RFC 4861 / START HERE
Neighbor Discovery, before the details
IPv6 Neighbor Discovery
Neighbor Discovery helps IPv6 devices find nearby routers and neighbors and learn important details about their local link.
The idea in one picture
A device joins an IPv6 link
Neighbors and routers exchange messages
Local reachability is learned
A simplified picture of the idea; the chapters explain the actual mechanisms.
Why it exists
A newly connected device must discover who is nearby and which router can carry traffic beyond the local network.
A familiar example
A laptop joining an IPv6 network receives a router advertisement and learns a route off the local link.
Helpful background
You can start here without reading another RFC. If these ideas are unfamiliar, these short introductions may help.
What you’ll learn next
Begin with chapter one, or choose a topic.
- Discover routers and on-link prefixesRouter Solicitations can prompt Router Advertisements containing router and prefix information.→
- Resolve a local neighbor addressNeighbor Solicitation and Advertisement map an on-link IPv6 neighbor to a link-layer address.→
- Probe a neighbor that may be unreachableNeighbor Unreachability Detection checks whether the forward path to a neighbor continues to work.→
- Validate a router redirectA redirect can indicate a better first hop, but acceptance is constrained by the existing local routing context.→
- Keep Neighbor Discovery on its trust boundaryLink-local checks limit some remote injection but do not authenticate every local sender.→
This introduction explains RFC 4861 (2007). Read the original RFC ↗