Address Resolution Protocol (ARP):used to match IP address with Mac address.
All layer 3 devices have ARP table (ARP cache) and use ARP.
ARP happens in LAN (Ethernet network)
ARP requests are L2-broadcast, ARP responses are L2-unicast
Here are the process:
Ethernet is a layer 2 protocol
Ethernet frames need a destination address
If the destination mac is in your ARP table, you can send the frame
If it isn’t, you send a broadcast ARP request to find the mac address
If the destination host is in your subnet, you can send the frame directly
If the destination host in in another network, you have to send the frame to your default gateway
You send the frame to the gateway’s mac address
The default gateway is a router
Routers make decision based on layer 3 IP addresses
Routers de-encapsulate the frame to see where they have to send it next…
On an Ethernet network, the router sends the frame to the next mac address…