Q & A on ARP Results and the TCP/IP Layering Model Q: If ARP is a part of Network layer then after doing the mapping of IP onto the MAC address , which layer does it hand over the result to? Because if returns the results to Network layer then NL will encapsultate that MAC address into the packet and pass it down to the Data Link layer which will take it as data,make the frame and put on the internet, now at the destination computer, how the Data Link layer is going to check for the MAC address to find out whether the frame belongs to the same or different computer becuase the MAC address will be there in the NL packet and not in the Data Link layer frame. A: You've confused the old ISO 7-layer model with the TCP/IP model. In TCP/IP, the encapsulation in a frame and translation from IP-to-MAC address *both* occur at the network interface layer. IP is the layer above (passing down a datagram and a next-hop address, and hardware is the layer beneath (accepting a frame and transmitting it).