ARP, Address Resolution Protocol, operates at the Data Link layer (Layer 2) of the OSI model. It is responsible for resolving IPv4 addresses to MAC addresses within a local network segment. ARP allows devices on a network to discover each other’s MAC addresses based on their IP addresses, enabling efficient communication between devices at the link layer.
ARP, or Address Resolution Protocol, serves the purpose of mapping IP addresses to MAC addresses within a local area network (LAN). When a device needs to send data to another device on the same network, it uses ARP to determine the MAC address associated with the destination IP address. This mapping is crucial for establishing direct communication between devices using their respective MAC addresses at the data link layer.
The ARP command, commonly used in command-line interfaces (CLI) of operating systems, allows users to view and manipulate the ARP cache on a computer or network device. It provides functionalities such as displaying the contents of the ARP cache, manually adding or removing ARP entries, and clearing the ARP cache to resolve network connectivity issues or update address mappings dynamically.
An ARP table, also known as an ARP cache, is a data structure maintained by network devices to store mappings of IP addresses to MAC addresses discovered through ARP requests and responses. The ARP table helps devices avoid repetitive ARP broadcasts by caching recently resolved address mappings for efficient communication within the local network segment. It is dynamically updated as devices communicate and ARP messages are exchanged, ensuring that devices can quickly locate each other on the network without repetitive address resolution.
An ARP header is a specific part of an ARP message packet that contains essential information for address resolution. It includes fields such as the hardware type (e.g., Ethernet), protocol type (e.g., IPv4), operation code (e.g., request or reply), sender’s hardware address (MAC address), sender’s protocol address (IP address), target’s hardware address (MAC address being resolved), and target’s protocol address (IP address being resolved). The ARP header facilitates the exchange of ARP messages between devices on a network, enabling them to discover and maintain address mappings required for efficient communication at the data link layer.