what is a link-local address?

Link local address allow machines to automatically have an Ip address on a network if they haven't been manually congfigured or automatically configured by a special server on the network(DHCP).Before an address is chosen, the machine sends out a special message using arp to avoid ipaddress conflict.

For IPv4, link-local addresses are assigned from 169.254.0.0/16 (in human-speak that would be 169.254.0.0 ~ 169.254.255.255). For IPv6, it's fe80::/10.

for details.you can refer to rfc 3927.