Of course, we had to have an automatic mechanism for Layer 3 to Layer 2 mappings. Making just manual configurations could mean a lot of work in a large network. So we can’t use ARP like in Ethernet, but we can use another form of ARP, that is rightly named Inverse ARP. That is because in Frame Relay, when an interface is configured with an IP Address and a virtual circuit becomes active, the router will send an Inverse ARP packet asking who is on the other end of the link. It will also send information about it’s own address. The router on the other end will reply with it’s IP address and will also add the information it received to it’s frame-relay maps.