ARP (Address Resolution Protocol) operates at layer 2 of the OSI model, specifically the data link layer.
Understanding ARP and its Layer
The Address Resolution Protocol (ARP) is crucial for mapping IP addresses (layer 3 addresses) to MAC addresses (layer 2 addresses) within a local network. Here's a breakdown:
- Layer 2 Focus: ARP's primary function is to determine the hardware or MAC address associated with a given IP address on the same network segment.
- Necessity: Hosts on a network use IP addresses to communicate, but Network Interface Cards (NICs) operate using MAC addresses. ARP bridges this gap.
How ARP Works in Context
ARP facilitates communication by:
- ARP Request: When a host wants to send data to another host on the same network but only knows the IP address, it sends an ARP request. This request broadcasts a message asking, "Who has this IP address? Tell me your MAC address."
- ARP Reply: The host with the matching IP address responds with an ARP reply, containing its MAC address.
- Data Transmission: The originating host now has the necessary MAC address and can send data directly to the destination host.
Table summarizing ARP Layer
| Protocol | Layer | Function |
|---|---|---|
| ARP | 2 | Resolves IP addresses to MAC addresses on local LAN |
