3Com 7757 Configuration Manual page 572

572 C 54: ARP C
HAPTER ONFIGURATION
ARP Table
Table 444 Field descriptions of an ARP packet
Field
Protocol type
Hardware address length
Protocol address length
Operation code
Sender hardware address
Sender IP address
Target hardware address
Target IP address
Table 445 Values of the hardware type field
Value
1
2
3
4
5
6
7
In an Ethernet network, two hosts must know each other's MAC address for them
to communicate with each other. For this reason, each host on the network
maintains an ARP table, which contains some lately used IP address-to-MAC
address mapping entries. Note that this manual only introduces basic
implementation of ARP table. Different manufactures' products may provide more
information about ARP table. On a Switch 7750 Ethernet switch, you can use the
display arp command to display ARP table entries.
Table 446 describes the fields of APR table.
Table 446 Field descriptions of an ARP table
Field
IF index
Physical address
IP address
Description
Type of the protocol address to be mapped. For IP
address, the value of this field is 0x0800.
Length of the hardware address (in bytes)
Length of the protocol address (in bytes)
Type of the packet, which can be:
1: ARP request
■
2: ARP reply
■
3: RARP request
■
4: RARP reply
■
Hardware address of the sender
IP address of the sender
This field is null for an ARP request, and is the hardware
address of the receiver for an ARP reply.
IP address of the receiver
Description
Ethernet
Experimental Ethernet
X.25
Proteon ProNET (Token Ring)
Chaos
IEEE 802.x
ARC network
Description
Index of the physical interface or port on the device owning the
physical address and IP address in the entry
Physical address of the device, a MAC address
IP address of the device