Does the interface subcommand no arp arpa disable the Address Resolution Protocol (ARP) function for a router interface?

By Advanced Research Projects Agency (ARPA) ARP, you mean “Ethernet interfaces” E, per impostazione predefinita, ARP ARPA is set with no arpsnap. This means that ARPA style ARPs are sent, but both ARPA and Subnetwork Access Protocol (SNAP) are answered. By setting no arp arpa, ARP requests are disabled, although null entries are created for every station to which an ARP request is attempted. You can enable SNAP alone, ARPA alone (the default), both SNAP and ARPA together (send two ARPs every time), or neither SNAP nor ARPA (which is what happens if you set no arp arpawithout setting up any other ARP).