Chapter 5- 5.2.1 ARP

ARP table or the ARP cache

*When a packet is sent to the data link layer to be encapsulated into a frame, the node refers to a table in its memory to find the data link layer address that is mapped to the destination IPv4 address. * you can locate an IP address in the table and discover the corresponding MAC address

There are two ways that a device can gather MAC addresses.

1.One way is to monitor the traffic that occurs on the local network segment. 2.Another way a device can get an address pair is to send an ARP request.

Time stamped table

Entries in the ARP table are time stamped in much the same way that MAC table entries are time stamped in switches.

ARP requests

Ethernet broadcast messages

ARP replies.

Ethernet unicast messages

The ARP protocol provides two basic functions:

Resolving IPv4 addresses to MAC addresses Maintaining a table of mappings

The ARP request ???

The ARP request contains the IP address of the destination host and the broadcast MAC address, FFFF.FFFF.FFFF.

Where is the ARP table stored ?

the RAM of the device