's no guarantee.

The real answer is a matter of routing, and the fact that MAC addresses are on the ethernet layer, which is below the IP layer. If you want everyone to use MAC addresses for everything, then that would basically mean every piece of networking equipment in the world would be plugged into one gigantic ethernet hub. If you know how ethernet works, it's all pretty obvious.

Eternal Paradox

So basically, you need IP addresses to route between networks. Damn, now I feel stupid for not figuring it out on my own.

Thanks for the help and Omnutia for the link to the networking podcast.