just use MAC
Although each device has a unique hardware address, not all are in MAC format. It is theoretically feasible to use only MAC, but the
Compatible with different hardware addresses, it is very difficult to deal with. And the data link layer does not have to deal with the logic of the network layer.
IP only
First of all, you have to figure out that IP belongs to the network layer. Its essence is a virtual Internet network, that is to say, it is a logical address. When it really goes, it is a transfer.
into a hardware address (link layer). Just like a computer, you don't have the hardware, do you want the software to run? It is also theoretically feasible to use only IP,
However, because of the unique identification! But as with the above question, you need to figure out the importance of layering (you will gradually understand). a lot
The logic is placed at the network layer, do you think it is good? !
Summarize
Various networks exist all over the world, and they use different hardware addresses. If these heterogeneous networks can communicate with each other, they must
Do complex hardware address translation work, so it is almost impossible for the user or the user host to complete this work. but IP addressing
solve this complex problem. The virtual interconnection is realized by IP at the network layer, and the hardware address is used at the link layer. For users, this calling process
is transparent.