Configuring Arp; Overview; Arp Message Format; Arp Operating Mechanism - HP 1910 User Manual

Configuring ARP

This chapter describes how to configure the Address Resolution Protocol (ARP).

Overview

ARP resolves IP addresses into MAC addresses on Ethernet networks.

ARP message format

ARP messages are classified into ARP requests and ARP replies.
request/reply messages. Numbers in the figure refer to field lengths.
Figure 229 ARP message format
The following describe the fields in
Hardware type—The hardware address type. The value 1 represents Ethernet.
•
Protocol type—The type of the protocol address to be mapped. The hexadecimal value 0x0800
•
represents IP.
Hardware address length and protocol address length—Length, in bytes, of a hardware address
•
and a protocol address, in bytes. For an Ethernet address, the value of the hardware address length
field is 6. For an IPv4 address, the value of the protocol address length field is 4.
OP—Operation code. The type of the ARP message. The value 1 represents an ARP request and 2
•
represents an ARP reply.
• Sender hardware address—Hardware address of the device sending the message.
Sender protocol address—Protocol address of the device sending the message.
•
Target hardware address—Hardware address of the device the message is being sent to.
•
Target protocol address—Protocol address of the device the message is being sent to.
•

ARP operating mechanism

As shown in
follows:
Figure 230, Host A and Host B are on the same subnet. Host A sends a packet to Host B as
Figure 229:
263
Figure 229 shows the format of the ARP