Proposed Solution

Introduce a new format for scoped addresses:
<scoped_address><delimiter><scope_id>
Example: fe80::1-2
scoped_address = "fe80::1"
delimiter = '-'
scope_id = "2"
Should be applied to both unicast and multicast

Extend library functions that translate between a hostname and a numeric address
takes a literal address in the extended format
returns a numeric address structure that contains the scope ID
Note: we don't recommend you to use any particular library functions