What is a MAC address for?

Question

Computer networks

Why do you need a MAC address if computers on the network at the link layer ping by ip?

Answer 1

because the routing of packets on an Ethernet network is based on the MAC addresses of the end clients.
The IP packet is wrapped in an Ethernet packet wrapper and transmitted to the piece of iron for sending in the form of "impulses" of some distribution medium.
Switch for example is an Ethernet router - it does not even know about IP addresses and in general what is transmitted inside the Ethernet packet wrapper.
The simple Ethernet protocol is now the most used/only OSI link layer protocol for IP networks, and that's why the MAC address is so well known.
Another protocol would spread, its components would be known.

Answer 2

Because network adapters do not know anything about IP, ARP. ping etc. high-level things
MAC - this is the address of the network adapter, it checks on the MAC at the iron level that the packet is intended for it and passes it further up the stack or discards it.

Answer 3

It is at the link layer that computers communicate by MAC address.
The IP address is a layer above - network.
The MAC address is tied to the host hardware (it can be changed, but as a rule it is not changed).
The IP address is assigned by you depending on the network topology (or automatically based on the DHCP protocol).

Answer 4

"Stupid" switches in order to compile a table of addresses (that is, to which interface to send the next packet) uses the MAC address. There are more advanced switches where you can configure different behavior depending on other parameters, including the IP address.
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The simple Ethernet protocol is now the most used/only OSI link layer protocol for IP networks, and that's why the MAC address is so well known.
Another protocol would spread, its components would be known