InARP is an extension of the ARP protocol. We can see an example of this by going to CloudShark at https://www.cloudshark.org/captures/87be3b4b6625 and opening it in Wireshark, as shown here:

InARP is used by the frame relay in the same way as a standard ARP in resolving an IP address. However, InARP does not use broadcasts as it already knows the target hardware address, which is the Data Link Connection Identifier (DLCI) of the desired station. As shown in the following diagram, the sending router, 99.0.0.2, attempts to resolve the IP address of DLCI 3091:

While you may not see an InARP very often, while conducting analysis, you may see a type of ARP called a gratuitous ARP, as outlined next.