ARP OPERATION

OPERATION

•       The sender knows the IP address of the target.

•       IP asks the ARP to create an ARP request message, with the sender physical address, the sender IP address, and the target IP address.

•       The target physical address is filled with 0’s.

•       The message is passed to the data link layer where it is encapsulated in a frame by using the physical address of the sender as the source address and the physical broadcast address as the destination address.

•       Every host or router receives the frame. All machines excepts the one targeted drops the packet. The target machine recognizes its IP address.

•        The target machine replies with an ARP reply message that contains its physical address. The message is unicast.

•       The sender receives the reply message. It knows the physical address of the target machine.

•       The IP datagram , which carries data for the target machine, is now encapsulated in a frame and is unicast to the destination.