Ipv6 Neighbor Discovery Protocol; Introduction To Ndp - Zte ZXR10 5900E Series User Manual

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C h a p t e r
IPv6 Neighbor Discovery
Protocol
Table of Contents

Introduction to NDP ...........................................................11

Configuring NDP ................................................................13
IPv6 NDP Configuration Example .........................................14
IPv6 NDP Maintenance and Diagnosis ...................................14
Introduction to NDP
IPv6 does not execute the address resolution protocol (ARP) or
the reserve address resolution protocol (RARP) any more but su-
persedes them with the corresponding functions of the neighbor
discovery protocol (NDP). The following are primary differences
between IPv6 NDP and IPv4 ARP.
� In IPv4, the ARP is an independent protocol. It provides con-
version between IP addresses and link-layer addresses. Dif-
ferent ARPs should be defined for different link-layer protocols.
In IPV6, the NDP contains the ARP functions and runs over the
Internet control message protocol (ICMPv6). It features more
universal, more content, and applicable to various link-layer
protocols.
� ARP protocol, ICMPv4 router discovery and ICMPv4 redirection
packet are based on broadcast, while NDP neighbor discovery
packet is based on the efficient multicast and unicast.
� The reachability detection is meant to determine whether the
host or router represented by the corresponding IP address
can still receive and send packets, to which IPv4 has no unified
solution. The NDP defines the reachability detection process to
ensure that no IP packet will be sent to a black hole.
RFC 2461 (IPv6 neighbor discovery) describes the neighbor dis-
covery mechanism, which provides some different purposes, in-
cluding the following points:
� Router discovery This mechanism helps a host to identify the
local router.
� Prefix discoveryThis mechanism is used by nodes to determine
an address prefix that is used to specify the link-local address
and an address prefix that should be sent to a router for for-
warding.
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