What is the purpose of inverse ARP in Frame Relay networks?

Inverse ARP (Address Resolution Protocol) is used primarily in Frame Relay networks to facilitate the dynamic discovery of IP addresses associated with known Data Link Connection Identifiers (DLCIs). When a router is configured for Frame Relay, it often does not have pre-configured knowledge of the IP addresses that correspond to the DLCIs it uses to communicate with other devices on the network.

By using inverse ARP, a router sends out a request on the frame relay link to find out which IP address is mapped to a specific DLCI. The remote device, recognizing the DLCI as a valid identifier, responds with its IP address, allowing the originating router to build and maintain its routing table dynamically. This process simplifies network configuration and reduces the need for manual setups, enabling devices to communicate without prior knowledge of each other's network addresses.

This functionality is essential for effective communication over Frame Relay networks, where circuits are established dynamically and can change frequently, thereby optimizing the network's adaptability and efficiency.