How is using of link local address in NDP. We can discover neighbor by using global address. So why we need link local address in NDP?
IPv6 – Using Link Local Address in NDP
ipip-link-localipv6ndpprotocol-theory
ipip-link-localipv6ndpprotocol-theory
How is using of link local address in NDP. We can discover neighbor by using global address. So why we need link local address in NDP?
Best Answer
IPv6 NDP does a lot more than simply what IPv4 ARP did. ND also covers many more things than layer-3 to layer-2 address resolution. See RFC 4861, Neighbor Discovery for IP version 6 (IPv6), Section 3.1. Comparison with IPv4:
Originally, IPv4 did not have link-local addressing, and it was later bolted on to fill a need. When the IETF designed IPv6, it took several things like that and built it into IPv6 from the start. IPv6 requires every IPv6 interface to have a link-local address. That way, all IPv6 hosts are ready to participate, at least, in the local LAN when they are enabled.
There are multiple IPv6 RFCs that explain aspects of IPv6 link-local addressing.
RFC 4291, IP Version 6 Addressing Architecture, Section 2.5.6 Link-Local IPv6 Unicast Addresses:
RFC 4861, Neighbor Discovery for IP version 6 (IPv6):
RFC 4862, IPv6 Stateless Address Autoconfiguration:
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There is also RFC 7404, Using Only Link-Local Addressing inside an IPv6 Network.