Neighbor Discovery Table

A Neighbor Discovery Table is a data structure used in computer networking, particularly in IPv6, to store information about neighboring devices on the same network segment. It maps IP addresses to link-layer addresses (e.g., MAC addresses) and tracks the state of neighbor relationships, facilitating efficient packet forwarding and network communication. This table is maintained by the Neighbor Discovery Protocol (NDP) to resolve addresses, detect duplicate addresses, and manage neighbor reachability.

Also known as: ND Table, Neighbor Cache, IPv6 Neighbor Table, Neighbor Discovery Cache, NDP Table

Why learn Neighbor Discovery Table?

Developers should learn about Neighbor Discovery Tables when working with IPv6 networking, network protocol implementation, or system administration, as they are essential for understanding how devices communicate locally without relying on broadcast-based protocols like ARP in IPv4. Use cases include debugging network connectivity issues, optimizing network performance in data centers or IoT environments, and developing network-aware applications that require low-level control over neighbor interactions.

Learning Resources

• docs: RFC 4861: Neighbor Discovery for IP version 6 (IPv6)
• tutorial: IPv6 Neighbor Discovery Table Explained
• docs: Linux IPv6 Neighbor Table Management
• tutorial: IPv6 Neighbor Discovery Protocol - NetworkLessons.com
• video: Understanding Neighbor Discovery in IPv6 - YouTube