ARP provides the essential service of mapping IP addresses to
physical addresses on a network.
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Network Layer End-Station Packet
IP Header Source Address Destination Address Data
172.15.1.1 Logical Address
88 Chapter 1: Building a Simple Network
Figure 1-61 Mapping Layer 2 to Layer 3
The term address resolution refers to the process of binding a network layer IP address of
a remote device to its locally reachable, data link layer MAC address. The address is
???resolved??? when ARP broadcasts the known information (the target destination IP address
and its own IP address). The broadcast is received by all devices on the Ethernet segment.
When the target recognizes itself by reading the contents of the ARP request packet, it
responds with the required MAC address in its ARP reply. The address resolution procedure
is completed when the originator receives the reply packet (containing the required MAC
address) from the target and updates the table containing all of the current bindings. (This
table is usually called the ARP cache or ARP table.
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