On other medias, such as telephone links, leased lines and Frame Relay, the link is said to be "point-to-point", in that there are only two peers involved in the communication over this link at any time.
Because of this, a point-to-point interface "knows" only of two addresses: itself, and the remote end.
No ARP mechanism is needed on such links, though ARP can be used in a special manner (see below) to "attach" distant hosts to local networks.