ARP

ARP

1. Helps router decide which data-link address to use when making a new header.

2. Dynamically learns the data-link address (MAC) of an IP host connected to a LAN.

3. Routed Protocol

4. ARP request

   • Defines ARP Reply message
     • Sends a message asking if this is your IP address then reply with your MAC address.
   • Hosts and routers hold the ARP results in the ARP cache.
     • ARP cache times out occasionally.
     • Can be seen using arp-p command on a command prompt.