IPv6

Link local addresses are only locally significant and not routable.
Two or many interfaces on a single Router can have the same Link
local address.

For interconnection between subnets the global prefix must vary that
is a global unicast address must be assigned ( also unique local will
do as long as it is on the local LAN , for public networks global
unicast is a must and nothing else is routable )


Global and unique local can be subnetted (unlike link local fe80::/10)
and will ping on a LAN with separate subnets.

Unique local IPv6 fd00::/48 are not routable on the public network.

Global Unicast 2000::/3