ARP Packet Format:

ARP Packet Field Descriptions

• Ethernet Frame Type---For an ARP request/reply, this field is 0x0806. This is sometimes referred as the Ethertype field. Note that this is not actually part of the ARP packet, but belongs to the Ethernet header.

• Hardware Type---Type of hardware address; this is 1 for Ethernet.

• Protocol Type---Type of protocol address being mapped; this is 0x0800 for IP.

• Hardware Size (hs)---Specifies the length, in bytes, of the hardware address; for Ethernet, this is 6.

• Protocol Size (ps)---Specifies the length, in bytes, of the protocol type address; for IP, this is 4.

• Operation (op)---Specifies the type of operation; ARP request value 1, ARP reply value 2.

• Sender HW address---Hardware address of sender (Ethernet in this example).

• Sender Protocol address---Protocol address of sender (IP in this example).

• Target HW address---Hardware address of target node (Ethernet in this example). If the operation value is 1, this field will be all 0's

• Target Protocol address---Protocol address of target (IP in this example).