What is the Address Resolution Protocol (ARP)?

What is Address Resolution Protocol (ARP)?

Address Resolution Protocol (ARP) is a communication protocol used to resolve IP addresses to physical hardware addresses, like a MAC address. It is used to determine the link layer (hardware) address of a host on a local network segment given its IP address.

How does ARP work?

When a computer sends an IP packet to another computer on a local area network (LAN), it needs to know the hardware address of the destination machine. To determine the hardware address, it sends a broadcast packet using the ARP protocol. This broadcast packet asks all machines on the network "who has this IP address?". The machine that owns the IP address responds with its physical hardware address.

Advantages of ARP

• It helps in finding a node's MAC address even when it is on a different subnet.
• It allows for host mobility, as the hosts can move from one subnet to another without having to inform the ARP server.
• It can detect duplicate IP addresses on the same LAN.
• It is a simple protocol that is easy to implement and maintain.