Arp Message Format - H3C S5600 SERIES Operation Manual

ARP Message Format

ARP messages are classified as ARP request messages and ARP reply messages.
illustrates the format of these two types of ARP messages.
As for an ARP request, all the fields except the hardware address of the receiver field are set. The
hardware address of the receiver is what the sender requests for.
As for an ARP reply, all the fields are set.
Figure 1-1 ARP message format
Length of hardware address Length of protocol address Length of hardware address Length of protocol address
Hardware address of the sender Hardware address of the sender
Hardware address of the receiver Hardware address of the receiver
Table 1-1 describes the fields of an ARP packet.
Table 1-1 Description on the fields of an ARP packet
Hardware Type
Protocol type
Length of hardware address
Length of protocol address
Operator
Hardware address of the sender
IP address of the sender
Hardware address of the receiver
IP address of the receiver
Hardware type (16 bits) Hardware type (16 bits) Hardware type (16 bits)
Protocol type (16 bits) Protocol type (16 bits)
Operator (16 bits) Operator (16 bits)
IP address of the sender IP address of the sender
IP address of the receiver IP address of the receiver
Field
Type of the hardware interface. Refer to
1-2 for the information about the field values.
Type of protocol address to be mapped. 0x0800
indicates an IP address.
Hardware address length (in bytes)
Protocol address length (in bytes)
Indicates the type of a data packets, which can
be:
1: ARP request packets
2: ARP reply packets
3: RARP request packets
4: RARP reply packets
Hardware address of the sender
IP address of the sender
For an ARP request packet, this field is null.
For an ARP reply packet, this field carries the
hardware address of the receiver.
IP address of the receiver
1-2
Figure 1-1
Description
Table