IPv6 link-local address

A link-local address in IPv6 is an address that is automatically assigned to an IPv6 interface. An IPv6 link-local address:

• is assigned within the FE80::/10 range
• is automatically generated on an IPv6 enabled interface
• is unique only on that particular network segment

A link local address can be generated in various ways depending upon the operating system of the device in question. It can be generated either using EUI-64, randomly, or can be manually assigned. A Cisco IOS device by default uses the EUI-64 method to generate the link-local address. A Microsoft Windows device will generate the link-local address randomly by default.

The link-local address is used for neighbor discovery and routing protocol communication.

Links:

https://www.cisco.com/c/en/us/support/docs/ip/ip-version-6-ipv6/113328-ipv6-lla.html#:~:text=A%20link%2Dlocal%20address%20is,a%20EUI%2D64%20format).

https://networklessons.com/ipv6/ipv6-address-types#Link-Local