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Prestige 650M-6x User's Guide
8.2
Introduction to ARP Table
Address Resolution Protocol (ARP) is a protocol for mapping an Internet Protocol address (IP address) to a
physical machine address, also known as a Media Access Control or MAC address, on the local area
network.
An IP (version 4) address is 32 bits long. In an Ethernet LAN, MAC addresses are 48 bits long. The ARP
Table maintains an association between each MAC address and its corresponding IP address.
8.2.1 How ARP Works
When an incoming packet destined for a host device on a local area network arrives at the switch, the
switch's ARP program looks in the ARP Table and, if it finds the address, sends it to the device.
If no entry is found for the IP address, ARP broadcasts the request to all the devices on the LAN. The switch
fills in its own MAC and IP address in the sender address fields, and puts the known IP address of the target
in the target IP address field. In addition, the switch puts all ones in the target MAC field
(FF.FF.FF.FF.FF.FF is the Ethernet broadcast address). The replying device (which is either the IP address of
the device being sought or the router that knows the way) replaces the broadcast address with the target's
MAC address, swaps the sender and target pairs, and unicasts the answer directly back to the requesting
machine. ARP updates the ARP Table for future reference and then sends the packet to the MAC address that
replied.
Syntax:
ip arp status
This command displays the arp port statistics of your Prestige.
ras> ip arp status
received 3 badtype 0 bogus addr 0 reqst in 3 replies 0 reqst out 0
cache hit 865 (99%), cache miss 6 (0%)
IP-addr
192.168.1.200
192.168.1.255
num of arp entries= 2
ras>
8.3
About Ping
Ping is a command you can use to check whether the Prestige can recognize other computers on your local
network. A ping command sends a message to the computer you specify. If the computer receives the
message, it sends messages in reply. Using ping, you can test whether the path to the device is working. To
use it, you must know the IP address or the host name of the computer you are trying to communicate with.
8-2
Type
Time
10 Mb Ethernet 300
10 Mb Ethernet 0
Figure 8-2 ip arp status
Addr
stat iface
00:10:b5:ae:56:9b 41
ff:ff:ff:ff:ff:ff 43
enif0
NULL
IP Configuration
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