) The ARP table maintains a correlation
between each IP address and its corresponding MAC address.
The bindings in the table are kept current by a process of aging out unused entries after a
period of inactivity. The default time for this aging is usually 300 seconds (5 minutes),
ensuring that the table does not contain information for systems that might be switched off
or that have been moved.
ARP Table
The ARP table, or ARP cache, keeps a record of recent bindings of IP addresses to MAC
addresses. Figure 1-62 shows an example of an ARP table.
I need the
Ethernet
address of
176.16.3.2.
I heard that broadcast.
The message is for me.
Here is my Ethernet
address.
IP: 172.16.3.2 = Ethernet ???
Map IP Ethernet
Local ARP
IP: 172.16.3.2 =
Ethernet: 0800.0020.1111
172.16.3.2 172.16.3.1
Exploring the Packet Delivery Process 89
Figure 1-62 ARP Table
Each IP device on a network segment maintains an ARP table in its memory. This table
maps the IP addresses of other devices on the network with their physical (MAC) addresses.
When a host wants to transmit data to another host on the same network, it searches the
ARP table to see if an entry exists. If an entry does exist, the host uses it, but if not, ARP is
used to get an entry.
Pages:
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150