Extension for link-local address format

IPv6 introduced "link-local address"
unicast: link-local and global
multicast: 15 scope sizes

link-local address must come with link identifier
They are ambiguous if we only have 128bit specified
We need a common notation!

fe80::1234:5432:abcd:ef00%ether0

getaddrinfo/getnameinfo can support it cleanly
getaddrinfo() fills in sin6_addr + sin6_scope_id
getnameinfo() converts sin6_addr + sin6_scope_id into string

fe80::1 --- my machine --- fe80::1