PROCESSING AN INCOMING ARP MESSAGE
When an ARP message reaches, the protocol specifies that the receiver must operate two basic steps. First the receiver finds the sender's addresses binding and checks to see if It is represent in the cache. If not, it modifies the cache.
The receiver calculates the operation field of the message to calculate whether the message is a response or a request. If the message is a request, the receiver compares the field TARGET PADDR with the local protocol address. If the two are same, the computer is the target of the request and must transmit an ARP response.