At layer 2 though, the data is addressed to the next hop. At layer 3, the data is addressed to the host that the data is destined for. A computer can have any number of layer 3 addresses but it will only have 1 layer 2 address per LAN interface. It pertains to the actual hardware interface (NIC) in the computer. The layer 2 address is a physical address. It will pertain to a single protocol (such as IP, IPX, or Appletalk). The layer 3 address is a logical address. The MAC address is a layer 2 (data link) address. The IP address is a layer 3 (network layer) address. I think where a lot of confusion with ARP comes from is in regards to how the IP address and the MAC address work together. It is used to associate a layer 3 (Network layer) address (such as an IP address) with a layer 2 (Data Link layer) address (MAC address). What is ARP?ĪRP stands for Address Resolution Protocol. I've done some revision in order to make the whole thing flow as a stand-alone document and I've also made some revisions to the example.

This article is based off of a series of usenet posts (one in particular) on the -plus news group.

Arp network mac address broadcast