I’m aware that the mac address is part of the data link layer, but why can’t I just use my MAC address as IP address, too?
Why do I need both addresses?
In: 14
An IP address is like your address and the MAC address is like your fingerprint. You can change your address but you can’t change *who you are*. At least, not under normal circumstances. Someone wants to come talk to you, they need to know both where to find you and who you are.
It isn’t a perfect allegory but it functions for our purposes. The big difference is that computers don’t really care who they are talking to, they just know they need to talk to *some computer* in *some remote network*. The devices closest to the target computer are the ones that worry about the MAC <–> IP mapping.
If you want more details, then the ARP protocol and switch CAM tables is what you need to understand for the actual MAC –> IP map. That table exists on the same network as the remote computer. As far as the other remote computer, all they need is an IP address and a port number (assuming you are doing NAT/PAT) which will uniquely identify a network address.
Latest Answers