1-6Introduction to IPv6 Neighbor Discovery ProtocolThe IPv6 Neighbor Discovery Protocol (NDP) uses five types of ICMPv6 messages to implement thefollowing functions:z Address resolutionz Neighbor unreachability detectionz Duplicate address detectionz Router/prefix discoveryz Address autoconfigurationz RedirectionTable 1-3 lists the types and functions of ICMPv6 messages used by the NDP.Table 1-3 Types and functions of ICMPv6 messagesICMPv6 message FunctionUsed to acquire the link-layer address of aneighborUsed to verify whether the neighbor is reachableNeighbor solicitation (NS) messageUsed to perform a duplicate address detectionUsed to respond to a neighbor solicitationmessageNeighbor advertisement (NA) message When the link layer address changes, the localnode initiates a neighbor advertisementmessage to notify neighbor nodes of the change.Router solicitation (RS) messageAfter started, a host sends a router solicitationmessage to request the router for an addressprefix and other configuration information for thepurpose of autoconfiguration.Used to respond to a router solicitation messageRouter advertisement (RA) message With the RA message suppression disabled, therouter regularly sends a router advertisementmessage containing information such asaddress prefix and flag bits.Redirect messageWhen a certain condition is satisfied, the defaultgateway sends a redirect message to the sourcehost so that the host can reselect a correct nexthop router to forward packets.z H3C S5100-SI/EI Series Ethernet Switches do not support the RS, RA, or Redirect message.z Of the above mentioned IPv6 NDP functions, H3C S5100-SI/EI Series Ethernet Switches supportthe following three functions: address resolution, neighbor unreachability detection, and duplicateaddress detection. The subsequent sections present a detailed description of these three functionsand relevant configuration.The NDP mainly provides the following functions:
